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Larry E. Davis - One of the best experts on this subject based on the ideXlab platform.
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A morphotype catalog and paleoenvironmental interpretations of Early Miocene fossil leaves from the Hiwegi Formation, Rusinga Island, Lake Victoria, Kenya
Palaeontologia electronica, 2013Co-Authors: Daniel P. Maxbauer, Daniel J. Peppe, Marion K. Bamford, Kieran P. Mcnulty, William E.h. Harcourt-smith, Larry E. DavisAbstract:Early Miocene deposits on Rusinga Island (Lake Victoria, Kenya) contain an abundance of faunal and floral remains. Despite the attention that has historically been given to the Early Miocene fauna from Rusinga Island, little attention has been given to the Early Miocene fossil floras and to date no studies have described fossil leaf morphotypes from Rusinga Island. Here, we present a morphotype catalog of fossil leaves collected from the Grit Member of the Hiwegi Formation on Rusinga Island. We describe 14 morphotypes, comprised of 12 dicotyledonous angiosperms and two monocotyledonous angiosperms, as well as two distinct dicotyledonous angiosperm leaf fragments. Characteristics of the flora and sedimentological evidence, coupled with previous research, suggest that the local paleoenvironment was a riparian habitat within a patchwork of woodland and forested biomes in what was likely a warm climate. This work represents an important first step in understanding the Early Miocene vegetation of Rusinga Island, and highlights both the need and potential for future research on these Early Miocene floras.
Suzanne J. Hand - One of the best experts on this subject based on the ideXlab platform.
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Evidence for a giant parrot from the Early Miocene of New Zealand.
Biology letters, 2019Co-Authors: Trevor H. Worthy, Suzanne J. Hand, Michael Archer, R. Paul Scofield, Vanesa L. De PietriAbstract:Insular avifaunas have repeatedly spawned evolutionary novelties in the form of unusually large, often flightless species. We report fossils from the Early Miocene St Bathans Fauna of New Zealand t...
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A NEW HIPPOSIDERID GENUS (MICROCHIROPTERA) FROM AN Early Miocene BAT COMMUNITY IN AUSTRALIA
Palaeontology, 2005Co-Authors: Suzanne J. Hand, Michael ArcherAbstract:A new genus and species of hipposiderid bat is described from an Early Miocene cave deposit (Bitesanten- nary Site) in the Riversleigh World Heritage fossil property, northern Australia. Eight hipposiderid genera are now recor- ded from Riversleigh's Miocene sediments: Hipposideros, Brachipposideros, Rhinonycteris, Riversleigha, Xenorhinos, Miophyllorhina, Archerops and Brevipalatus gen. nov. The new taxon appears to be most closely related to Australian endemic Rhinonycteris and Brachipposideros species, but its autapomorphically very short palate distinguishes it from other members of this relatively plesiomorphic group. It is one of eight hipposiderid species recovered from the Bitesan- tennary Site deposit, and one of 11 recorded from River- sleigh's Early Miocene sediments. Compared with modern bat faunas, the Early Miocene Riversleigh bat community differs strikingly in its high hipposiderid diversity but may differ less in its overall trophic structure.
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Oldest Australian vespertilionid (Microchiroptera) from the Early Miocene of Riversleigh, Queensland
Alcheringa: An Australasian Journal of Palaeontology, 2002Co-Authors: Henri Menu, Suzanne J. Hand, Bernard SigéAbstract:An upper molar of a small bat, here described from an Early Miocene freshwater lime-stone deposit at Riversleigh, northwestern Queensland, is the oldest record in Australia of the microchiropteran family Vespertilionidae. The new taxon is referred to the cosmopolitan genus Leuconoe, but it does not appear to be closely related to the two extant Australian species of this genus.
Wu Zhenhan - One of the best experts on this subject based on the ideXlab platform.
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Tectonics and Topography of the Tibetan Plateau in Early Miocene
Acta Geologica Sinica - English Edition, 2014Co-Authors: Wu Zhenhan, Yan Yang, Patrick J. Barosh, Wu Zhonghai, Yaoling ZhangAbstract:: Early Miocene stratigraphy, major structural systems, magmatic emplacement, volcanic eruption, vegetation change and paleo-elevation were analyzed for the Tibetan Plateau after regional geological mapping at a scale of 1:250,000 and related researches, revealing much more information for tectonic evolution and topographic change of the high plateau caused by Indian-Asian continental collision. Lacustrine deposits of dolostone, dolomite limestone, limestone, marl, sandstone and conglomerate of weak deformation formed extensively in the central Tibetan Plateau, indicating that vast lake complexes as large as 100,000–120,000 km2 existed in the central plateau during Early Miocene. Sporopollen assemblages contained in the lacustrine strata indicate the disappearance of most tropical-subtropical broad-leaved trees since Early Miocene and the flourishing of dark needle-leaved trees during Early Miocene. Such vegetation changes adjusted for latitude and global climate variations demonstrate that the central Tibetan Plateau rose to ca. 4,000–4,500 m and the northeastern plateau uplifted to ca. 3,500–4,000 m before the Early Miocene. Intensive thrust and crustal thickening occurred in the areas surrounding central Tibetan Plateau in Early Miocene, formed Gangdise Thrust System (GTS) in the southern Lhasa block, Zedong-Renbu Thrust (ZRT) in the northern Himalaya block, Main Central Thrust (MCT) and Main Boundary Thrust (MBT) in the southern Himalaya block, and regional thrust systems in the Qaidam, Qilian, West Kunlun and Songpan-Ganzi blocks. Foreland basins formed in Early Miocene along major thrust systems, e.g. the Siwalik basin along MCT, Yalung-Zangbu Basin along GTS and ZRT, southwestern Tarim depression along West Kunlun Thrust, and large foreland basins along major thrust systems in the northeastern margin of the plateau. Intensive volcanic eruptions formed in the Qiangtang, Hoh-Xil and Kunlun blocks, porphyry granites and volcanic eruptions formed in the Nainqentanglha and Gangdise Mts., and leucogranites and granites formed in the Himalaya and Longmenshan Mts. in Early Miocene. The K2O weight percentages of Early Miocene magmatic rocks in the Gangdise and Himlayan Mts. are found to increase with distance from the MBT, indicating the genetic relationship between regional magmatism and subduction of Indian continental plate in Early Miocene.
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Vast Early Miocene lakes of the central Tibetan Plateau
Geological Society of America Bulletin, 2008Co-Authors: Wu Zhenhan, Patrick J. Barosh, Wu Zhonghai, Hu Daogong, Zhao Xun, Ye PeishengAbstract:Lacustrine strata of the Wudaoliang Group demonstrate that two vast lake complexes covered the central Tibetan Plateau during Early Miocene time. The Wudaoliang Group, which is characterized by dolostone, limestone, and marl as thick as 310–350 m, lies horizontally or with a slight dip above Oligocene reddish-brown sandstone, and is covered by upper Miocene and Pliocene mudstone and sandstone. The extensive distribution of this group outlines interconnected lake basins of 5000–15,000 km 2 or larger in the north-central Tibetan Plateau, such as the Wudaoliang, Beiluhe, Tuotuohe, Tongtianhe, and East Wenquan Basins, and lake basins 2000 km 2 or larger in the south-central plateau, such as the Ando, Naqu, Bangoin, Lunpola, and Shuanghu Basins. These lake basins, separated by mountain ranges and islands, were linked by water passages in Early Miocene time, when they apparently formed a huge lake complex that covered as much as 100,000 km 2 in the north-central Tibetan Plateau and another one >50,000 km 2 in the south-central part of the plateau. Such immense lakes existed for several million years between ca. 23.5 and ca 13.5 Ma after the Tibetan Plateau rose, and their interconnected basins define the topography during Early Miocene time. The fossils contained in these basins indicate a change from the warm, dry climate of the Oligocene to moderately cool and wet conditions at the beginning of the Early Miocene, followed by progressive cooling and drying, which suggests continuous uplift during deposition of the Wudaoliang Group.
Daniel P. Maxbauer - One of the best experts on this subject based on the ideXlab platform.
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A morphotype catalog and paleoenvironmental interpretations of Early Miocene fossil leaves from the Hiwegi Formation, Rusinga Island, Lake Victoria, Kenya
Palaeontologia electronica, 2013Co-Authors: Daniel P. Maxbauer, Daniel J. Peppe, Marion K. Bamford, Kieran P. Mcnulty, William E.h. Harcourt-smith, Larry E. DavisAbstract:Early Miocene deposits on Rusinga Island (Lake Victoria, Kenya) contain an abundance of faunal and floral remains. Despite the attention that has historically been given to the Early Miocene fauna from Rusinga Island, little attention has been given to the Early Miocene fossil floras and to date no studies have described fossil leaf morphotypes from Rusinga Island. Here, we present a morphotype catalog of fossil leaves collected from the Grit Member of the Hiwegi Formation on Rusinga Island. We describe 14 morphotypes, comprised of 12 dicotyledonous angiosperms and two monocotyledonous angiosperms, as well as two distinct dicotyledonous angiosperm leaf fragments. Characteristics of the flora and sedimentological evidence, coupled with previous research, suggest that the local paleoenvironment was a riparian habitat within a patchwork of woodland and forested biomes in what was likely a warm climate. This work represents an important first step in understanding the Early Miocene vegetation of Rusinga Island, and highlights both the need and potential for future research on these Early Miocene floras.
Chenglin Liu - One of the best experts on this subject based on the ideXlab platform.
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Early Miocene expansion of C4 vegetation on the northern Tibetan Plateau
Global and Planetary Change, 2019Co-Authors: Guoqing Xia, Michael Wagreich, Juan Pedro Rodríguez-lópez, Xiaoming Sun, Chenglin LiuAbstract:Abstract The proliferation of C4 photosynthesis in land plants marks the most important ecological shift in tropical and subtropical terrestrial ecosystems during the Cenozoic. Despite the wealth of geochemical data indicating an increased C4 biomass in the paleovegetation since the Late Miocene spatial and temporal variations of C4 plants abundance are not well known. The driving force for their expansion such as CO2 starvation, aridification and fire frequency are controversially discussed. Here we present an integrated review of the stable isotope stratigraphy, trace elements, palynology, lithological and phytolith record from Early-middle Miocene lacustrine sediments in the Hoh Xil Basin. We report the first known silicified wood fossils from the genus Picea and indicate the Hoh Xil region might have already reached an elevation above 2500 m at least in the Early Miocene, representing the Early uplift stage of northern Tibetan Plateau. Our results show that the expansion of C4 vegetation and the appearance of Picea in the interior of the Tibet during the Early Miocene may be related to Early uplift of the northern Tibetan Plateau and the consequent cooling event, PCO2 decrease, and aridification. We suggest that the C4 signal in vertebrate faunas predating the Early Miocene is due to the ecology of the herbivores (who preferred plants with C3 metabolism) rather than the lack of C4 plants in the vegetation.
