【作者】 何逢阳；

【导师】 陈义才；

【作者基本信息】 成都理工大学 ， 矿产普查与勘探， 2010， 硕士

【摘要】 应用沉积学、层序地层学的原理,根据野外露头剖面、钻井、取芯、测井、录井、地震等资料,采用传统野外、室内和现代化测试手段相结合的研究方法,对川中地区须家河组与珍珠冲段的沉积特征进行了系统的研究,明确了珍珠冲段底界面上下地层的沉积变化特征,为川中地区须家河组与珍珠冲段的地层界线的确定提供了古生物化石、测井等重要依据。川中地区须家河组和珍珠冲段古植物都是以裸子植物的苏铁类和蕨类植物为主,但属种发育有所不同。须六段上部黑色页岩富含植物化石,且保存完好,特征明显;而珍珠冲段一般不含完整的植物化石,只见少量炭化植物碎屑。珍珠冲段底部的石英质砾岩、石英砂岩是这一界线较好的岩性标志。通过大量的野外露头和岩芯观察,发现须家河组地层中发育大量的近海潮汐沉积构造与层理,如双粘土层、水流突变、脉状层理、透镜状层理等。综合研究认为须家河晚期川中地区主要属于浅海河口湾相,包括河口坝、潮汐影响的三角洲、河口湾泥、潮间与潮上带等环境。珍珠冲段地层中见植物根系、菱铁矿小颗粒、强烈的生物扰动、平行层理等特征,揭示了珍珠冲期川中地区为滨湖湖泊三角洲沉积环境,只在局部地区可能受海洋潮汐影响。地震反射终端特征分析表明珍珠冲段底面截削了须六段,而珍珠冲段底部则上超于该界面上,揭示了珍珠冲段底面为一不整合面,沉积在一轻微削蚀了的风化面之上。研究区内须六段下部的测井响应特征主要为箱型,上部主要为漏斗状、花瓶状、叠置漏斗状等形态;而珍珠冲段的测井响应特征主要为钟形、叠置小漏斗、花瓶状等形态。通过地层拉平连井剖面对比分析,须家河至珍珠冲时期地形起伏被沉积补偿迅速填平,揭示了川中地区须家河期与珍珠冲期构造运动和缓平稳,为东岳庙期区域性大湖泊的出现创造了条件。通过川中东北部地区14口井的岩屑记录的研究,总结了界线上下附近的须家河组与珍珠冲段岩屑差异,划分出8种岩屑组合类型。综合野外、岩芯、录井、测井等资料,从颜色、古生物、沉积构造、成岩后生矿物、测井曲线形态等方面总结了川中地区须家河组与珍珠冲段的地层划分标志,采用可靠的对比方法对研究区内须家河组与珍珠冲段地层进行划分对比。更多还原

【Abstract】 By applying of the principles and methods of Sedimentology and Sequence Stratigraphy, based on field outcrops, drilling, coring, logging, logging, and seismic data for the study, adopted the ways of combination traditional outdoor, indoor, and modern testing methods, this paper made a deeper study on the sedimentary of Xujiahe formation and Zhenzhuchong member in the middle of Sichuan region. Made analysis and comparison on the interface changes of Xujiahe formation and Zhenzhuchong member in this area, this provides an important basis for identify the boundary line between Xujiahe formation and Zhenzhuchong member.The fossil plants in the study horizon are gymnosperms almost, dominated by cycads and ferns, but the general and species developed differently. The black shale rich in plant fossils in the upper of the sixth member of Xuejiahe formation, and preserved well foe identification; the Zhenzhuchong member doesn’t contain complete plant fossils generally, but saw a small amount of carbonized plant debris. The quartz sandstone and quartzose sandstone in the bottom of the Zhenzhuchong member is the lithologic mark of this boundary.Through a large number of outcrop and core observations, found that there are lots of offshore tidal sedimentary structures and bedding, such as bi-clay layer, flow mutation, vein bedding, lenticular bedding, etc. This show that in the later period of Xujiahe in the study area are mainly shallow estuarine facies, including the mouth bar, tidal effects of delta, estuary mud, with the tide on the intertidal zone and other environment. And the Zhenzhuchong member contains plant roots, small siderite particles, strong bioturbation, parallel bedding and other features, reveals that in the period of Zhenzhuchong the middle of Sichuan region is lake delta, and in the northeast area, there are delta front , shunt between the Gulf and the former delta sediments. Ocean tides perhaps make some influences in some areas. The seismic reflection show that the bottom of the J1z cut-off the T3x6, while the bottom of the J1z extrudoclusion this interface, revealed the bottom of the J1z is an unconformity surface, deposited on a land surface which was slightly denudation.The typical logging response characteristics of xujiahe formation is Box-shaped and the upper of T3x6 are funnel-shaped,vase-shaped,overlay funnel-shaped,and so on.But Zhenzhuchong member response characteristics of the main section of the log for the bell-shaped, stacked small funnel, vase-shaped and other forms.in the profile of the connected wells’ profile,Compensation for terrain quickly filled by deposition at the age of T3x～J1z. Reveal Sichuan gentle tectonic movement smooth, no specific long-term uplift or subsidence areas, large lakes for the temple has the appearance of regional and create the conditions. Research on 14 Cutting loggings in the northeast of central sichuan,compared the defference of the upper and lower boundary near the Xujiahe formation and zhenzhuchong member. Research on the cutting loggings of the upper and lower of the boundaries of Xujiahe formation and zhenzhuchong member ,the result and combinations are many and varied.According to field section,core,logging,et at al, summarizes the differences in the color, paleontology, sedimentary structures, diagenetic epigenetic minerals, logging curve shaped morphology, etc between the upper and lower boundary near the Xujiahe formation and zhenzhuchong member.更多还原