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依据湖北恩施太阳河灯草坪奥陶系—志留系剖面的生物地层学和岩石学的研究,该剖面的沉积间断发生在Paraorthograptus pacificus带至Coronograptus cyphus带之间,共缺失5个笔石带。奥陶系、志留系之间黏土岩矿物分析显示,在奥陶系、志留系之间出现有高岭土,推断在其间可能上升为陆地。具体演变过程为:在晚奥陶世晚期P.pacificus带之前,该区属于黑色笔石页岩沉积环境;在P.pacificus带(也可能略早),该区抬升,形成水下高地,其沉积环境达到了水下风化面,出现了生物扰动现象,并伴有一定的水下动力作用;至奥陶纪最晚期—志留纪早期,该区进一步抬升,可能上升为陆地;至志留纪早期C.cyphus带,该区快速下降,恢复到黑色笔石页岩沉积环境。凯迪晚期的全球海平面下降和志留纪早期“华夏古陆”不断向西及西北扩展的耦合作用是导致该区上升为陆地的主要因素。对整个扬子地区奥陶纪-志留纪之交沉积间断的综合分析需要在多个剖面开展进一步的研究工作。
Based on the bio-stratigraphy and petrology of the Ordovician-Silurian section of the solar river lawn in Enshi, Hubei, the sedimentary discontinuity occurred between the Paraorthograptus pacificus belt and the Coronograptus cyphus belt, and a total of five pen-stone belts were missing. Analysis of clay rocks between the Ordovician and Silurian shows that there is kaolin between Ordovician and Silurian, suggesting that it may rise to land during this period. The evolutionary process is as follows: the area belongs to the black penolith shale depositional environment before the late Ordovician P.pacificus zone; in the P. pacificus zone (which may also be slightly earlier), the area rises to form an underwater highland The sedimentary environment has reached the underwater weathered surface, and the phenomenon of bioturbation has been observed, accompanied by a certain degree of submarine dynamic force. In the early Ordovician-Early Silurian, the area was further uplifted and may rise to land; In the early C. genphus zone, the area rapidly declines, recovering to a black pen-stone shale sedimentary environment. Late Kaidi global sea level decline and the early Silurian “Huaxia ancient land” to the west and northwest expansion coupling is the main factor leading to the area rose to land. A comprehensive analysis of the depositional discontinuities of the Ordovician-Silurian deposits in the entire Yangtze region requires further research work in multiple sections.