渝东北地区观音桥段沉积与有机碳同位素特征及其区域对比

发布时间：2018-06-01 00:28

  本文选题：观音桥段 + 五峰组—龙马溪组　； 参考：《地质学报》2017年05期

【摘要】：渝东北地区五峰组—龙马溪组间观音桥段厚度不一、沉积特征各异,自西向东对庙坝渝参1井(YC1)、田坝剖面(TBP)、白鹿剖面(BLP)、九湖四方洞剖面(SFP)和巴东两河口(LHP)剖面的分析表明,观音桥段以发育浅灰色中—薄层状泥质灰岩为主,局部为含介壳泥灰岩层,且强烈风化后常呈褐黄色、土黄色。研究区内两河口剖面为灰黑色泥质灰岩,也发育介壳化石,四方洞剖面观音桥段表现为粉砂质含量的明显增多。仅田坝剖面和两河口剖面见赫南特贝化石印模。各剖面有机碳同位素垂向演化特征相似,具有区域及全球对比性;在赫南特期观音桥段均表现出明显的碳同位素正漂以及峰值,可能受局部环境影响,其正漂幅度不尽相同;五峰组至观音桥段碳同位素呈震荡性升高,可出现短暂的小型峰值;观音桥段至龙马溪组,碳同位素呈现持续稳定的下跌,下跌速度取决于龙马溪组厚度。
[Abstract]:The thickness and sedimentary characteristics of Guanyinqiao member between Wufeng formation and Longmaxi formation in northeast Chongqing are different. The analysis of YC1, TBPU, Bailu, SFPFPand LHP) sections of Miaoba-Chongqing 1 from west to east of Miaoba-Yu-1, Bailu, Sixiangdong and LHP) shows that, Guanyin Bridge section is mainly composed of grayish meso-thin-layer shaly limestone, which is mainly composed of meso-shell mudstone layer, and it is usually brown-yellow and khaki-yellow after strong weathering. Lianghekou section in the study area is composed of gray black mudstone and fossils. The Quanyinqiao section of Sixiangdong section shows an obvious increase in silty sand content. Only Tianba section and Liangkou section see Hernantebe fossil impression. The vertical evolution characteristics of organic carbon isotopes in different sections are similar and have regional and global contrasts, and there are obvious positive drift and peak values of carbon isotopes in Guanyinqiao section of Hernant period, which may be affected by local environment, and their positive drift ranges are different. The carbon isotopes from Wufeng group to Guanyinqiao section are oscillating, and there can be a short peak value, while from Guanyin bridge section to Longmaxi formation, the carbon isotope shows a steady decline, and the falling speed depends on the thickness of Longmaxi formation.
【作者单位】： 成都理工大学地球科学学院;中国地质调查局成都地质调查中心;国土资源部沉积盆地与油气资源重点实验室;
【基金】：四川盆地页岩气基础地质调查项目(DD20160176) 重庆市页岩气专项地质调查(渝东北)项目 重庆市页岩气勘探有利区带优选及资源量评价研究(渝东北)项目 国家自然科学基金项目(编号41672112;41402103)共同资助成果
【分类号】：P597;P618.13
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本文编号：1962042