Pachycladina的生态环境及古地理意义

PALAEOECOLOGICAL ENVIRONMENT AND PALAEOGEOGRAPHICAL SIGNIFICANCE OF PACHYCLADINA(CONODONTA)

本文通过对宜兴张渚上青龙组Pachycladina与核形石关系的研究,指出这类牙形动物主要生活在潮下带浅滩藻坪相环境。同时,根据pachycladina及共生分子Paraehirognathus,Lonchodina,Neohindeodella的刺体变化和分布状况,对苏南地区早三叠世晚青龙期进行了古地理分区;苏州—宜兴一带为浅水区或浅滩,南京—靖江一带为深水区。

While studying conodonts from the Lower Triassic Chinglung Limestone in South Jiangsu, the present writer has found that the occurrence of Pachycladina is closely associated with oncoid limestonet:it is abundantly found in limestones with oncoids but absent or rare in limestones without oncoids. This indicates that Pachycladina and oncoids might share the same palaeoenvironment, characterized by low agitation and rich blue-green algae. Based upon the morphology and distribution of conodonts, a palaeogeographical map has been worked out with a shallow or shoal area in the Suzhou—Yixing district in the east and a deep water region in the Nanjing—Jingjiang district in the west.