Lower Cretaceous (Upper Barremian-Lower Aptian?) Palynoflora from the Kitadani Formation (Tetori Group, Inner Zone of Central Japan)
Lower Cretaceous (Upper Barremian-Lower Aptian?) Palynoflora from the Kitadani Formation (Tetori Group, Inner Zone of Central Japan)
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DOI：
10.2517/1342-8144-17.3.201
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发表时间：
2013-08
期刊：
影响因子：
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通讯作者：
J. Legrand;D. Pons;K. Terada;Atsushi Yabe;H. Nishida
中科院分区：
文献类型：
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作者：
J. Legrand;D. Pons;K. Terada;Atsushi Yabe;H. Nishida
摘要：在日本中部内带出露的手取群，因其丰富的植物群和脊椎动物化石组合而得到了广泛研究。作者首次对北谷组的孢粉植物群进行了研究，根据其中所记录的淡水双壳类，其时代被确定为巴列姆晚期至阿普特早期。所研究的组合产出了45属41种孢子和裸子植物花粉粒、一些淡水藻类、一种叶表真菌以及各种植物碎片。未观察到被子植物花粉粒。这里详细描述的一些类型在文献中尚未有记载。它们可能属于新种，但标本的稀缺性使我们暂时将它们置于未定名状态。这项孢粉学研究为目前关于东亚巴列姆 - 阿普特期手取型古植物群的知识增添了新数据。作者将孢粉清单与最近发表的从日本西南部外带铫子群巴列姆期地层获得的数据进行了比较。然后，他们将研究结果置于先前对田谷植物群的古环境重建之中，并证实了一种温暖温带且适度湿润的气候，局部地区较为干燥。即使组合中的一些成分表明存在搬运作用，但它们都源自大陆，证实了沉积环境为河湖环境。
Abstract The Tetori Group, which crops out in the Inner Zone of central Japan, has been extensively studied for its rich floral and vertebrate fossil assemblages. The authors provide the first contribution to the palynoflora of the Kitadani Formation, which has been dated as late Barremian to early Aptian on the basis of the freshwater bivalves recorded from it. The studied assemblage yields 45 genera and 41 species of spores and gymnosperm pollen grains, some freshwater algae, one epiphyllous fungus, and various plant fragments. No angiosperm pollen grains were observed. Some forms described here in detail are not yet known from the literature. They probably correspond to new species, but the scarcity of the specimens has caused us to place them temporarily in open nomenclature. This palynological study adds new data to the present knowledge on the Barremian-Aptian Tetori-type Paleoflora of eastern Asia. The authors compare the palynological inventory with recently published data obtained from the Barremian strata of the Choshi Group, the Outer Zone of Southwest Japan. Then, they situate the results among the previous paleoenvironmental reconstructions of the Tamodani Flora, and confirm a warm temperate and moderately humid climate, with locally drier conditions. Even if some elements of the assemblage suggest transportation, all of them are of continental origin and confirm a fluvio-lacustrine environment for the deposition.