Early Albian palynoflora of ODP Hole 120-750B

A well-preserved, diverse sporomorph flora of over 60 species has been found in Cores 120-750B-12W through -14R from the Southern Kerguelen Plateau. Analysis of the flora indicates that the terrestrial sediments overlaying the basaltic basement are late Early Cretaceous in age. Ranges of the sporomorphs in other parts of Gondwana and the morphology and paucity of angiosperm pollen grains confine the age of this section to the early to possibly early middle Albian. The Albian palynomorph assemblages in Hole 750B are composed primarily of fern spores and podocarpaceous pollen, and show most similarity to those from southern Australia. Changes in the flora through time reflect the successional vegetation changes on barren volcanic islands, beginning with high percentages of colonizing ferns and maturing into conifer (podocarp) forests. The flora shows some signs of endemism, which may be a result of the isolated position of the Kerguelen Islands during the Early Cretaceous. This endemism is expressed by high percentages of a distinctive monosulcate pollen species Ashmoripollis woodywisei n.sp. of pteridosperm or cycadophytean origin, and by a thick-walled, monosulcate angiosperm pollen species of the genus Clavatipollenites. The climatic conditions were probably cool to temperate (mean annual temperature approximately 7°-12°C) and humid (annual rainfall >1000 mm), analogous to modern Podocarpus-dominated forests in New Zealand and in South American mountain regions.

Sporomorphs and dinoflagellate cysts of ODP Leg 113 holes

Palynological studies were carried out on Paleogene sections from Sites 693 and 696 of Ocean Drilling Project Leg 113 in the Weddell Sea region. Dinoflagellate cysts and sporomorphs were recovered at Site 696 (61°S, 42°W) indicating a middle Eocene to late Eocene/earliest Oligocene age for a glauconitic silt/sandstone. At Site 693 (70°S, 14°W) early Oligocene siliciclastic mud contains a low diversity palynoflora. In an upper Oligocene section (Site 693) only rare, reworked Mesozoic palynomorphs were encountered. Palynological data from Kerogen analyses, dinocysts, and sporomorphs are used to reconstruct the climatic change on the South Orkney microcontinent from the middle Eocene to the late Eocene/earliest Oligocene at Site 696 and the late early Oligocene/early late Oligocene time interval at Site 693 near the continental margin. The middle Eocene was a warm period in the Orkney region with good growing conditions for a warm temperate Nothofagus/conifer forest with an admixture of Proteaceae. Temperate surface water masses, which allowed the growth of a reasonably diverse dinocyst assemblage (ca. 15-20 species), persisted until the end of the Eocene at Site 696. Late early Oligocene sediments of Site 693 (Antarctic continental margin) contain only a low diversity dinocyst flora (two species). The major Cenozoic cooling event in the Weddell Sea region probably occurred at the Eocene/Oligocene boundary. A second dramatic climatic deterioration seems to have taken place during the late early/early late Oligocene, when dinocysts disappeared at the Dronning Maud Land margin area.

Palynomorph concentrations in ODP Hole 105-645B samples (Table 1)

Significant changes in terrestrial and marine environments of Baffin Bay occurred throughout the late Pliocene to Holocene. Upper Pliocene and lowermost Pleistocene sediments contain abundant pollen and spores, which indicates the existence of open, coniferous, boreal forest to forest tundra in areas surrounding Baffin Bay. The late Pliocene-earliest Pleistocene also is characterized by relatively rich, dinoflagellate cyst and acritarch assemblages of boreal character, in which the dominance of Cymatiosphaera and Peridiniaceae may indicate neritic influx of sediments. In contrast, the late-early Pleistocene to Holocene interval is marked by a sparse terrestrial and marine palynoflora, with rare productive intervals. The general paucity of the Pleistocene palynoflora suggests low primary productivity, both on land and offshore, probably caused by cold, dry, high arctic conditions.

Neogene palaeoclimate reconstructions in Anatolia (Turkey)

Neogene basins are widespread in Turkey and contain important lignite deposits. In this study, we reconstruct quantitatively the Late Oligocene-Miocene climate evolution in western and central Anatolia by applying the Coexistence Approach to the palynoflora. The obtained results are compared with the data derived from the published and ongoing studies in western and central Anatolia palynofloras by application of the Coexistence Approach. The Coexistence Approach results show that the sedimentation mainly developed on terrestrial environment under the warm subtropical climatic conditions and marine influence during the Chattian and Aquitanian period in western Anatolia (16.5-21.3°C of mean annual temperature (MAT) and 5.5-13.3°C of mean temperature of coldest month (CMT)). After the regression of the sea during the Burdigalian period, the vegetation developed under the terrestrial conditions, which had started in the Burdigalian time in western and central Anatolia and continued in the early-middle Serravallian period. Warm subtropical climate is suggested during the Chattian and Aquitanian period in western Anatolia and becomes cooler in subtropical conditions because of decreasing of the P/A-ratio during the latest Burdigalian-Langhian. The climate was subtropical in western and central Anatolia during the Early-Late Serravalian due to the increasing of the subtropical elements (17.2 to 20.8°C of MAT and 9.6 to13.1°C of CMT). Besides, decreasing of the CMT and MAT values in western and central Anatolia supports the latest Chattian-earliest Aquitanian warming and middle Miocene climatic optimum that is also globally observed. Warm temperate climatic conditions are observed in the Late Miocene. During the early-middle Tortonian, the values are 15.6 to 20.8°C for the MAT, 5.5 to 13.3°C for the CMT and 823 and 1520 mm for the mean annual precipitation (MAP). They had also dry seasons due to lower boundary of MAP lying at 823mm during the middle-Late Tortonian. The palaeotopography of central Anatolia was higher when compared to that of western Anatolia because dominance of the mountain forests was present during the Middle-Late Miocene in central Anatolia. This study provides the first quantitative model for Late Oligocene-Miocene palaeoclimatic evolution in western and central Anatolia.

(Figure 1) Stratigraphic distribution of taxa at DSDP Hole 79-547B

Twenty-five samples from selected cored intervals of problematic Triassic-Jurassic age from Sites 545, 546, and Hole 547B have been analyzed palynologically to aid age determination. Section 545-73-1 yielded a marine palynoflora of Sinemurian-Bajocian age. A palynoflora of nonmarine origin and assigned a Rhaetian-Hettangian age was recovered from halite in Section 546-18-2. Marine palynofloras of Hettangian-early Pliensbachian age were recovered from Sample 547B-24-CC to Section 547B-14-2. Sections 547B-28-1 to 547B-25-3 yielded impoverished nonmarine palynofloras to which only a general Rhaetian-Hettangian age could be given.

Table 2. Percentage of palynomorphs found in each sample through Longling section

The Longling Coal Mine (W. Yunnan) is situated in an area of substantial geotectonic activity. Its Late Pliocene palynoflora is of considerable interest, since the area represents a centre of biodiversity. Eighty-two palynomorphs belonging to 61 families were recovered from the lignite. The palynoflora is dominated by angiosperms (68.3%), with ferns (24.4%), gymnosperms (4.9%) and algae (2.4%). Comparisons indicate that most of the palynoflora was derived from the Montane Humid Evergreen Broad-leaved Forest, with lesser contributions from the Tsuga dumosa Forest and Evergreen Coniferous Broad-leaved Mixed Forest, as well as the Montane Mossy Evergreen Broad-leaved Forest. This indicates that the Late Pliocene climate was cooler than that of the present. In the course of the accumulation of the lignite, the climate underwent five major phases of warming and cooling.

(Table 2) Paleoclimate reconstruction for palynology samples of Turkey

Palynofloras of the Kocaçay and Cumaovasi basins in western Turkey that belong to a time-span from the late Early to late Middle Miocene (the late Burdigalian-Serravallian) are studied and compared with published palynofloras of Europe and Turkey. Palynological data and numerical climatic results obtained by the coexistence approach indicate palaeoclimate changed from warm subtropical to temperate during the late Burdigalian-Serravallian. Moreover, the palaeoclimates of the Kocacay and Cumaovasi basins are compared with continental palaeoclimatic records of coal-bearing sediments in western Turkey and current temperatures in the Izmir region. According to this comparison, palaeoclimatic results of these basins and other localities in western Turkey show a distinct difference as a result of orographic change. The palaeovegetation in the Kocaçay and Cumaovasi basins during the studied time-span was affected by palaeotopography and palaeoclimate. In these basins mixed mesophytic, coniferous forests, and swamp palaeovegetation generally predominated during the late Early-early Middle Miocene. The role of the herbaceous taxa increased at the end of the late Middle Miocene (the Serravallian) in the Kocaçay and Cumaovasi basins. It is obvious from the palynomorph data of these basins that grassland palaeovegetation started to expand in the late Middle Miocene. Unlike in Central Europe, where late Burdigalian and Langhian represent a period of outstanding warmth, the so-called Mid-Miocene Climatic Optimum, cold month mean temperatures reconstructed in this study point to an ongoing cooling trend, already from the late Burdigalian onwards, possibly related to increasing terrestrial conditions in the study area.