干旱区生态环境知识资源中心(Arid): 济阳坳陷古近纪页岩形成的孢粉响应特征

Arid

	济阳坳陷古近纪页岩形成的孢粉响应特征
其他题名	RESPONSE OF SPORE-POLLEN TO THE FORMATION OF PALEOGENE SHALE IN THE JIYANG DEPRESSION
	贺振建; 张存霞; 李慧; 何青芳; 赵慧
来源期刊	第四纪研究
ISSN	1001-7410
出版年	2015
卷号	35 期号:3 页码:660-668
中文摘要	根据孢粉化石恢复的古气候,济阳坳陷古近系沙河街组沉积时期为亚热带气候,沙河街组四段上亚段、三段下亚段和沙河街组一段沉积时期,气候处于由干旱向潮湿转换时期,藻类勃发,水体仍具一定盐度,是最有利于页岩发育的气候。济阳坳陷沙四上和沙三下页岩中有机质丰度高,有机质类型以腐泥型为主,孢粉化石相对贫乏,孢粉相对密度与有机碳有呈负相关的趋势。区域上,目前钻探页岩厚度较大的井都分布在孢粉相对密度低的地区,且紧邻高值区,据此可确定页岩发育有利区域应该在孢粉相对密度较高的两侧、前方至深湖区。
英文摘要	Shales are well developed in the upper part of fourth member (Es_4~u),the lower part of third member (Es_3~1), and the first member of the Shahejie formation (Es_1) of Paleogene age in the Jiyang Depression. Based on the sporepollen assemblage, the climate was subtropical in the Jiyang Depression when the Shahejie Formation was deposited. In particular, Es_4~u,Es_3~1 and Es_1 were deposited when the climate experienced a transition from dry to wet conditions. So when organic matter began to accumulate in large quantity, the lake still had certain salinity and multiple stratifications that favored shale formation. This suggests that the lake stratification in favor of shale formation in Paleogene was controlled by both temperature and salinity,whereas salinity was also related to climate,pointing at a climate controlling mechanism for the deposition laminated shales. The spore-pollen assemblages were monotonous during the lower part of fourth member of Shahejie Formation. The assemblages were characterized by high content of Ephedripites of drought condition, suggesting an arid climate unfavorable for organic matter accumulation and shale formation. During Es_4~u-Es_3~1 periods, Ephedripites reduced gradually, while Quercoidites and Taxodiaceaepollenites of wet condition increased, and shales began to develop. During the middle period of the third member of Shahejie Formation, Quercoidites continued to increase and reached its peak during the entire Shahejie Formation sedimentary period, but the lake became fresh and unfavorable for shale formation. Ephedripites showed a small peak during the late period of the second member of Shahejie Formation. The climate gradually turned from dry to wet when entering the Es_1 period, Quercoidites dominated the pollen assemblage, and shales began to develop. Because the spores and pollen in lake are mostly derived from terrestrial environment via surface runoff or river transport, abundant pollen are found at places where the lake water is relatively turbulent, a condition unfavorable for shale formation. However, surface runoff or rivers can also bring a lot of nutrients into lakes and cause algae bloom that favors shale formation. Thus, the areas favorable for shale development include the riversides, river end to deep lake where the influence of hydrodynamic force is weak. The shales in Es_4~u and Es_3~1 in the Jiyang Depression contain abundant organic matter mainly of sapropel type, and scarce spores and pollen. The spore-pollen density (number of spores and pollen per cover-glass) is negatively correlated with organic carbon content. To date, wells drilled with thick shales are located in regions with relatively low spore-pollen density, but close to regions with high density of spores and pollen. Therefore, we can use spore-pollen density data to delineate regions favorable for shale development, which should lie in areas from the both sides or the front of high spore-pollen density to deep lake. This preliminary delineation is consistent with current exploration deployment, highlighting the use of sporepollen data in future hydrocarbon exploration.
中文关键词	孢粉 ; 相对密度 ; 气候 ; 页岩 ; 古近纪 ; 济阳坳陷
英文关键词	spore-pollen relative density climate shale Paleogene Jiyang Depression
语种	中文
国家	中国
收录类别	CSCD
WOS类目	PALEONTOLOGY
WOS研究方向	Paleontology
CSCD记录号	CSCD:5425106
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/232560
作者单位	中石化股份胜利油田分公司地质科学研究院, 东营, 山东 257015, 中国
推荐引用方式 GB/T 7714	贺振建,张存霞,李慧,等. 济阳坳陷古近纪页岩形成的孢粉响应特征[J],2015,35(3):660-668.
APA	贺振建,张存霞,李慧,何青芳,&赵慧.(2015).济阳坳陷古近纪页岩形成的孢粉响应特征.第四纪研究,35(3),660-668.
MLA	贺振建,et al."济阳坳陷古近纪页岩形成的孢粉响应特征".第四纪研究 35.3(2015):660-668.