The Classic Surtarbrandur Floras more

Chapter 5 The Classic Surtarbrandur Floras Abstract The classic Surtarbrandur floras of Iceland are 12 Ma (late Serravallian) and belong to the Brjánslækur-Seljá Formation. They make up the most diverse macroflora known from the Miocene of Iceland, with the highest number of exotic angiosperms recorded from this period (Laurophyllum, Liriodendron, Magnolia, Platanus, and Sassafras). Unlike in the older and younger floras, Fagus is absent from the macrofossil and pollen record, suggesting that the older F. friedrichii had not yet been replaced by the later immigrating F. gussonii. The plant assemblages recovered from the Brjánslækur-Seljá Formation represent azonal riparian lowland and upland forests and zonal hardwood forests in the vicinity of a lake followed higher up by mixed broad-leaved deciduous and conifer forests. The plant assemblages reflect the culmination of warm and moist vegetation in Iceland in the late Serravallian. The climatic and vegetation optimum recorded in Iceland for this stage does not reflect the general trend of cooling after the Mid-Miocene Climatic Optimum (17–15 Ma), as seen in many other floras in the northern hemisphere. 5.1 Introduction Plant fossils from Surtarbrandsgil had already been mentioned in the seventeenth century in Museum Wormianum (Worm 1655), although their true nature had not been recognized at that time. The first scientific collection and description of fossil plants from this locality date back to the eighteenth century when Eggert Ólafsson and Bjarni Pálsson explored Iceland on behalf of the Danish Royal Academy of Sciences (see Chap. 2). Fossils from the Brjánslækur-Seljá Formation were later described by Heer (1868), Windisch (1886a, b), Friedrich (1966), and Akhmetiev et al. (1978). Friedrich and Símonarson (1981) claimed that the Surtarbrandsgil gully at the Brjánslækur farm is the longest known and “most interesting” among all the plant localities in Iceland, and Mai collectively termed all Miocene plant localities from Iceland “Florenkomplex Brjánslaekur” (Mai 1995, p. 343). The same author pointed out that no equivalent forest type is known from the remaining Brito-Arctic Igneous Province, Western Europe or North America. T. Denk et al., Late Cainozoic Floras of Iceland, Topics in Geobiology 35, DOI 10.1007/978-94-007-0372-8_5, © Springer Science+Business Media B.V. 2011 233 234 5 The Classic Surtarbrandur Floras (12 Ma) The Brjánslækur-Seljá Formation can be traced along the coastline of the southwestern part of the Northwest Peninsula. The formation is named after two outcrops where macrofossils are found in vast numbers, at the river Seljá in the Vaðalsdalur valley and the Surtarbrandsgil gully near the farm Brjánslækur (Fig. 5.1, Plate 5.1). Friedrich (1966) and Akhmetiev et al. (1978) emphasised the floristic affinities of the 12 Ma floras of Iceland with modern vegetation types of eastern North America and speculated that Iceland was initially colonized from North America. In addition, Friedrich (1966) and Mai (1995) pointed out the pioneer character of the flora from Surtarbrandsgil and other Miocene floras from Iceland as reflected in the presence of taxa such as Comptonia, Acer, Populus, Salix, Sassafras, and Betulaceae. The present chapter describes the floras, vegetation types, and changing environments during the late Serravallian, using regional geology and macro- and microfossils (Table 5.1; Plates 5.1–5.27) from the 12 Ma sediments of Seljá in Vaðalsdalur and Surtarbrandsgil near Brjánslækur (Fig. 5.1). Differences in the composition and abundance of fossil taxa and in sediment type and structure between the outcrops and their bearing on diverse environments during the time of accumulation are evaluated. In addition, environmental changes in Iceland during the Middle Miocene are compared to changes observed in Arctic North America and Europe. 5.2 Geological Setting and Taphonomy The age determination of the Brjánslækur-Seljá Formation is based on absolute age determination from McDougall et al. (1984) and palaeomagnetic measurements (Friedrich 1966; Grímsson 2007) correlated to the world Cainozoic magnetotimescale by Berggren et al. (1995). Sediments of the 12 Ma formation are found along the southern coastline of the Northwest Peninsula. The sediments and fossil floras described in this chapter are located on a small cape, delineated by the Barðaströnd coastline on its western side and Vatnsfjörður fjord on its eastern side (Fig. 5.1). On this cape, sediments can be traced up the Vaðalsdalur valley on the western side of Mount Blankur, Mount Hamarshyrna, Mount Kikafell, and Mount Þverfell, and in the Brjánslækur area on the eastern side of this mountain ridge. Although thick sediments are traceable for several kilometres, macrofossils have only been found at few outcrops. The most prominent are the Seljá outcrop (Plate 5.1), situated high up in the Vaðalsdalur valley, and the Surtarbrandsgil outcrop (Plate 5.1), northwest of the farm Brjánslækur (Fig. 5.1). The clastic sedimentary rock succession in the Vaðalsdalur region is between 10 and 18 m thick. Most outcrops have varying sandstones (fine- to coarse-grained) or siltstones. At Seljá (Fig. 5.2), the lowest part of the succession is made up of conglomerates and coarse sandstones. The sandstone unit is just over a metre thick and is followed by finely laminated (<1 mm to 1 cm thick layers) siltstone, ca 5 m thick. The siltstones are dark coloured and rich in organic detritus. They are followed by a ca 3 m thick sandstone unit. The sandstones are fine- to coarse-grained, dark greyish in colour, and form 1–5 cm thick layers. Coarser sandstones and conglomerates Fig. 5.1 Map showing fossiliferous localities of the 12 Ma formation. (a) bedrock geology (see Fig. 1.10 for explanation), (b) extension of sedimentary rock formation, (c) Surtarbrandsgil and Seljá localities (geological background modified after Jóhannesson and Sæmundsson 1989; altitudinal lines from Landmælingar Íslands 1984). Scale bar in kilometres 236 5 The Classic Surtarbrandur Floras (12 Ma) Table 5.1 Taxa recorded for the 12 Ma floras of Iceland Brjánslækur-Seljá Formation Taxa Pollen Bryophyta Hepaticae gen. et spec. indet. + Lycopodiaceae Lycopodium sp. + Equisetaceae Equisetum sp. Osmundaceae Osmunda parschlugiana Polypodiaceae Polypodiaceae gen. et spec. indet. 1 + Polypodiaceae gen. et spec. indet. 2 + Incertae sedis - unassigned spores Trilete spore fam. gen. et spec. indet. 1 + Ephedraceae Ephedra sp. + Cupressaceae incl. Taxodiaceae Cryptomeria anglica Cupressaceae gen. et spec. indet. 2 + (Glyptostrobus sp.) Cupressaceae gen. et spec. indet. 4 (Sequoia sp.) + Pinaceae Abies steenstrupiana + Cathaya sp. + Picea sect. Picea + Pinus sp. 1 (Diploxylon type) + Tsuga sp. + Sciadopityaceae Sciadopitys sp. + Aquifoliaceae Ilex sp. 1 + Betulaceae Alnus cecropiifolia (+) Alnus gaudinii (+) Betula islandica + Carpinus sp. MT1 (+) Carpinus sp. MT2 (+) Corylus sp. Calycanthaceae aff. Calycanthaceae + Caprifoliaceae Lonicera sp. 1 + Viburnum sp. + Cyperaceae Cyperaceae gen. et spec. indet. A Leaves RP Cuticle DM 1a 1a + + 1a 1a 1a 1a 1a 1b + + 2a 2a 2a + + + + +D + +D + 2a 2a 2a 2a 2a 1b + + + + + + + + (+) D (+) D + +D (+) D (+) D 1a, 2a 1a, 2a 1a 2a 2a 2b, 3 1b 1b 1b 1b (continued) + 5.2 Geological Setting and Taphonomy Table 5.1 (continued) Brjánslækur-Seljá Formation Taxa Ericaceae Rhododendron sp. 1 ? Rhododendron sp. 2 Juglandaceae Carya sp. cf. Juglans Pterocarya sp. Lauraceae Laurophyllum sp. (Laurus) Sassafras ferrettianum Lemnaceae Lemna sp. Magnoliaceae Liriodendron procaccinii Magnolia sp. Myricaceae Comptonia hesperia Oleaceae cf. Fraxinus sp. Platanaceae Platanus sp. Poaceae Phragmites sp. Rosaceae Rosaceae gen et. spec. indet. A Rosaceae gen et. spec. indet. B Rosaceae gen et. spec. indet. C Sanguisorba sp. Salicaceae Populus sp. A (ex group P. tremula L.) Salix gruberi Sapindaceae Acer askelssonii Acer crenatifolium subsp. islandicum Smilacaceae Smilax sp. Trochodendraceae Tetracentron atlanticum Ulmaceae aff. Cedrelospermum sp. Ulmus cf. pyramidalis Valerianaceae Valerianaceae gen. et spec. indet. 237 Pollen + + + + Leaves RP Cuticle DM 1a, ?2a 1a, ?2a 3, 2b 3, 2b 2a 1b 1b 1b + + + + + + + + +D + + (+) (+) (+) + + + + (+) D (+) D (+) D +D +D 1b, 2b 1b 1b 2a 2a 1b 1b 1b 1b 1a 1a 1a 2a 2a 1b 2a 2a 2a 1a (continued) + (+)2 (+)2 + + + + + +D +D +D + + + + 238 5 The Classic Surtarbrandur Floras (12 Ma) Table 5.1 (continued) Brjánslækur-Seljá Formation Taxa Pollen Leaves RP Cuticle DM Incertae sedis - Magnoliophyta + ? Dicotylophyllum sp. A Pollen type 1 + ? Pollen type 2 + ? Pollen type 3 + ? Pollen type 4 + ? Pollen type 5 + ? Pollen type 6 + ? Pollen type 7 + ? L leafy axis, A fruit attached to leafy axis, D fruit dispersed, RP reproductive structure, + organ present, + original description of species based on this organ, (+) organ belonging to genus but uncertain to which of the species, (+)2 indicating number of pollen types possibly belonging to the eponymous morphotaxon, DM dispersal mode: 1a wind long distance (anemochory), 1b bird long distance (endozoochory), 2a wind short distance (anemochory), 2b animals short distance (exozoochory), 3 dyschory alternate with more fine-grained sandstones. A second siltstone unit overlies the sandstones but it is distinct from the lower one. The change from sandstone to siltstone is marked by intermixing units of sand- and siltstones. The siltstones are light coloured, brownish to yellowish, and poor in plant debris. Diatomite lenses become prominent in the upper part of the section. At the top of this section, diatoms become the main sediment type and a 20 cm thick diatomite bed contains the best preserved macrofossils (Fig. 5.2). Above the diatomite, a second compact sandstone unit follows. These sandstones are yellowish in colour and assorted with rhyolitic tephra (coarse tuffaceous sandstones). The lower part of this sandstone unit is cross-laminated. The sandstones are followed by a siltstone unit similar to the middle one. A distinct contact zone between the clastic sediments and the overlying volcanic mixture of pyroclastic, pillow and cube-jointed lava is visible (Fig. 5.2). There are also numerous ash and tephra layers in this section, mostly light-greenish in colour, but clearly with a high content of pumice fragments. The colour and structure are a result of alteration during the conversion of loose tephra to sedimentary rock. Sediments in the Brjánslækur region are 8–20 m thick. The most interesting succession – in terms of plant macrofossils – is exposed in the Surtarbrandsgil gully (Plate 5.1). The sediments in this area differ slightly from those in Vaðalsdalur. Sandstones in the lowest part are followed by prominent homogeneous siltstones. The repeated sandstone units seen in Vaðalsdalur are not as distinct at this site. The lowest part of the succession in Surtarbrandsgil corresponds to the thin conglomerate bed and sandstones in Seljá (Fig. 5.2). Following the ca 3 m thick sandstone bed is an almost continuous siltstone unit towards the top. These siltstones are brownish in colour and correspond to the upper two siltstone units at Seljá. In Surtarbrandsgil, the siltstones contain thin layers of sandstones. These are both of clastic or erosional origin and reworked tephra layers (tuffs). In addition, several lignite lenses and layers occur within the siltstones. In the upper part of the Surtarbrandsgil succession, a diatomite bed similar to the one identified at Seljá is present. As at Seljá, a distinct contact Fig. 5.2 Generalized geological sections from Vaðalsdalur valley and the Brjánslækur region. Geological sections illustrate the sediments at Seljá and Surtarbrandsgil outcrops. C = correlation. C1 lowest conglomerate, C2 first sandstone unit, C3 diatomite, C4 triple ash layer, C5 hyaloclastite 240 5 The Classic Surtarbrandur Floras (12 Ma) Fig 5.2 (continued) between the clastic sediments and overlying volcanic mixture of pyroclastics, pillow, and cube-jointed lava is seen in the Surtarbrandsgil succession (Fig. 5.2). Fossils are found in a lens up to 3 m thick and 25 m wide. In this lens, finely laminated siltstones with interlaminated diatomite are prominent (Fig. 5.2). The fine-grained sedimentary rocks split along the lamination and well-preserved plant fossils are found. Fossils from Seljá are preserved as true impressions (Chaloner 1999) with no organic material present. Most of the fossils are reddish-brown leaf imprints in the fine-grained yellowish diatomite (Plate 5.1). In few instances, more robust organs such as catkins and fruits are preserved as lignified compressions. Plant fossils from Surtarbrandsgil show different preservation and are mostly cleavage impressioncompressions (Chaloner 1999). When the fine-grained sediments at Surtarbrandsgil are split, a black lignite compression is present on the lower part and a white diatomite counterpart replica is on the upper part (Plate 5.1). 5.3 Floras and Vegetation Types The Brjánslækur-Seljá Formation comprises a total of 65 taxa (Plates 5.1–5.27). Most taxa recorded (33) belong to woody angiosperms. Gymnosperms (mainly conifers and Ephedra) and ferns are represented by ten and eight taxa, respectively, while herbaceous angiosperms play a minor role (four taxa; Fig. 5.3). Macrofossils and pollen contribute more or less equally to the observed plant diversity (42 taxa represented by pollen, 35 by macrofossils). Twenty-eight taxa are documented by pollen only, and 15 by macrofossils only; 18 taxa are known from pollen and macrofossils. The macroflora of the Brjánslækur-Seljá Formation is the most diverse of all Cainozoic sediments of Iceland. At Seljá, the fossil assemblage is dominated by foliage belonging to Salix gruberi, Alnus cecropiifolia, and Populus sp. (ex group P. tremula). Over 90% of the broadleaved-type leaf fossils belong to one of these three types. Salix is the most common, followed by Alnus and Populus. Phragmites sp. and Equisetum sp. leaves and axes, and especially rhizomes, are frequently found and are characteristic for the lowest part of the diatomite bed. Other plant fossils identified as Alnus cf. kefersteinii, Betula islandica, Carpinus sp. 3 (bract), Pterocarya sp., Magnolia sp. 2, Rosaceae gen. et spec. 5.3 Floras and Vegetation Types 241 Fig. 5.3 Distribution of life forms and higher taxa among the plants recovered from the 12 Ma sedimentary rock formation. Height of columns indicates number of taxa indet. types A and D, Populus sp., and Acer crenatifolium subsp. islandicum are rare and only few specimens have been found. It is noteworthy that many taxa represented at Seljá by diaspores are known from leaves only or absent in Surtarbrandsgil (cones and catkins of Alnus, bracts of Carpinus, seeds of Magnolia, and catkins of Populus). This points to a species-poor oxbow lake situation at Seljá, with Phragmites in the littoral zone, and Equisetum in the undergrowth of a riparian Salix, Alnus, Populus stand. Rare remains of diaspores were blown in by wind or transported by water. Most of the fossils from Surtarbrandsgil are leaves, but cones and cone scales are also found. Leaves of Alnus cecropiifolia, Betula islandica, and Acer crenatifolium subsp. islandicum are by far the most common types (Table 5.1). Other common elements belong to Alnus gaudinii, Magnolia sp. 1, Sassafras ferrettianum, and Rosaceae (type A). Among the more rare elements are Laurophyllum sp., Comptonia hesperia, and Smilax sp. Leaves of Phragmites are rarely found at this locality. Among gymnosperms, leafy axes of Cryptomeria anglica are most abundant, followed by various organ fossils of Picea section Picea. Ferns and fern allies are rarely found at Surtarbrandsgil, and only a few examples of Equisetum sp., and single specimens of Osmunda parschlugiana and Dryopteris sp. have been recorded. One layer is rich in leaf remains of conifer needles (Cathaya). Many of the macrofossils found at Surtarbrandsgil and Seljá probably came from plants growing close to the sites of accumulation. The high amount of complete leaves in the Surtarbrandsgil sediments indicates short transport for many of the leaf types, suggesting that the place of origin was close to the accumulation site (autochthonous to semiautochthonous). Several of the more common plant fossils 242 5 The Classic Surtarbrandur Floras (12 Ma) from Surtarbrandsgil and Seljá, such as Alnus, Betula, Salix, Populus, and Acer, are today typical components of deciduous riparian forests along streams and rivers and at lake margins. The presence of Phragmites is also indicative of riparian vegetation. In contrast, compressions of branchlets of Cryptomeria are very abundant in the sediments from Surturbrandsgil, but occur in more coarse-grained, sandy layers that are devoid of angiosperm leaves. This suggests transport of Cryptomeria remains from upland forests. Features such as buried stratovolcanoes and lava-filled valleys suggest that the palaeo-topography in Iceland was very similar to modern conditions. Today, the elevation of mountains in Iceland is limited to a maximum of ca 2,500 m a. s. l. by the strength of the oceanic crust beneath the island. This would imply that a complex landscape with a pronounced relief up to 2,000 m (stratovolcanoes) existed in the Miocene (Fig. 5.4). Iceland probably had vast lowlands that changed into highlands where volcanic mountains stood high up from their surroundings, and rivers and streams eroded canyons and valleys. Given the fact that sediments reflect different environments and that there was some altitudinal range in the region, the vegetation can be divided into wetland vegetation (aquatic vegetation, backswamp forests in Table 5.2); levée forests, well-drained lowland forests including lakeshore woodlands; Fig. 5.4 Schematic block diagram showing palaeo-landscape and vegetation types for the late Middle Miocene of Iceland. See Table 5.2 for species composition of vegetation types Table 5.2 Vegetation types and their components during the late Middle Miocene of Iceland Vegetation types 12 Ma Aquatic vegetation Lemna sp. 5.3 Floras and Vegetation Types Backswamp forests and temporally flooded lake margin Lonicera sp. 1 Platanus sp. Pterocarya sp. Sassafras ferrettianum Smilax sp. Osmunda parschlugiana Equisetum sp. Glyptostrobus sp. Alnus cecropiifolia Alnus gaudinii aff. Calycanthaceae Ilex sp. Phragmites sp. Populus (ex group P. tremula) Pterocarya sp. Salix gruberi Smilax sp. Valerianaceae gen. et spec. indet. Viburnum sp. Foothill forests Lycopodium sp. Polypodiaceae gen. et spec. indet. 1, 2 Abies steenstrupiana Cathaya sp. Picea sect. Picea Sequoia sp. Tsuga sp. Acer askelssonii Acer crenatifolium subsp. islandicum Ravine forests aff. Calycanthaceae Corylus sp. Alnus cecropiifolia Alnus gaudinii Betula islandica Carpinus sp. 1, 2 Carya sp. aff. Cedrelospermum sp. zonAL VeGeTATIon Rocky outcrop forests Lycopodium sp. Ephedra sp. Abies steenstrupiana Cathaya sp. Comptonia hesperia Picea sect. Picea Pinus sp. 1 Sanguisorba sp. Tetracentron atlanticum Tsuga sp. Corylus sp. Ilex sp. Laurophyllum sp. (Laurus) Liriodendron procaccinii Lonicera sp. 1 Rosaceae gen. et spec. indet. A Rosaceae gen. et spec. indet. B Rosaceae gen. et spec. indet. C Tetracentron atlanticum Ulmus cf. pyramidalis Levée forests and well-drained lake margins Hepaticae gen. et spec. indet. Lycopodium sp. Polypodiaceae gen. et spec. indet. 1, 2 Rhododendron sp. 1 Acer crenatifolium subsp. islandicum Carya sp. Viburnum sp. Rhododendron sp. 2 cf. Juglans Liriodendron procaccinii Fraxinus sp. Well-drained lowland forests and lake margins Hepaticae gen. et spec. indet. Osmunda parschlugiana Acer askelssonii Acer crenatifolium subsp. islandicum Betula islandica aff. Calycanthaceae Carpinus sp. 1, sp. 2 Carya sp. aff. Cedrelospermum sp. Ilex sp. Liriodendron procaccinii Lonicera sp. 1 Magnolia sp. Platanus sp. Pterocarya sp. Rosaceae gen. et spec. indet. A Rosaceae gen. et spec. indet. B Rosaceae gen. et spec. indet. C Tetracentron atlanticum Valerianaceae gen. et spec. indet. Sassafras ferrettianum Smilax sp. Ulmus cf. pyramidalis Viburnum sp. Montane forests Lycopodium sp. Dryopteris sp. Polypodiaceae gen. et spec. indet. 1, 2 Abies steenstrupiana Cathaya sp. Cryptomeria anglica Picea sect. Picea Sciadopitys sp. Tsuga sp. Fraxinus sp. Viburnum sp. AzonAL VeGeTATIon 243 The palaeoecology of fossil species is reconstructed from their sedimentological context and ecology of modern analogues 244 5 The Classic Surtarbrandur Floras (12 Ma) and upland forests (foothill forests and montane forests in Table 5.2). In addition, some plants are indicative of rocky outcrop vegetation and ravine situations. 5.3.1 Wetland Vegetation Plant remains associated with wetland vegetation (aquatic and swamp vegetation) belong to taxa that either float (Lemna) or grow in habitats with fluctuating ground water tables (Table 5.2). A number of taxa are typical elements of the littoral zone of a lake or backswamp forest composed of deciduous taxa (Alnus, Populus, Pterocarya, Glyptostrobus; Figs. 5.5 and 5.6) and a few evergreen shrubs (Ilex). Valerianaceae and Osmunda were part of the herb layer. Smilax was a liana growing in wetland forests and thickets as well as well-drained lowland forests. Periodically flooded areas were in close contact to well-drained forests. 5.3.2 Levée Forests, Well-Drained Lowland Forests Including Lakeshore Woodlands A substantial part of the plant remains from the Brjánslækur-Selja Formation are representatives of relatively well-drained rich riparian forests composed of deciduous trees. Levée forests were rarely flooded and composed of fewer species tolerating high ground water tables, while more extensive and diverse woods behind lakeshores and riverbanks thrived on well-drained soils. These latter forests contained elements such as Magnolia, Liriodendron, Sassafras, and possibly Platanus (Fig. 5.6). In addition, trees from neighbouring vegetation types such as maples and Rosaceae were part of these forests. Therefore, these transitional woodlands became more varied with increasing distance from the waterline and gradually changed into more diverse mixed forests on mountain slopes (Fig. 5.4). 5.3.3 Upland Forests Upland forests were rich mixed deciduous-evergreen broadleaved and conifer forests. Conifers formed a substantial part of the foothill forests (Sequoia, Cryptomeria, Abies, Picea, Cathaya, Tsuga) and the montane forests at higher elevations (also Sciadopitys). Large-leaved evergreen rhododendrons were elements of the undergrowth along with Ilex, Lonicera, Viburnum, and Tetracentron. 5.3.4 Other Vegetation Types Two shrubs, Comptonia and Ephedra are at present typical elements of arid regions (Flora of North America Editorial Committee 1993, 1997). Comptonia comprises 5.3 Floras and Vegetation Types Fig. 5.5 Schematic transect of a riparian forest with oxbow lakes and meandering river 245 246 5 The Classic Surtarbrandur Floras (12 Ma) Fig. 5.6 Schematic transect showing lake margin vegetation changing into well-drained lowland and foothill forest 5.4 Changing Environment 247 only a single living species endemic to eastern North America where it grows on sandy and rocky substrates in pine forests, clearings or forest edges. Ephedra is found in Africa, Asia, Europe, North, and South America where it often occurs in dry areas but also in temperate regions. It displays a wide ecological range, growing on rocky substrates but also on flood lands. Overall, this may suggest that, in Iceland, these two elements could have inhabited rocky outcrop forests as well as sandy areas along rivers and shores. 5.4 Changing environment The continuous lava succession below the 12 Ma sedimentary formation suggests high and steady volcanic activity in the region prior to the accumulation of the plant-bearing sediments. Recent basalt lavas in Iceland originate from shield volcanoes or crater rows that are part of large volcanic systems. In the middle of such a system is a central volcano characterized by rhyolitic extrusive rocks (Saemundsson 1979). As the lavas around Vaðalsdalur and Brjánslækur are only basaltic, it is likely that the area was at some distance from a central volcano and that most lavas originated from fissure swarms at the outskirt of a volcanic system. The sediments suggest a sudden termination of lava formation in the region. At the same time, tephra (tuff) layers or pyroclastic beds in the sedimentary succession indicate the presence of an active central volcano. Thin and fine-grained ash layers (fine tuff) suggest relatively long distance origin, but other thick coarse-grained beds (coarse tuff) indicate a closer location to central volcanoes. In any case, it is clear that no lavas were formed during sedimentation, and erosion marked the surface of the uppermost lavas below the sediments. Accumulation of sediments started soon after the termination of lava formation and no apparent hiatus is present. Sediments at Seljá and Surtarbrandsgil suggest that the region was a lowland and highland environment with extensive river systems and several small shallow lakes or ponds and swamps. The lowlands were surrounded by highland hillsides with valleys and volcanic mountains (Fig. 5.4). Initially, the substrate was affected by streams and rivers carrying clastic material from higher elevations to lowland areas. The landscape at Vaðalsdalur-Seljá was marked by streams with channels and deltas formed by meandering rivers running from the highlands towards the sea. After the initial erosion, the sediments became more fine-grained and lakes and ponds formed. As sediments kept accumulating in the area, deltas progressed over shallow lake sediments and fluvial sediments again became prominent. The lowland environment became dominated by a fully developed, complex river system with a surrounding floodplain, oxbow lakes, and swamps. At Brjánslækur-Surtarbrandsgil, a lake basin evolved in a high valley surrounded by hillsides and mountains. In the Brjánslækur area, the palaeotopography is reflected by the varying thickness of the sediments at individual outcrops and the change in sedimentary type. Coarse-grained fluvial sediments are prominent in the beginning of the succession but finer grained sediments of lacustrine origin become more prominent in the 248 5 The Classic Surtarbrandur Floras (12 Ma) middle to upper parts. Initially, streams and rivers shaped the landscape in the Brjánslækur-Surtarbrandsgil region. The accumulation of coarse clastic sediments soon came to a stop and a lake environment became prominent, as reflected by fine clastic sediments and turbidity sandstones. Coarse tuff beds at Surtarbrandsgil indicate closer affinities to an active central volcano than at Seljá. After some time of sedimentation, the whole clastic succession was overlain by a volcanic mixture of hyaloclastic pillow and cube-jointed lava. The thick hyaloclastite and the lava structures (pillow and cube) suggest an underwater eruption and/or lava running into water. The eruption was most likely along a fissure reaching into some of the lakes in the region of Vaðalsdalur and Brjánslækur. At this time, the region again became affected by volcanic activity, forming several lavas that overlay the sedimentary formation. 5.5 ecological and Climatic Requirements of Some Modern Analogues The following section provides information about the ecological and climatic properties of some modern analogues of the taxa present in the 12 Ma BrjánslækurSeljá Formation. Fossil taxa are listed in Table 5.1; all potential modern analogues and their climatic requirements are provided in Appendix 13.1, Chap. 13. For brief descriptions of Glyptostrobus, Sequoia, and Platanus, see in Chap. 4, Sect. 4.4. The monotypic genus Cryptomeria (Cupressaceae s. l.) occurs in southeast China to southern Central China and Japan at elevations from 800 to 2,500 m a. s. l. in its southern range and 50–1,600 m a. s. l. in its northern range (Flora of China Editorial Committee 1999; Iwatsuki et al. 2000). Cryptomeria japonica (Thunb. ex L. f.) D. Don forms part of humid well-drained mixed mesophytic forests sensu Wang (1961), and may occur in wet lowlands in Japan. It is a thermophilous species growing in a Cfa climate (warm temperate-humid-hot summer; Köppen and Geiger 1928; Kottek et al. 2006) with MAT 7–20.5°C. Sciadopitys is a monotypic genus of southern Japan. Sciadopitys verticillata Sieb. and Zucc. occurs at elevations from 700 to 1,200 m a. s. l. (Iwatsuki et al. 2000) and is confined to cool-temperate, mixed evergreen-deciduous forest vegetation, often forming small pure stands. It is a temperate species growing in a Cfa to Dfb (snow, fully humid with warm summers; Köppen and Geiger 1928; Kottek et al. 2006) climate with MAT 7.4–16.6°C (MAT from Utescher and Mosbrugger 2009). The fossil species Alnus gaudinii is morphologically very similar to the Caspian endemic A. subcordata C. A. Mey. and the Japanese A. japonica Sieb. and Zucc. Alnus subcordata occurs at elevations from 0 to 1,500 m a. s. l. in deciduous broadleaved forests, and along streams. It thrives in a Cfa to Csa climate (Köppen and Geiger 1928; Kottek et al. 2006), with MAT 7.2–18.6°C. Alnus japonica has a vast distribution in East Asia, occurring in the Russian Far East, China, Korea, Japan, and Taiwan (Komarov 1970; Flora of China Editorial Committee 1999). It is an element of temperate forests, lake shores, and stream banks with an altitudinal 5.5 Ecological and Climatic Requirements of Some Modern Analogues 249 range from 0 to 1,500 m a. s. l. (Ohwi 1965). In accordance with its large distribution range, this species grows under a Cfa, Cwa (warm temperate, fully humid or winter dry, with hot summers), Dwa (snow, winter dry with hot summers), and Dwb climate (snow, winter dry with warm summers; Köppen and Geiger 1928; Kottek et al. 2006) with MAT 0.2–24.4°C. The fossil Betula islandica falls within the variability of the modern section Costatae (Regel) Koehne based on its leaf size and type of fruit scales. Within the section Costatae, B. islandica shows similarities to the Eurasian species B. utilis D. Don and B. ermanii Cham. In addition, the unrelated (see Schenk et al. 2008) B. papyrifera Marshall has leaves that are fairly similar to Betula islandica. Betula ermanii is distributed in northeastern China, Japan, North Korea, and Russia (Kamchatka). It forms pure forest stands or is part of mixed coniferous and broadleaved forests between 1,000 and 1,700 m a. s. l. Betula utilis has a range from Afghanistan, India, Nepal and Bhutan to temperate areas in western and Central China. This species grows in temperate broad-leaved forests at elevations between 2,500 and 3,800 m a. s. l. (Flora of China Editorial Committee 1999). Betula papyrifera is an element of rather moist forests on slopes or in swampy areas; it occurs from 300 to 900 m a. s. l. (Flora of North America Editorial Committee 1997). While B. papyrifera grows in Dfb and Dfc climates with MAT ranging from −12.2°C to 11.4°C (Thompson et al. 1999), B. ermannii and B. utilis thrive under winter dry Cwb and Dwa, Dwb, Dwc climates with MAT −7 to 14.6°C and −0.4 to 22.5°C, respectively. Sassafras comprises only three species today displaying an East Asian-North American disjunction. Sassafras tzumu (Hemsl.) Hemsl. occurs in temperate and subtropical regions of China; it grows in light or dense forests from 100 to 1,900 m a. s. l. Sassafras randaiense (Hayata) Rehder is endemic to Taiwan and grows in evergreen broad-leaved forests between 900 and 2,400 m a. s. l. (Flora of China Editorial Committee 1999). Sassafras albidum (Nutt.) Nees occurs in eastern North America in temporally flooded to well-drained forests and disturbed areas from 0 to 1,500 m a. s. l. All three species are typical of a Cfa and Cfb climate with MAT from 6.7°C to 20.6°C (S. albidum) and 8.4–19.8°C (S. tzumu). Liriodendron consists of only two modern species, L. tulipifera L. in North America and L. chinensis Sarg. in Central China. Liriodendron tulipifera is restricted to eastern North America where it is an element of rich woodlands, bluffs, low mountains, and hills (Flora of North America Editorial Committee 1997); it grows from 0 to 1,500 m a. s. l. under a Cfa climate with MAT from 4.4°C to 22°C (Thompson et al. 1999). Liriodendron chinensis is native to central and southern China, where it thrives under a Cfa climate with MAT from 11°C to 18°C. Oswald Heer (Heer 1868, pp. 70–71) previously used the fossil species Liriodendron procaccinii as a key taxon to estimate the climate of the Miocene in Iceland. He compared the fossil species to the modern L. tulipifera from eastern North America. Using the distribution limits of fruiting cultivated L. tulipifera in Europe, he concluded that the mean annual temperature (MAT) for Iceland was at least 11.5ºC during the Miocene. Comptonia peregrina (L.) J. M. Coult. is another species endemic to eastern North America. It is a small shrub on dry, sandy to rocky substrates in pine forests, 250 5 The Classic Surtarbrandur Floras (12 Ma) clearings, or forest edges; it occurs from 0 to 1800 m a. s. l. with MAT from 3.4°C to 15.6°C (MAT from Utescher and Mosbrugger 2009). Its distribution range covers various climate types; warm temperate, fully humid, with hot or warm summers, i.e. Cfa and Cfb climates, to snow, fully humid, with hot and warm summers, i.e. Dfa and Dfb climates (Köppen and Geiger 1928; Kottek et al. 2006). During the Tertiary, Comptonia was a common element across the entire northern hemisphere which makes it difficult, based on a single living species, to draw conclusions about the ecological requirements of fossil representatives (Mai 1995). Overall, both the macrofossil and the palynological records are suggestive of humid warm temperate conditions (Cfa climate) in the lowlands (Glyptostrobus, Platanus, Sassafras) and a slightly cooler climate in the uplands (Cfb climate). The temperature requirements (MAT) of the taxa encountered in the ca 12 Ma floras are between 9°C and 14°C for upland environments and up to ca 15°C for lowland riparian elements such as Glyptostrobus (Appendix 13.1, Chap. 13). Available evidence suggests that the climate was similar to the one estimated for the 15 Ma formation. 5.6 Taxonomic Affinities and origin of the Middle Serravallian Floras Most of the plant taxa recorded for the 12 Ma formation have related fossil species and potential modern analogues in all three northern temperate regions (Eastern Asia, Europe and Asia Minor, North America). For example, the genera Sassafras and Liriodendron that are restricted to the 12 Ma sedimentary rock formation in Iceland, occurred across the whole northern hemisphere during the Tertiary (Mai 1995; Manchester 1999) and display an East Asian-eastern North American disjunct distribution at present. Other taxa with a present northern hemisphere disjunct distribution that appear for the first time in the 12 Ma sedimentary formation in Iceland are, among others, Acer askelssonii (modern Acer section Acer), A. crenatifolium (modern Acer section Rubra; see Chap. 3), Carya, Laurophyllum (Lauraceae), Corylus, and Lonicera. One taxon, endemic to North America at present, Comptonia, is not indicative of floral affinities, since it was a widespread element in the European Tertiary (Mai 1995) and was possibly a component of high latitude floras until the Early Pliocene (Seward Peninsula, Alaska; Matthews and Ovenden 1990). In contrast, a small number of plant taxa are strong indicators for either migration from Eurasia or North America. Among conifers, Cryptomeria and Sciadopitys are restricted to East Asia at present but were widespread in the European Tertiary (Mai 1995; Manchester et al. 2009). Both genera have an ambiguous fossil record for North America (Aulenback and LePage 1998; Manchester et al. 2009; but see Matthews and Ovenden 1990, who reported Sciadopitys from the Pliocene of the Devon and Meighen islands). Overall, this points to a European rather than North American origin. The same may be true for Alnus gaudinii which is morphologically most similar to various Eurasian modern species and was a typical element of the European Tertiary (Kvaček et al. 2002; Denk et al. 2005). 5.7 Transitional Phase 15–12 Ma: Iceland, Arctic North America and Europe 251 5.7 Transitional Phase 15–12 Ma: Iceland, Arctic north America and europe From the Late Oligocene to the Middle Miocene (ca 27–15 Ma), a global warming trend reduced the Antarctic ice sheet and global ice volume remained low. This warm phase culminated in the Mid-Miocene Climatic Optimum (ca 17–15 Ma; Zachos et al. 2001) and was followed by gradual cooling associated with a re-establishment of the Antarctic ice sheet. This global trend has been recorded in various floras across the northern hemisphere. White et al. (1997) studied pollen and spore assemblages from the western part of Arctic North America covering the past 18 Ma. In these palynological records, a global warm peak ca 15 Ma (Seldovian Stage) is shown by the abundance of thermophilous taxa, including Fagus and Quercus. The subsequent Homerian Stage (13–8 Ma) is characterized by markedly cooler conditions reflected by the absence of warmth-loving taxa (TaxodiaceaeCupressaceae-Taxaceae, Fagaceae, Cercidiphyllum, Ilex, Nyssa, Liquidambar, Tilia, Acer). The last occurrence of some warmth-loving taxa is recorded at 13.5 Ma, marked by a decline in the percentage of Ulmus-type pollen. The pattern of dramatic cooling after 15 Ma is congruent with the marine d18O decline and sea level fall after 14.8 Ma (Flower and Kennett 1994; Zachos et al. 2001). A mid-latitude North American example for a late Middle to early Late Miocene flora is the Stinking Water flora from southeastern Oregon (Chaney and Axelrod 1959; K-Ar date 12–11 Ma, Armstrong et al. 1975; Appendix 5.1). Compared to the ca 15 Ma Clarkia flora (see Chap. 4), taxa belonging to Magnoliaceae and Lauraceae (Magnolia, Liriodendron, Lindera, Persea, and Sassafras) are present in the Clarkia flora but are absent from the younger Stinking Water flora. This may indicate regional floristic changes and extinction events across the time span 15–12 Ma. The Clarkia flora also comprises other warmthloving elements such as Diospyros (Ebenaceae), Gordonia (Theaceae), Gleditsia (Fabaceae), and Symplocos (Symplocaceae) that have not been recorded for the Stinking Water flora. In addition, the Clarkia flora contains extinct taxa such as Zizyphoides-Nordenskioldia, Palaeocarya, and Pseudofagus, all missing in the Stinking Water flora. This could possibly indicate the extinction of these taxa in the region between 16–15 and 12 Ma. In Iceland, no such conspicuous change as seen in the North American Arctic and partly mid-latitude floras across the transition 15–12 Ma can be observed. Taxodiaceae are abundant in the sedimentary rocks of the 12 Ma BrjánslækurSeljá Formation and several warmth-loving angiosperms occur for the first time in the fossil record of Iceland (Sassafras, Liriodendron, Laurophyllum, Dicotylophyllum aff. Neolitsea) or persist from the 15 Ma Selárdalur-Botn Formation (Magnolia, Platanus). A possible explanation for this deviating pattern is given in Chap. 13. For Europe, Kovar-Eder and Kvaček (2007) and Kovar-Eder et al. (2008) compared vegetation types for different time slices from which well-dated floras exist. For the time interval 17–14 Ma, subtropical broad-leaved evergreen forests and 252 5 The Classic Surtarbrandur Floras (12 Ma) partly subtropical subhumid xerophyllous forests are recorded for the western and southwestern parts of Europe. Warm temperate broad-leaved deciduous and partly mixed mesophytic forests dominated from the Carpathians eastwards. In general, broad-leaved evergreen forests had a wide north-south distribution, extending as far as Jutland (Denmark). In contrast, for the time interval 12–8.5 Ma, warm temperate broad-leaved deciduous forests and mixed mesophytic forests were characteristic of Central Europe and extended as far as Spain. At the same time, subtropical broadleaved evergreen forests became much less common and were restricted to favourable regions. Kovar-Eder et al. (2008) state that the wide distribution of broad-leaved evergreen forests and mixed mesophytic forests during the period 17–14 Ma reflects the Mid-Miocene Climatic Optimum. The subsequent spread of mixed mesophytic and broad-leaved deciduous forests is directly linked to long-term cooling after 15 Ma. At the same time, a regional differentiation is seen for the period 17–14 Ma with warmer conditions in western and central Europe compared to cooler conditions further east. Humidity was lower in the western part of Europe (reflected by the higher proportion of sclerophyllous types and Fabaceae) but higher in the central and eastern regions. During the period 12–8.5 Ma, the climate was markedly cooler and more humid in large parts of Europe. A rich flora that is similar in age to the Icelandic Surtarbrandur floras comes from eastern Ukraine (Krynka, Kryshtofovich and Baikovskaya 1965; part of “Florenkomplex Kosov-Krynka”, Mai 1995). The late Badenian (ca 13 Ma) Krynka flora was dominated by broad-leaved deciduous taxa with a small component of evergreen elements (Magnoliaceae, Lauraceae, Ericaceae, Buxus, Ilex). Among the broad-leaved deciduous taxa, Fagaceae, Betulaceae, Rosaceae, and Sapindaceae (Acer) were most prominent, but Juglandaceae and Ulmaceae were also characteristic elements of this flora. An interesting (perhaps regional) feature of this and other eastern European floras of the Florenkomplex Kosov-Krynka is the complete lack of Cupressaceae (incl. Taxodiaceae) and Pinaceae (Mai 1995). While sharing a number of genera with the Icelandic floras, the Krynka flora contains various warmth-loving elements typical of mid-latitude floras across the northern hemisphere that never reached Iceland (Fabaceae, Rutaceae, Simarubaceae, Anacardiaceae, Nyssaceae and others; see Appendix 5.1). The late Sarmatian (ca 12–11.6 Ma) macroflora of Armavir (southwestern Russia; Kutuzkina 1964; Mai 1995) is geographically close to the Krynka flora and reflects broadleaved deciduous vegetation that contained a number of warmth-lowing elements typical of mid-latitudes that never reached Iceland. Examples are Berberidaceae, Lauraceae (one single record in the Surtarbrandsgil locality), Fabaceae, and Hamamelidaceae. At the same time, a number of taxa found in the Armavir flora are also present in the 10, 12, and 15 Ma formations of Iceland. Examples are Ginkgo, Cyclocarya, Platanus, Pterocarya, and Rhododendron ponticum type. According to Kutuzkina (1964) the Armavir flora contains a number of “modern” Eastern Mediterranean-Caucasian and Submediterranean elements (Periploca, Punica, Pyracantha coccinea, Cotinus coggyria, Ligustrum sp.; Appendix 5.1). This may reflect environmental changes related to global cooling (and regionally drier conditions). 5.8 Summary 253 In a more regional study, Kvaček et al. (2006) examined the changes in vegetation and climate types over the time period 17–16 Ma to 12 Ma in the Central Paratethys. During the time interval 17–16 Ma, subtropical broad-leaved forests with a substantial proportion of evergreen elements were common in the western parts, whereas mixed mesophytic and broad-leaved deciduous forests were more common near the mountains in the northern and central parts of the Central Paratethys. A general cooling and more pronounced climatic gradient between the northern and southern parts of the Central Paratethys was observed for the 12 Ma time slice. This is in accordance with the pattern observed by Kovar-Eder and Kvaček (2007). 5.8 Summary In this chapter, an updated list of plant taxa based on macrofossils, pollen and spores is provided for the 12 Ma Brjánslækur-Seljá Formation. The fossil flora of this period is the most exotic one recorded for the Miocene in Iceland and contains taxa such as Ephedra, Liriodendron, Comptonia, Smilax, Laurophyllum and warmth-loving elements from older floras (Cathaya, Cryptomeria, Glyptostrobus, Sequoia, Magnolia, Platanus). The vegetation was diverse with lowland riparian and well-drained forests and upland forests. Ephedra, Comptonia and herbaceous taxa such as Sanguisorba may have inhabited more open places on rocky substrates. Overall, the flora is a typical northern hemispheric Miocene flora. Elements that appear for the first time in the 12 Ma formation could have colonized Iceland both from the west and from the east. The palaeoclimate inferred from potential modern analogues was humid warm temperate and is best described as a Cfa (to Cfb) climate according to Köppen. Global ice volume had remained low during the Late Oligocene and Early Miocene. This warm phase peaked in the Mid-Miocene Climatic Optimum (ca 17–15 Ma) and was followed by cooling due to the reestablishment of the Antarctic ice sheet. While this global cooling trend is also seen in fossil floras of Arctic North America and Europe, in Iceland markedly warm conditions persisted until 12 Ma. 254 5 The Classic Surtarbrandur Floras (12 Ma) Appendix 5.1 Floristic composition of the 12 Ma sedimentary formation of Iceland compared to contemporaneous northern hemispheric mid-latitude floras from North America and western Eurasia. Brjánslækur-Seljá flora, Iceland [ca 65°31¢ n 23°12¢ W] 12 Ma This study 3 Equisetum sp. 1 Hepaticae gen. et spec. indet. 1 Lycopodium sp. 1, 3 Osmunda parschlugiana 1 1 1 1 1-3 1, 3 1, 3 1 1-3 1 1 1 1, 3 1-3 1-3 1 1-3 1-3 1-3 1-3 1-3 1 2 3 3 Polypodiaceae gen. et spec. indet. 1 Polypodiaceae gen. et spec. indet. 2 Trilete spore fam. gen. et spec. indet. 1 Ephedra sp. Abies steenstrupiana Cathaya sp. Cryptomeria anglica Glyptostrobus sp. Picea sect. Picea Pinus sp. 1 Sciadopitys sp. Sequoia sp. Tsuga sp. Acer askelssonii Acer crenatifolium subsp. islandicum aff. Cedrelospermum sp. Alnus cecropiifolia Alnus gaudinii Betula islandica Carpinus sp. MT1 Carpinus sp. MT2 Carya sp. cf. Fraxinus sp. cf. Juglans Comptonia hesperia 1, 3 Corylus sp. 1 1 1 3 1 3 1, 3 3 3 1 1 1 1 1 1 1 1 1, 2 1, 3 1 1 1, 3 1, 3 1, 3 1-3 1 3 3 1 3 1 1 Cyperaceae gen. et spec. indet. A Dicotylophyllum sp. A Ilex sp. 1 Laurophyllum sp. (Laurus) Lemna sp. Liriodendron procaccinii Lonicera sp. 1 Magnolia sp. Phragmites sp. Platanus sp. Pollen type 1 Pollen type 2 Pollen type 3 Pollen type 4 Pollen type 5 Pollen type 6 Pollen type 7 Populus sp. A (ex group P. tremula L.) Pterocarya sp. Rhododendron sp. 1 Rhododendron sp. 2 Rosaceae gen et. spec. indet. A Rosaceae gen et. spec. indet. B Rosaceae gen et. spec. indet. C Salix gruberi Sanguisorba sp. Sassafras ferrettianum Smilax sp. Tetracentron atlanticum Ulmus cf. pyramidalis Valerianaceae gen. et spec. indet. Viburnum sp. 1, 3 aff. Calycanthaceae Appendix 5.1 Stinking Water flora [ca 44°n 118°W] 12-11 Ma (K-Ar) Chaney, 1959 1 Polypodiaceae 1 ephedra sp. 1, 3 Abies chaneyi Mason 1 Cedrus sp. 1 Cupressaceae/Taxodiaceae/Taxaceae 3 Glyptostrobus oregonensis Brown 3 Keteleeria heterophylloides (Berry) Brown 1, 3 Picea lahontense MacGinitie 1, 3 Picea magna MacGinitie 1, 3 Picea sonomensis Axelrod 1, 3 Pinus harneyana Chaney 1 Tsuga sp. 1, 3 Acer bendirei Lesquereux 1, 3 Acer bolanderi Lesquereux 1, 3 Acer columbianum Chaney 1, 3 Acer minor Knowlton 1, 3 Acer oregonianum Knowlton 1, 3 Acer scottiae MacGinitie 3 Ailanthus indiana (MacGinitie) Brown 1, 3 Alnus harneyana Chaney 1, 3 Alnus hollandiana Jennings 1, 3 Alnus relatus (Knowlton) Brown Asteraceae 1 1 Betula sp. 1 Carya sp. 1 Caryophyllaceae/Chenopodiaceae 3 Cedrela trainii Arnold 1 Celtis sp. 1 1 1 1 3 3 1 1 3 3 1 1 1 1, 3 3 1, 3 3 1, 3 1, 3 1, 3 1, 3 1, 3 1, 3 3 1, 3 1, 3 1, 3 3 1, 3 1, 3 Corylus sp. ericaceae Fagus sp. 255 Fraxinus sp. Gymnocladus dayana (Knowlton) Chaney Hydrangea bendirei (Ward) Knowlton Juglans sp. Liquidambar sp. Mahonia reticulata (MacGinitie) Brown Mahonia simplex (Newberry) Arnold Nyssa sp. Onagraceae Ostrya sp. Platanus dissecta Lesquereux Populus lindgreni Knowlton Potamogeton parva Brown Ptelea miocenica Berry Pterocarya mixta (Knowlton) Brown Quercus dayana Knowlton Quercus hannibali Dorf Quercus prelobata Condit Quercus pseudolyrata Lesquereux Quercus simulatea Knowlton Rosa harneyana Chaney Salix hesperia (Knowlton) Condit Salix succorensis Chaney Smilax magna Chaney Spiraea harneyana Chaney Typha lesquereuxi Cockerell Ulmus speciosa newberry 256 Krynka flora [ca 47°30 ¢ n 38°35¢ e] Latest Badenian, “Presarmatian” Kryshtofovich and Baikovskaya 1965; Mai 1995 3 3 2, 3 Acer compositifolium Baik. Acer pseudomiyabei Baik. Acer pseudoplatanus L. var. paucidentata Gaud. Acer sp. Acer sp. cf. A. platanoides L. Acer subcampestre Goepp. var. acuminatolobatum Baik. Acer subcampestre Goepp. var. integrilobifolium Baik. Acer subcampestre Goepp. var. macrophyllum Baik. Ailanthus confucii Ung. Alnus kefersteinii (Goepp.) Ung. Alnus sp. Berberis longaepetiolata Baik. Betula grandifolia ett. Betula sp. Betula tanaitica Baik. Bumelia sp. Buxus pliocenica Sap. et Mar. Carex sp. Carpinus cf. laxiflora Bl. Carpinus grandis Ung. Carpinus marmaroschia Iljinskaja Carya denticulata (Web.) Iljinskaja Celtis trachytica Ett. Ceratophyllum sniatkovii Krysht. Cercis turgaica Usnadze Clerodendron ovalifolium Baik. Clethra maximoviczii Nath. Cornus attenuata Ett. Cornus cf. acuminata Web. Cornus megaphylla Hu et Chaney Cornus oeningensis (Heer) Baik. Cornus studeri Heer Corylus insignis Heer Cotoneaster sp. cf. C. andromedae Ung. Crataegus praemonogyna Krysht. Daphne limnophylla (Ung.) Baik. Diospyros brachysepala A. Br. Elaeagnus sp. Eucommia palaeoulmoides Baik. Fagus orientalis var. fossilis (Lipsky) Palibin Fagus sp. Genista sp. Hibiscus splendens Baik. Hovenia thunbergii (Nath.) Baik. Hydrangea sp. Ilex falsanii Sap. et Mar. Juglans zaisanica Iljinskaja Laburnum sp. 5 The Classic Surtarbrandur Floras (12 Ma) 3 3 3 2 3 3 3 3 3 3 3 2, 3 2, 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 2 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 2 3 3 2 3 3 3 3 3 Laurocerasus sp. Leguminosae sp. Ligustrum vulgare L. var. fossile Palib. Liquidambar sp. Lonicera sp. A Lonicera sp. B Loranthus sp. Magnolia cf. M. dianae Ung. Magnolia cuneifolia Baik. Magnolia sp. Mespilus sp. Nyssa vertumnii Ung. Ostrya kryshtofovichii Baik. Paliurus sp. Parrotia pristina (Ett.) Stur Photinia acuminata Baik. Physocarpus sp. Pistacia cf. P. miocenica Sap. Polygonum ukrainicum Baik. Populus balsamoides Goepp. Prunus palaeocerasus Ett. Pyracantha sp. Pyrus sarmatica (Krysht.) Baik. Quercus pseudocastanea Goepp. Quercus pseudorobur Kov. Quercus sp. A Quercus sp. B Ranunculus sp. Rhododendron megiston Ung. Rhododendron sp. Rhus noeggerathii Weber Rosa lignitum Engelhardt (non Heer) Rubus palaeohirtus Baik. Salix media A. Braun Salvinia natanella Shap. Sambucus palaeoracemosa Baik. Sapindus cupanioides Ett. Sassafras ferretianum Massal. Schisandra sp. Skimmia sp. Spiraea sp. Staphylea cf. pinnata L. Styrax protoobassia (Nath.) Tanai et Onoe Styrax pseudoofficinale Baik. Styrax sp. Tilia sp. Ulmus carpinoides Goepp. Ulmus longifolia Ung. Ulmus sp. Vaccinium pseudouliginosum Krysht. Vitis praevinifera Sap. Vitis sp. Vitis subintegra Sap. Zelkova ungeri Kov. 3 2, 3 3 3 3 3 3 3 3 3 2 3 3 3 2 2 2, 3 2 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 2 2 3 3 3 3 3 3 Appendix 5.1 Armavir flora [ca 45°00’ n 41°07’ e] Middle/Late Sarmatian Kutuzkina 1964; Mai 1995 3 Pteridium sp. 3 2 3 2 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 Ginkgo adiantoides (Ung.) Heer Pinus sp. Acer decipiens A. Br. Acer sp. Alnus kefersteinii (Goepp.) Ung. Amelanchier sp. cf. A. rotudifolia (Lam.) Dum.-Cours. Berberis sp. Betula sp. Bumelia sp. (cf. B. lanuginosa (Michx.) Pers.) Calycanthus sp. (cf. C. florida L.) Carpinus grandis Ung. Carya serrifolia (Goepp.) Kräusel Carya sp. Castanea atavia Unger Celastrus palibinii Kutuzk Cercidiphyllum crenatum (Ung.) R. W. Brown Cinnamomum cf. lanceolatum (Ung.) Heer Cinnamomum polymorphum (A. Br.) Heer Clematis sp. Cornus cf. sanguinea L. Cornus sp. Corylus sp. Cotinus coggygria Scop. Cyclocarya cycloptera (Schlecht.) Iljinskaja Diospyros brachysepala A. Br. Fagus orientalis Lipsky fossilis Palibin Fraxinus inaequalis Heer Fraxinus grossidentata Laurent Gleditsia allemanica Heer Hamamelis miomollis Hu et Chaney Juglans acuminata A. Br. Laurus sp. Leguminosites sp. Ligustrum sp. (cf. L. vulgare L.) Liquidambar europaea B. Br. Liquidambar sp. 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 2 2 2 2 2 2 2 2 2 257 Loranthus palaeoeuropaeus Kutuzk Myrica laevigata (Heer) Sap. Myrica lignitum (Ung.) Sap. Myrica palaeogale Pilar Parrotia pristina Ett. Periploca angustifolia Kutuzk. Phragmites oeningensis A. Br. Phyllites sp. Phyllites sp. (cf. Ilex fargesii Franch.) Platanus lineariloba Kolak. Podogonium knorrii Heer Populus balsamoides Goepp. Populus latior A. Br. Prunus sp. Pterocarya castaneifolia (Goepp.) Schlecht. Punica granatum L. Pyracantha coccinea Roem. Quercus castaneifolia C. A. Mey. var. fossilis Quercus neriifolia A. Br. Quercus pseudorobur Kov. Rhododendron sp. (cf. R. ponticum L.) Rhus blitum Sap. Robinia regelii Heer Rosa sp. Salix angusta A. Br. Salix integra Goepp. Salix varians Goepp. Typha latissima A. Br. Ulmus carpinoides Goepp. Ulmus longifolia Ung. Vaccinium protoarctostaphylos Kolak. Vitis sp. Zelkova ungeri Kov. Zizyphus sp. Boldface indicates that the genus is present in the Brjánslækur-Seljá Formation. Grey shading indicates that the genus is present in the older Selárdalur-Botn Formation (15 Ma). 1 based on pollen, spores; 2 based on leaves and/ or fruit/seed fossils; 3 based on leaf fossils 258 5 The Classic Surtarbrandur Floras (12 Ma) References Akhmetiev, M. A., Bratzeva, G. M., Giterman, R. E., Golubeva, L. V., & Moiseyeva, A. I. (1978). Late Cenozoic stratigraphy and flora of Iceland. Transactions of the Academy of Sciences USSR, 316, 1–188. Armstrong, R. L., Lemann, W. P., & Malde, H. E. (1975). K-Ar dating, Quaternary and Neogene volcanic rocks of the Snake River Plain, Idaho. American Journal of Science, 274, 225–252. Aulenback, K. R., & LePage, B. A. (1998). Taxodium wallisii sp. nov. – First occurrence of Taxodium from the Upper Cretaceous. International Journal of Plant Sciences, 159, 367–390. Berggren, W., Kent, D. V., Swisher, C. C. III., & Aubry, M.-P. (1995). A revised Cenozoic geochronology and chronostratigraphy. In W. A. Berggren, D. V. Kent, M.-P. Aubry, & J. Hardenbol (Eds.), Geochronology, time scales and global stratigraphic correlation (pp. 129–212). Tulsa, Oklahoma: SEPM Special Publication 54. Chaloner, B. W. (1999). Plant and spore compression in sediments. In T. P. Jones & N. P. Rowe (Eds.), Fossil plants and spores: modern techniques (pp. 36–40). London: Geological Society. Chaney, R. W., & Axelrod, D. I. (1959). Miocene Floras of the Columbia Plateau. Part II. Systematic Considerations (part II, pp. 135–237). Washington, DC.: Carnegie Institution of Washington Publication 617. Denk, T., Grímsson, F., & Kvaček, Z. (2005). The Miocene floras of Iceland and their significance for late Cainozoic North Atlantic biogeography. Botanical Journal of the Linnean Society, 149, 369–417. Flora of China Editorial Committee. (1999). Flora of China, Cycadaceae through Fagacaeae (Vol. 4). St. Louis: Missouri Botanical Garden Press. 453 pp. Flora of North America Editorial Committee. (1993). Flora of North America North of Mexico, Pteridophytes and Gymnosperms (Vol. 2). New York: Oxford University Press. 496 pp. Flora of North America Editorial Committee. (1997). Flora of North America North of Mexico, Magnoliophyta: Magnoliidae and Hamamelidae (Vol. 3). New York: Oxford University Press. 616 pp. Flower, B. P., & Kennett, J. P. (1994). The middle Miocene climatic transition: East Antarctic ice sheet development, deep ocean circulation and global carbon cycling. Palaeogeography, Palaeoclimatology, Palaeoecology, 108, 537–555. Friedrich, W. L. (1966). Zur Geologie von Brjánslaekur (Nordwest-Island) unter besonderen Berücksichtigung der fossilen Flora. Sonderveröffentlichungen des Geologischen Institutes der Universität Köln, 10, 1–110. Friedrich, W. L., & Símonarson, L. A. (1981). Die fossile Flora Islands: Zeugin der ThuleLandbrücke. Spektrum der Wissenschaft, 10(1981), 22–31. Grímsson, F. (2007). The Miocene floras of Iceland. Origin and evolution of fossil floras from North-West and Western Iceland, 15 to 6 Ma. Ph.D. thesis, University of Iceland, Reykjavík. 273 pp. Heer, O. (1868). Flora fossilis arctica 1. Die Fossile Flora der Polarländer enthaltend die in Nordgrönland, auf der Melville-Insel, im Banksland, am Mackenzie, in Island und in Spitzbergen entdeckten fossilen Pflanzen. Zürich: F. Schulthess. 192 pp. Iwatsuki, K., Yamazaki, T., Boufford, D. E., & Ohba, H. (Eds.). (2000). Flora of Japan. Vol. 1 Pteridophyta and Gymnospermae. Tokyo: Kodansha. 302 pp., reprint of 1995. Jóhannesson, H., & Sæmundsson, K. (1989). Geological map of Iceland. 1:500 000. Bedrock Geology (1st ed.). Reykjavík: Icelandic Museum of Natural History and Icelandic Geodetic Survey. Komarov, V. L. (1970). Flora of the U.S.S.R (Vol. 5). Jerusalem: Israel Program for Scientific Translations. 593 pp. Köppen, W., & Geiger, R. (1928). Klimakarte der Erde. Wall-map 150 cm × 200 cm. Gotha: Verlag Justus Perthes. Kottek, M., Grieser, J., Beck, C., Rudolf, B., & Rubel, F. (2006). World map of the Köppen-Geiger climate classification updated. Meteorologische Zeitschrift, 15, 259–263. References 259 Kovar-Eder, J., & Kvaček, Z. (2007). The integrated plant record (IPR) to reconstruct Neogene vegetation: the IPR-vegetation analysis. Acta Palaeobotanica, 47, 391–418. Kovar-Eder, J., Jechorek, H., Kvaček, Z., & Parashiv, V. (2008). The integrated plant record: an essential tool for reconstructing Neogene zonal vegetation in Europe. Palaios, 23, 97–111. Kryshtofovich, A. N., & Baikovskaya, T. I. (1965). Sarmatian flora of Krynka. MoscowLeningrad: Russian Academy of Sciences. 134 pp. Kutuzkina, E. F. (1964). The Sarmatian Flora of Armavir (in Russian). In A. L. Takhtajan (Ed.), Palaeobotanica V (pp. 145–230). Moscow-Leningrad: Nauka. Kvaček, Z., Velitzelos, D., & Velitzelos, E. (2002). Late Miocene flora of Vegora Macedonia N. Greece. Athens: Korali Publications. 175 pp. Kvaček, Z., Kováč, M., Kovar-Eder, J., Doláková, N., Jechorek, H., Parashiv, V., Kováčová, M., & Sliva, L. (2006). Miocene evolution of landscape and vegetation in the Central Paratethys. Geologica Carpathica, 57, 295–310. Landmælingar Íslands. (1984). Uppdráttur Íslands. Blað 13, Barðaströnd. Scale 1:100000. Mai, H. D. (1995). Tertiäre Vegetationsgeschichte Europas. Jena: Gustav Fischer. 691 pp. Manchester, S. R. (1999). Biogeographical relationships of North American Tertiary floras. Annals of the Missouri Botanical Garden, 86, 472–522. Manchester, S. R., Chen, Z.-D., Lu, A.-M., & Uemura, K. (2009). Eastern Asian endemic seed plant genera and their paleogeographic history throughout the Northern Hemisphere. Journal of Systematics and Evolution, 47, 1–42. Matthews, J. F., Jr., & Ovenden, L. E. (1990). Late Tertiary Plant Macrofossils from localities in Arctic/Subarctic North America: a review of the data. Arctic, 43, 364–392. McDougall, I., Kristjansson, L., & Saemundsson, K. (1984). Magnetostratigraphy and geochronology of northwest Iceland. Journal of Geophysical Research, 89, 7029–7060. Ohwi, J. (1965). Flora of Japan. Washington, DC: Smithsonian Institution. 1067 pp. Saemundsson, K. (1979). Outline of the geology of Iceland. Jökull, 29, 7–28. Schenk, M. F., Thienpont, C.-N., Koopman, W. J. M., Gilissen, L. J. W. J., & Smulders, M. J. M. (2008). Phylogenetic relationships in Betula (Betulaceae) based on AFLP markers. Tree Genetics and Genomes, 4, 911–924. Thompson, R. S., Anderson, K. H., and Bartlein, P. J. (1999). Atlas of relations between climatic parameters and distribution of important trees and shrubs in North America-Hardwoods. U.S. Geological Survey Professional Paper, 1650-B, 1–423. Utescher, T., & Mosbrugger, V. (2009). Palaeoflora database. http://www.geologie.unibonn.de/ Palaeoflora. Accessed 27 September 2010. Wang, C.-W. (1961). The forests of China, with a survey of grassland and desert vegetation. Maria Moors Cabot Foundation, Publ. No. 5. Cambridge, Massachusetts: Harvard University. 282 pp. White, J. M., Ager, T. A., Adam, D. P., Leopold, E. B., Giu, G., Jetté, H., & Schweger, C. E. (1997). An 18 million year record of vegetation and climate change in northwestern Canada and Alaska: tectonic and global climatic correlates. Palaeogeography, Palaeoclimatology, Palaeoecology, 130, 293–306. Windisch, P. (1886). Beiträge zur Kenntnis der Tertiärflora von Island. Inaugural-Dissertation behufs Erlangung der philosophischen Doctorwürde der Hohen philosophischen Facultät der Universität Leipzig. Halle a. d. S.: Gebauer-Schwetschke’sche Buchdruckerei. 52 pp. Windisch, P. (1886b). Beiträge zur Kenntniss der Tertiärflora von Island. Zeitschrift für Naturwissenschaften, 4(5), 215–262. Worm, O. (1655). Museum Wormianum seu historia rerum rariorum. Leiden, Amsterdam: Ex officina Elseviriorum. 389 pp. Zachos, J. C., Pagani, M., Sloan, L., Thomas, E., & Billups, K. (2001). Trends, rhythms, and aberrations in global climate 65 Ma to present. Science, 292, 686–693. 260 5 The Classic Surtarbrandur Floras (12 Ma) explanation of Plates Plate 5.1 1–4. Seljá in Vaðalsdalur, Northwest Iceland, Brjánslækur-Seljá Formation (ca 12 Ma). 1. View of the Seljá outcrop, sediments on the right side of the stream. 2. Clastic sediments, diatomite at the base, siltstones above. 3. Detail of sandstones and ash layers. 4. Fossils preserved as red rusty impressions in white diatomite. 5–8. Surtarbrandsgil at Brjánslækur, Northwest Iceland, Brjánslækur-Seljá Formation (ca 12 Ma). 5. A look down the gully Surtarbrandsgil, sediments in middle of photo. 6. The Surtarbrandsgil outcrop, note person standing on the mid left for scale. 7. Lake deposited sedimentary rocks, including diatomite rich siltstones and sandstones, and occasional ash layer. 8. Fossils preserved as compressions, revealed as part and counterpart, with the black organic plant material on one part and a diatomite crust on the counterpart Plate 5.2 1–3. Trilete spore fam. gen. et spec. indet. 1. 1. Spore in SEM, distal polar view. 2. Detail of spore surface. 3. Spore in LM, polar view. 4–6. Polypodiaceae gen. et spec. indet. 2. 4. Spore in SEM, equatorial view. 5. Detail of spore surface. 6. Spore in LM, equatorial view. 7–9. Hepaticae gen. et spec. indet. 7. Spore in SEM, proximal polar view showing trilete tetrad mark. 8. Detail of spore surface. 9. Spore in LM, proximal polar view. 10–12. Lycopodium sp. 10. Spore in SEM, distal polar view. 11. Detail of spore surface. 12. Spore in LM, distal polar view. 13– 15. Lycopodium sp. 13. Spore in SEM, distal polar view. 14. Detail of spore surface. 15. Spore in LM, proximal polar view, showing trilete tetrad mark. 16–18. Polypodiaceae gen. et spec. indet. 1. 16. Spore in SEM, equatorial view. 17. Detail of spore surface. 18. Spore in LM, equatorial view. 19. Osmunda parschlugiana, small pinna (IMNH 6) Plate 5.3 1–3. Ephedra sp. 1. Pollen grain in SEM, polar view. 2. Detail of pollen grain surface. 3. Pollen grain in LM, polar view. 4–6. Ephedra sp. 4. Pollen grain in SEM. 5. Detail of pollen grain surface. 6. Pollen grain in LM, equatorial view. 7–9. Cupressaceae gen. et spec. indet. 2 (Glyptostrobus sp.). 7. Pollen in SEM. 8. Detail of pollen grain surface. 9. Pollen grain in LM. 10 and 11. Cupressaceae gen. et spec. indet. 2 (Glyptostrobus sp.). 10. Pollen grain in SEM, detail of surface. 11. Pollen grain in LM. 12–14. Cupressaceae gen. et spec. indet. 2 (Glyptostrobus sp.). 12. Pollen grain in SEM. 13. Detail of pollen grain surface. 14. Pollen grain in LM Plate 5.4 1. Cryptomeria anglica, branched shoot with needle like leaves (S 093406). 2. Detail of Fig. 1 showing leaf arrangement. 3. Cryptomeria anglica, long shoot with shorter lateral shoots (IMNH 88-01). 4. Cryptomeria anglica, epidermis in LM, epidermal tissue with densely spaced and irregularly oriented stomata (S 093948-A). 5. Cryptomeria anglica, epidermis in LM, epidermal tissue with densely spaced and irregularly oriented stomata (S 093406). 6. Abies steenstrupiana, cone scale (S 094057-2). 7. Abies steenstrupiana, cone scale (IMNH 59). 8. Abies steenstrupiana, winged seed (S 094013-2). 9. Abies steenstrupiana, winged seed (S 094032-2). 10–12. Abies sp. 1. 10. Bisaccate pollen grain in SEM, oblique proximal polar view. 11. Detail of corpus. 12. Pollen grain in LM, polar view Plate 5.5 1–3. Pinus sp. 1. (Diploxylon type) 1. Bisaccate pollen grain in SEM, distal polar view. 2. Detail of pollen grain surface showing both saccus (lower right) and corpus (upper left). 3. Bisaccate pollen grain in LM, distal polar view. 4. Cathaya sp., numerous oblong needle-like leaves (IMNH 43). 5. Cathaya sp., epidermis in LM, epidermal tissue consisting of narrow and oblong cells, stomata in rows (IMNH 43). 6. Cathaya sp., epidermis in LM, epidermal tissue consisting of narrow and oblong cells (IMNH 43). 7. Cathaya sp., epidermis in LM, epidermal tissue with stomata in rows (IMNH 43). 8. Cathaya sp., epidermis in SEM, epidermal tissue consisting of narrow and oblong cells (IMNH 43). 9. Cathaya sp., epidermis in SEM, epidermal tissue with stomata (IMNH 43) Explanation of Plates 261 Plate 5.6 1. Picea sp., shoot with leaves (IMNH 175). 2. Picea sp., shoot with raised scars (IMNH 130). 3. Picea sect. Picea sp., female cone (IMNH org 6). 4. Picea sect. Picea sp., female cone (S094048). 5. Picea sect. Picea sp., female cone (S 094059). 6. Picea sp., winged seed (IMNH). 7. Picea sp., winged seed (S 094027-1). 8–10. Picea sp. 8. Bisaccate pollen in SEM, equatorial view. 9. Detail of cappa. 10. Pollen grain in LM, equatorial view Plate 5.7 1–3. Sciadopitys sp. 1. Pollen grain in SEM, proximal polar view. 2. Detail of pollen grain surface. 3. Pollen grain in LM, polar view. 4. Tsuga sp., long shoot with leaves (GM 673). 5. Tsuga sp., needle (S 094004-1). 6. Tsuga sp., needle (S 093406-2). 7. Tsuga sp., epidermis in LM, stomata in rows (S 094004-1). 8. Tsuga sp., epidermis in LM, consisting of long and narrow cells and stomata in rows (S 093406-2). 9–11. Tsuga sp. 1. Pollen grain in SEM, proximal polar view. 10. Detail of pollen grain surface. 11. Pollen grain in LM, polar view Plate 5.8 1–3. Ilex sp. 1. 1. Pollen grain in SEM, equatorial view. 2. Detail of pollen grain surface. 3. Pollen grain in LM, equatorial view. 4. Lonicera sp., narrow elliptic leaf, base acute (S 093936). 5. Lonicera sp., narrow elliptic leaf (IMNH). 6–8. Lonicera sp. 1. 6. Pollen grain in SEM. 7. Detail of pollen grain surface. 8. Pollen grain in LM. 9–11. Viburnum sp. 9. Pollen grain in LM, equatorial view. 10. Detail of pollen grain surface. 11. Pollen grain in LM, equatorial view. 12–14. Viburnum sp. 12. Pollen grain in SEM, polar view. 13. Detail of pollen grain surface. 14. Pollen grain in LM Plate 5.9 1. Alnus cecropiifolia, large wide elliptic leaf with round base (IMNH). 2. Alnus cecropiifolia, large wide elliptic leaf with acute apex (IMNH). 3. Alnus sp., male catkins (IMNH org 113-02). 4. Alnus cecropiifolia, detail showing round base (IMNH 6729). 5. Alnus sp., narrowwinged seed (IMNH 204). 6. Alnus kefersteinii, female infructescense (IMNH org 120-01). 7. Alnus gaudinii, large wide elliptic leaf (IMNH). 8. Alnus gaudinii, medium sized ovate leaf (IMNH 50). 9. Alnus gaudinii, large wide elliptic leaf with cordate base and a long petiole (S 087465). 10. Alnus gaudinii, medium sized narrow elliptic leaf (IMNH 194). 11–13. Alnus sp. 1. 11. Pollen grain in LM, polar view. 12. Pollen grain in SEM, polar view. 13. Detail of pollen grain surface Plate 5.10 1. Betula islandica, medium sized leaf (S 087422). 2. Detail of Fig. 1 showing venation and teeth in basal part. 3. Detail of Fig. 1 showing venation and teeth in apical part. 4. Betula islandica, wide elliptic leaf with cordate base (IMNH 94). 5. Betula islandica, large wide elliptic leaf with cordate base and acute apex (IMNH). 6. Betula islandica, large wide elliptic leaf with round base (IMNH 170-01). 7. Detail of Fig. 6 showing venation and teeth along margin. 8. Betula islandica, catkin scale with long lateral lobes (IMNH). 9. Betula islandica, two catkin scales with long and narrow lobes (S 093963). 10. Betula islandica, catkin scale (IMNH org 90). 11. Betula islandica, catkin scale (IMNH 88-02). 12–14. Betula sp. 12. Pollen grain in SEM, polar view. 13. Detail of pollen grain surface. 14. Pollen grain in LM, polar view Plate 5.11 1. Carpinus sp. MT1, large wide elliptic leaf with asymmetric base (IMNH 166). 2. Detail of Fig. 1 showing venation and teeth along margin. 3. Carpinus sp. MT2, large narrow elliptic leaf with serrate margin (IMNH). 4. Carpinus sp. MT2, small elliptic leaf with serrate margin (IMNH). 5. Carpinus sp., winged fruit, partly preserved (IMNH 67812-06). 6 and 8. Carpinus sp. 1. 6. Pollen grain in LM, polar view. 8. Pollen grain in SEM, polar view. 7, 9 and 10. Carpinus sp. 1. 7. Pollen grain in LM, polar view. 9. Pollen grain in SEM, polar view. 10. Detail of pollen grain surface. 11–13. Carpinus sp. 1. 11. Pollen grain in SEM, polar view. 12. Detail of pollen grain surface. 13. Pollen grain in M polar view Plate 5.12 1. Corylus sp., part of a large leaf (S 094065). 2. Detail of Fig. 1 showing tertiary venation and teeth along margin. 3. Detail of Fig. 1 showing veins entering teeth. 4–7. 262 5 The Classic Surtarbrandur Floras (12 Ma) Rhododendron sp. 2. 4. Tetrad in SEM. 5. Detail of tetrad surface showing viscin threads. 6. Tetrad in LM. 7. Detail of tetrad surface showing microverrucae. 8–11. Rhododendron sp. 1 (R. ponticum type). 8. Tetrad in SEM. 9. Tetrad in LM. 10. Detail of tetrad surface showing oblong microrugulae. 11. Detail of tetrad surface showing viscin thread Plate 5.13 1–3. Carya sp. 1. Pollen grain in SEM, polar view. 2. Detail of pollen grain surface. 3. Pollen grain in LM, polar view showing polar thinning. 4–6. Pterocarya sp. 4. Pollen grain in SEM, polar view. 5. Detail of pollen grain surface. 6. Pollen grain in LM, polar view. 7–9. Lemna sp. 7. Pollen grain in SEM. 8. Detail of pollen grain surface. 9. Pollen grain in LM. 10–12. Platanus sp. 10. Pollen grain in SEM, equatorial view. 11. Detail of pollen grain surface. 12. Pollen grain in LM, equatorial view Plate 5.14 1. Laurophyllum sp. (Laurus), narrow elliptic leaf (S 094035-01). 2. Laurophyllum sp. (Laurus), epidermis in LM, epidermal tissue with oil-cells (S 094035-01). 3. Sassafras ferrettianum, medium sized 3 lobed leaf (IMNH). 4. Sassafras ferrettianum, small elliptic leaf (IMNH 73-01). 5. Sassafras ferrettianum, large wide elliptic/suborbiculate leaf (IMNH). 6. Sassafras ferrettianum, large 3 lobed leaf (IMNH org 107) Plate 5.15 1. Liriodendron procaccinii, small 4 lobed leaf (GM 6790). 2. Liriodendron procaccinii, part of a large 4 lobed leaf (IMNH 4787). 3. Liriodendron procaccinii, samaroid fruit (S 094043-02). 4. Magnolia sp., small narrow elliptic leaf (S 094018). 5. Magnolia sp., medium sized narrow elliptic leaf with (IMNH 111-03). 6. Magnolia sp., large leaf with entire margin (IMNH 117-01). 7. Magnolia sp., seed (IMNH org 120-02). 8. Magnolia sp., epidermis in LM, epidermal tissue consisting of undulate cells (S 094068) Plate 5.16 1. Comptonia hesperia, medium sized lobed leaf (S 134428). 2. Detail of Fig. 1 showing lobes. 3. Comptonia hesperia, small lobed leaf (IMNH). 4. Comptonia hesperia, basal part of leaf (S 094066-02). 5. Detail of Fig. 4 showing venation into lobes. 6. cf. Fraxinus sp, samara (IMNH 54-02). 7. Cyperaceae gen. et spec. indet. A, fragment of leaf (IMNH 6745-06A). 8. Cyperaceae gen. et spec. indet. A, fragment of leaf (IMNH 6745-06B). 9. Phragmites sp. 10. Phragmites sp Plate 5.17 1. Rosaceae gen. et spec. indet. A, medium sized elliptic leaf (IMNH 66). 2. Rosaceae gen. et spec. indet. A, part of small leaf, (S 134378-01). 3. Detail of Fig. 2 showing venation and teeth along margin. 4. Rosaceae gen. et spec. indet. B, large elliptic leaf with cordate base (S 094044-01). 5. Rosaceae gen. et spec. indet. C, large elliptic leaf with obtuse base (S 093734). 6. Detail of Fig. 5 showing venation and teeth along margin. 7. Detail of Fig. 1 showing venation and teeth along margin. 8. Rosaceae, gen. et spec. indet. B (IMNH). 9. cf. Rosaceae, small fruit with the remnants of a calyx (S 134357) Plate 5.18 1–3. Rosaceae gen. et spec. indet. 3. 1. Pollen grain in SEM, equatorial view. 2. Detail of pollen grain surface. 3. Pollen grain in LM, equatorial view. 4–6. Rosaceae gen. et spec. indet. 3. 4. Pollen grain in SEM, equatorial view. 5. Detail of pollen grain surface. 6. Pollen grain in LM, equatorial view. 7–9. Sanguisorba sp. 7. Pollen grain in SEM, equatorial view. 8. Detail of pollen grain surface. 9. Pollen grain in LM, equatorial view. 10–12. Sanguisorba sp. 10. Pollen grain in SEM, equatorial view. 11. Detail of pollen grain surface. 12. Pollen grain in LM, equatorial view Plate 5.19 1. Populus sp. A (ex group P. tremula L.), large suborbiculate leaf with a long petiole (IMNH 6719-01). 2. Populus sp. A (ex group P. tremula L.), large suborbiculate leaf with a long petiole (S 134363). 3. Salix gruberi, narrow elliptic leaf (IMNH). 4. Salix gruberi, narrow elliptic leaf with petiole (S 134360). 5. Salix gruberi, elliptic leaf (S 134358). 6. Detail of Fig. 5 showing venation and teeth along margin. 7–10. Salix sp. 2. 7. Pollen grain in SEM, equatorial view. 8. Detail of pollen grain surface. 9. Detail of pollen grain surface. 10. Pollen grain in LM, equatorial view Explanation of Plates 263 Plate 5.20 1. Acer askelssonii, medium sized 3 lobed leaf (IMNH 176). 2. Acer askelssonii, large samara (IMNH org 106). 3. Acer crenatifolium subsp. islandicum, small 3 lobed leaf (IMNH). 4. Acer crenatifolium subsp. islandicum, small 3 (5) lobed leaf (IMNH). 5. Acer crenatifolium subsp. islandicum, samaras (IMNH). 6. Acer crenatifolium subsp. islandicum, samaras (IMNH 32). 7. Acer crenatifolium subsp. islandicum, samara (IMNH 91) Plate 5.21 1–3. Acer sp. 3. 1. Pollen grain in SEM, equatorial view. 2. Detail of pollen grain surface. 3. Pollen grain in LM, equatorial view. 4–6. Acer sp. 3. 4. Pollen grain in SEM, equatorial view. 5. Detail of pollen grain surface. 6. Pollen grain in LM, equatorial view. 7–9. Acer sp. 2. 7. Pollen grain in SEM, equatorial view. 8. Detail of pollen grain surface. 9. Pollen grain in LM, equatorial view Plate 5.22 1. Smilax sp., lower part of leaf (S 093953). 2. Detail of Fig. 1 showing venation. 3. Ulmus cf. pyramidalis, narrow elliptic leaf with forking secondary veins (IMNH). 4. Ulmus cf. pyramidalis, large elliptic leaf with forking secondary veins (S093964). 5. Ulmus cf. pyramidalis, small wide leaf (IMNH). 6. Ulmus cf. pyramidalis, small ovate leaf (IMNH). 7. Ulmus cf. pyramidalis, small ovate leaf (IMNH). 8–10. aff. Cedrelospermum sp. 8. Pollen grain in SEM. 9. Detail of pollen grain surface. 10. Pollen grain in LM Plate 5.23 1–3. Tetracentron atlanticum. 1. Pollen grain in SEM, equatorial view. 2. Detail of pollen grain surface. 3. Pollen grain in LM, equatorial view. 4–6. Tetracentron atlanticum. Pollen gain in SEM, equatorial view. 5. Detail of pollen grain surface. 6. Pollen grain in LM, equatorial view. 7–9. Tetracentron atlanticum. 7. Pollen grain in SEM, oblique view. 8. Detail of pollen grain surface. 9. Pollen grain in LM, oblique view. 10–12. Tetracentron atlanticum. 10. Pollen grain in SEM, oblique polar view. 11. Detail of pollen grain surface. 12. Pollen grain in LM, oblique polar view. 13–15. Valerianaceae gen. et spec. indet. 13. Pollen grain in SEM, Equatorial view. 14. Detail of pollen grain surface. 15. Pollen grain in LM, equatorial view Plate 5.24 1. aff. Calycanthaceae, large leaf with obtuse base (IMNH 98-01). 2. aff. Calycanthaceae, small elliptic leaf (IMNH 64-03). 3. aff. Calycanthaceae, small elliptic leaf with acute base (S 093977). 4. Dicotylophyllum sp. A, leaf fragment (S 094061) Plate 5.25 1–3. Pollen type 1. 1. Pollen grain in SEM, equatorial view. 2. Detail of pollen grain surface. 3. Pollen grain in LM, equatorial view. 4–6. Pollen type 1. 4. Pollen grain in SEM, equatorial view. 5. Detail of pollen grain surface. 6. Pollen grain in LM, equatorial view. 7–9. Pollen type 2. 7. Pollen grain in SEM, equatorial view. 8. Detail of pollen grain surface. 9. Pollen grain in LM, equatorial view. 10–12. Pollen type 2. 10. Pollen grain in SEM, equatorial view. 11. Detail of pollen grain surface. 12. Pollen grain in LM, equatorial view Plate 5.26 1–3. Pollen type 3. 1. Pollen grain in SEM, equatorial view. 2. Detail of pollen grain surface. 3. Pollen grain in LM, equatorial view. 4–6. Pollen type 4. 4. Pollen grain in SEM. 5. Detail of pollen surface. 6. Pollen grain in LM. 7–9. Pollen type 5. 7. Pollen grain in SEM. 8. Detail of pollen grain surface. 9. Pollen grain in LM. 10–12. Pollen type 6. 10. Pollen grain in SEM. 11. Detail of pollen grain surface. 12. Pollen grain in LM Plate 5.27 1–3. Pollen type 7. 1. Pollen grain in SEM. 2. Detail of pollen grain surface. 3. Pollen grain in LM. 4–6. aff. Calycanthaceae 4. Pollen grain in SEM, equatorial view. 5. Detail of pollen grain surface. 6. Pollen grain in LM, equatorial view. 7–9. aff. Calycanthaceae 7. Pollen grain in SEM, equatorial view. 8. Detail of pollen grain surface. 9. Pollen grain in LM, equatorial view. 10–12. aff. Calycanthaceae 10. Pollen grain in SEM, equatorial view. 11. Detail of pollen grain surface. 12. Pollen grain in LM, equatorial view 264 5 The Classic Surtarbrandur Floras (12 Ma) Plates Plate 5.1 Plates 265 Plate 5.2 266 5 The Classic Surtarbrandur Floras (12 Ma) Plate 5.3 Plates 267 Plate 5.4 268 5 The Classic Surtarbrandur Floras (12 Ma) Plate 5.5 Plates 269 Plate 5.6 270 5 The Classic Surtarbrandur Floras (12 Ma) Plate 5.7 Plates 271 Plate 5.8 272 5 The Classic Surtarbrandur Floras (12 Ma) Plate 5.9 Plates 273 Plate 5.10 274 5 The Classic Surtarbrandur Floras (12 Ma) Plate 5.11 Plates 275 Plate 5.12 276 5 The Classic Surtarbrandur Floras (12 Ma) Plate 5.13 Plates 277 Plate 5.14 278 5 The Classic Surtarbrandur Floras (12 Ma) Plate 5.15 Plates 279 Plate 5.16 280 5 The Classic Surtarbrandur Floras (12 Ma) Plate 5.17 Plates 281 Plate 5.18 282 5 The Classic Surtarbrandur Floras (12 Ma) Plate 5.19 Plates 283 Plate 5.20 284 5 The Classic Surtarbrandur Floras (12 Ma) Plate 5.21 Plates 285 Plate 5.22 286 5 The Classic Surtarbrandur Floras (12 Ma) Plate 5.23 Plates 287 Plate 5.24 288 5 The Classic Surtarbrandur Floras (12 Ma) Plate 5.25 Plates 289 Plate 5.26 290 5 The Classic Surtarbrandur Floras (12 Ma) Plate 5.27