Paleobiogeographical study on the Permian brachiopods of the Akiyoshi Terrane

1994年，对收集到的大量上石炭统秋吉灰岩腕足动物标本和下二叠统太白灰岩标本进行了研究。通过详细的野外调查，收集了二叠系Tsunemori组腕足动物。为了比较阿曼二叠纪腕足动物的区系特征，对其进行了研究和描述。1995年报道了两种早晚石炭世腕足动物Weiningia，并讨论了它们的古地理意义。对分布在秋吉西部邻区三叠纪矿群中的一种Lingula进行了判别和讨论。三叠纪Lingula对于考虑二叠纪末期发生的最大规模海洋无脊椎动物灭绝的过程具有重要意义。本文讨论了中二叠世恒森组腕足动物。初步研究结果表明：Tsunemori腕足动物区系与中国南方扬子地台中二叠世晚期至晚二叠世早期的腕足动物区系密切相关。Tsunemori腕足动物群的特征是特提斯温暖水域和高纬度地区冷水地区的混合。这说明海山上的明吉生物礁群可能在中二叠世末或晚二叠世初在扬子地台北缘地区发生了崩塌。这些初步结果已于1995年在加拿大萨德伯里劳伦森大学举行的第三届国际腕足动物大会上发表和宣读。为了弄清日本西南部上古生界的地质历史，将尽快对收集到的秋吉石灰岩群石炭系腕足动物和恒森组二叠纪腕足动物进行描述。

In 1994 a huge number of collected materials on the Upper Carboniferous brachiopods from the Akiyoshi Limestone as well as the Lower Permian specimens from the Taishaku Limestone were examined. Permian brachiopods from the Tsunemori Formation have been collected with the detailed field survey. For the purpose of comparing the faunal character, Permian brachiopod faunas from Oman have been examined and described.In 1995 two species of early Late Carboniferous brachiopod Weiningia have been described and their paleobiogeographical significance was also discussed. A Lingula species was discriminated and discussed from the Triassic Mine Group, distiributed in the western neighboring region of Akiyoshi. The Triassic Lingula is very significant to consider the process of the largest mass extinction occured within marine invertebrates at the end of the Permian. The Middle Permian brachiopod from the Tsunemori Formation have been discussed. The preliminary research of them has been concluded as follows : The Tsunemori brachiopod fauna is closely related with that of the late Middle to early Late Permian of the Yangtze Platform in southern China. Elements of the Tsunemori brachiopod fauna are characterized by mixture of those in the warm water region of Tethys as well as the cool water in the high latitudal regions. This means that the Akiyoshi organic reef complex on a seamount probably collapsed the northern marginal region of the Yangtze Platform at the end of the Middle Permian or the begining of the Late Permian.These preliminary results have been presented and read in the 3rd International Brachiopod Congress held at the Laurentian University, Sudbury, Canada in 1995. The collected Carboniferous brachiopods from the Akiyoshi Limestone Group and the Permian brachiopods from the Tsunemori Formation will be described as soon as possible for the purpose of making clear the geologic history of the Upper Paleozoic of South west Japan.