摘要
塔北隆起奥陶系大型油气田的发现促进了地质学家对该地区早古生代构造格局的探讨。早古生代不整合的地理、几何和时间变量解析有助于认识塔北古隆起的形成过程。基于大量的钻井和地震资料,解析了塔北隆起地区志留系底、顶部不整合,厘定了古隆起在晚奥陶世末和中泥盆世末的形态和展布范围,最终探讨了古构造应力场的演变。研究表明,塔北隆起地区志留系底、顶部不整合面都具有“下削上超”不整合结构,即不整合面之下的地层被削截,而年轻地层超覆于不整合面之上。隆起范围在晚奥陶世末期近东西向展布,而中泥盆世末期在南部斜坡上转变为3个古凸起(英买力低凸起、轮南低凸起、库尔勒鼻状凸起),整体上呈北东-南西向展布。晚奥陶世末近东西向的古隆起在中泥盆世末叠加了北东-南西向的构造,表明挤压应力场由晚奥陶世的南北向逐渐转变为北西-南东向。为已取得的关于塔北晚加里东期古隆起格局的认识提供了重要科学依据,并给予了详细的论证。
The discovery of the Ordovician giant oil and gas fields in the North Tarim Uplift has triggered heated discussion on the Early Paleozoic tectonic framework evolution.An analysis on the early Paleozoic unconformity in terms of geography,geometry,and temporal variables will facilitate the understanding of North Tarim Paleo-uplift development.Based on quantities of drilling and seismic data,this study analyzed the Silurian unconformities at the base and on top,determined the distribution and geometry of the paleo-uplift at the end of the Late Ordovician and the end of the Middle Devonian,and discussed the evolution of tectonic stress field.Both the Silurian unconformities at the base and on top are characterized by“truncation and onlap”,that is,the stratum below the unconformity was truncated while younger onlaps on the surface.The paleo-uplift struck nearly E-W at the end of the Late Ordovician,while NE-SW in the south slope region at the end of the Middle Devonian developed as three individual paleo-lower uplifts(i.e.,Yingmaili Lower Uplift,Lunnan Lower Uplift,and nose-shaped Korla Salient).The tectonic framework evolution(the near NS-trending structures superimposed by NE-SW folding)indicates that the compressive stress field changed from NS striking at the end of the Late Ordovician to NW-SE striking at the end of the Middle Devonian.In all,the results serve to provide essential evidence and detailed reasoning for the Late Caledonian tectonic framework of the North Tarim Uplift.
作者
陈槚俊
何登发
孙方源
田方磊
Chen Jiajun;He Dengfa;Sun Fangyuan;Tian Fanglei(School of Energy Resources,China University of Geosciences(Beijing),Beijing 100083,China;Key Laboratory of Marine Reservoir Evolution and Hydrocarbon Enrichment Mechanism(Ministry of Education),China University of Geosciences(Beijing),Beijing 100083,China)
出处
《石油与天然气地质》
EI
CAS
CSCD
北大核心
2021年第2期285-298,共14页
Oil & Gas Geology
基金
国家重点研发计划项目(2017YFC0601405-03)
国家科技重大专项(2017ZX05001-001)。
关键词
不整合面
古隆起
构造应力场
中泥盆世
晚奥陶世
塔北隆起
塔里木盆地
unconformity
paleo-uplift
tectonic stress field
Middle Devonian
Late Ordovician
North Tarim Uplift
Tarim Basin
