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地层、古生物和群落古生态资料记录了一次发生在奥陶-志留纪之交、“江-绍断裂带”西北侧(浙西、浙西北和赣东北隅)海域生物相、沉积相和古地理格局的重大变化.晚奥陶世凯迪晚期研究南区西缘为“怀玉山地”(新名),东南缘为浙赣海;在长坞组沉积早期,从“怀玉山地”向东北方海水加深,已知最深水域在江山-龙游-兰溪一带,海域呈现西南浅、北东深的格局;长坞组沉积中晚期,海底快速抬升,原先的深水域显著变浅甚至海水退出,海面下跌略早于奥陶纪末全球范围的海面下降事件.到赫南特期和志留纪初鲁丹早期,由于“华夏古陆”从东南方进入且快速扩大,本区变成了浅水海湾并滋生了华夏正形贝动物群.海面的大幅度下降、生物群面貌和性质的剧烈变化以及浅水底栖壳相生物的大批迁入,均发生在奥陶-志留纪交界期内,这是与特殊而强烈的区域地质构造活动密不可分的.它暗示了当时“扬子”与“华夏”两个地块的构造演化和汇聚拼合过程,并造成了“华夏古陆”随后向西北扩展的强大态势.
Stratigraphy, palaeontology and community paleoecology data record the biological facies occurring in the Ordovician-Silurian junction, the northwestern side of “Jiang-Shao fault zone” (west Zhejiang, northwestern Zhejiang and northeastern Jiangxi), sedimentary facies And the paleogeographic pattern.North of the Late Ordovician Kaidi Study was “Huaiyu Mountain” (new name) in the Late Southern Research Area of the Late Ordovician and Zhejiang-Jiangxi Sea in the southeastern margin. In the early sedimentation of the Changwu Formation, Yushan land “deepened to the northeast of the sea, the deepest known waters in the Jiangshan - Longyou - Lanxi area, the sea area showed a southwest shallow, north-east pattern; late dock group deposition late, seafloor rapid rise, the original deep-water area significantly Shallowing and even seawater withdrawal, the sea surface dropped slightly earlier than the worldwide decline of the sea surface at the end of the Ordovician period.From the beginning of Lunan period and the early Silurian of Lutheran in early Ludan, as the ”Huaxia ancient land“ entered and expanded rapidly from the southeast , This area has become a shallow water bay and breed Cathaysia terrestris fauna.The drastic decline of the sea surface, the dramatic changes in the appearance and nature of the biota, and the massive migration of shallow-benthic marine benthic fauna all occur in the Ordovician- During the Silurian boundary, this was closely related to the special and intense regional geological tectonics Divisible. It implies that time ”Yangzi “ and ”China “ tectonic evolution and convergence of the two plots split process, and create a ”Cathaysia " then expanded to the northwest powerful trend.