干旱区生态环境知识资源中心(Arid): 川西南构造复杂区龙马溪组泥页岩地球化学特征及古环境

Arid

	川西南构造复杂区龙马溪组泥页岩地球化学特征及古环境
其他题名	Geochemical Features and Paleoenvironment of Shales in Longmaxi Formation of Complicated Structure Area, Southwestern Sichuan Basin
	张茜 1; 王剑 2; 余谦 1; 王小飞 1; 赵安坤 1; 雷子慧 3
来源期刊	新疆石油地质
ISSN	1001-3873
出版年	2017
卷号	38 期号:4 页码:399-406
中文摘要	深入研究川西南构造复杂区下志留统龙马溪组泥岩沉积环境,指导区域页岩气的勘探开发,对该地区荥经县泥巴山剖面龙马溪组泥岩进行系统采样,开展了元素地球化学研究。结果表明,研究区平均化学蚀变指数为68,略低于世界页岩的平均化学蚀变指数70,Th/U为3.73,与大陆地壳Th/U平均值3.80接近,表明物源区曾遭受低中度风化;较高含量的易水解元素、铁族元素及较低含量的亲硫元素,表明沉积水体为滨浅海环境。氧化还原指标deltaU,U/Th,V/Cr及Ni/Co均说明沉积水体为弱氧化环境,且越到龙马溪组沉积晚期氧化性越强。古气候指标Sr/Cu说明源区沉积期气候干旱,古盐度指标Sr/Ba,B/Ga说明研究区龙马溪组为半咸水海相沉积。研究区总有机碳含量较低,且与风化指标、氧化还原指标、古盐度古气候指标均有较好的相关性,说明总有机碳含量受沉积环境的控制。研究区龙马溪组为一套深水浅水陆棚相烃源岩,受沉积环境及构造隆升的影响,其下段有机质品质相对较好,上段品质较差。
英文摘要	The paper studies the sedimentary environment of the shales in the Lower Silurian Longmaxi formation of the complicated structure area in the southwestern Sichuan basin, and provides guidance for shale gas exploration and development in the area. Based on the systematic sampling of shales in Longmaxi formation on Niba Mountain section in Yijing county, geochemical studies are carried out. The results show that the average value of Chemical Index of Alteration(CIA)in the study area is 68, which is slightly lower than that of the shales in the world (CIA=70), and the average Th/U ratio in the study area is 3.73, which is close to the average value 3.80 of the continental crust, indicating that the provenance suffered from weak-medium weathering. Relative high content of hydrolysable and ferrum and relative low content of sulfophilic elements show that the sedimentary water was shore-shallow sea environment. The redox indexes such as deltaU, U/Th, V/Cr and Ni/Co indicate a weak oxidation environment of the sedimentary water, and an even stronger oxidation environment at the late deposition stage of Longmaxi formation. The paleoclimatic indicator Sr /Cu indicates an arid climate during the deposition of the provenance and paleosalinity indicators Sr/Ba and B/Ga indicate Longmaxi formation is brackish marine deposition. The TOC in the study area is relatively low and well correlates with the indicators of weathering, redox, paleosalinity and paleoclimate, which indicates that the TOC is controlled by sedimentary environment. Longmaxi formation in the study area is a set of source rocks of deep watershallow water shelf facies, and the lower Longmaxi formation is of good quality and the upper section is relatively poor due to the influence of sedimentary environ- ment and tectonic uplift.
中文关键词	川西南 ; 构造复杂区 ; 龙马溪组 ; 泥页岩 ; 地球化学 ; 古环境
英文关键词	southwestern Sichuan basin complicated structure area Longmaxi formation shale geochemistry palaeoenvironment
语种	中文
国家	中国
收录类别	CSCD
WOS类目	ENERGY FUELS
WOS研究方向	Energy & Fuels
CSCD记录号	CSCD:6047319
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/236863
作者单位	1.中国地质调查局成都地质调查中心, 成都, 四川 610081, 中国; 2.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, 成都, 四川 610081, 中国; 3.中国地质大学地球科学学院(武汉), 武汉, 湖北 430074, 中国
推荐引用方式 GB/T 7714	张茜,王剑,余谦,等. 川西南构造复杂区龙马溪组泥页岩地球化学特征及古环境[J],2017,38(4):399-406.
APA	张茜,王剑,余谦,王小飞,赵安坤,&雷子慧.(2017).川西南构造复杂区龙马溪组泥页岩地球化学特征及古环境.新疆石油地质,38(4),399-406.
MLA	张茜,et al."川西南构造复杂区龙马溪组泥页岩地球化学特征及古环境".新疆石油地质 38.4(2017):399-406.