| Silurian in the known geological time, although shorter duration, but still has a very important research implication. The Yangtze region is a typical area in China. The paper selects the Llandovery series in northern Guizhou as the research site,and focuses on outcrop sequence analysis. Through the field investigation and measurement, combined with previous research results, the paper has achieved the expected results, including the following aspects:1. To preciously chronostratigraphy, biostratigraphy, lithostratigraphy and sequence stratigraphy data collection and analysis, according to Shiqian and Zheng’an profile data, determine the Silurian chronostratigraphic classification scheme, discuss the distribution features of the lithostratigraphic in the area, the top of Longmaxi formation have obvious diachroneity.2. Base on the outcrop survey, measurement and analysis, combined with the corresponding chronostratigraphy, biostratigraphy and lithostratigraphy, the paper divided Silurian in the study are into six 3rd-order sequences Sq1- Sq6: Longmaxi formation(Sq1), the lower Shiniulan formatio(SQ2), the upper Shiniulan formation(SQ3), Rongxi formation(Sq4), the lower Xiushan formation(SQ5), the upper Xiushan formation(Sq6).The paper focuses on SQ1-SQ3 sequence. Describe the key part to high-frequency sequence analysis.3. Northern Guizhou Longmaxi formation mainly deposited in shelf, the lower part main deep shelf environment, upward shoaling to shallow shelf, and compared with Shiniulan formation the sedimentary environment and lithology changed greatly, and the sedimentary thickness northward. Shiniulan formation is carbonate platform and the thickness appeared a northward eastward thickening, from the south to the north, followed by the restricted platform, platform margin slope to platform margin reef phase. The temporal and spatial variation of Sq1 – Sq3 sequence was analyzed by the integrated sedimentary environment and the ancient geographical features. |
PDF Full Text Request