摘要
火石岭组是松辽盆地早期断陷充填的第一套序列,也是国际大陆科学钻探松科2井的主要目的层之一。松科2井2018年完钻后是否钻遇火石岭组一直存在争议。地质-地球物理资料综合分析表明,松科2井钻遇了火石岭组,井深5613.41~5959.84m,厚346.43m,以高含量的火山物质为特征,顶部以凝灰岩层与上覆沙河子组为界;GR和RRD曲线呈现较大的起伏和不稳定的特征;地震上表现为同相轴连续性好、振幅强、频率较高的特征;沉积-充填速率显著小于沙河子组。将火石岭组定义为不整合于基底之上,与上覆沙河子组(局部与营城组、登娄库组或泉头组)呈整合/不整合接触的第一套火山-沉积充填序列,代表了断陷早期火山活动较为强烈的一个阶段。松辽盆地断陷期充填演化,北部和西部受控于北部蒙古-鄂霍茨克构造体系,中部和东南部受控于东部环太平洋构造体系。控陷构造体系差异、板块俯冲的距离效应以及岩浆中心的迁移等,是各断陷发育时间、发育规模、火山-沉积充填时间和规模等时空差异的根本原因。松辽盆地断陷期总体经历了火石岭组和营城组火山-沉积建造夹沙河子组火山平静期陆源碎屑沉积的过程,但不同部位断陷启动时间、各组充填时间和充填序列又存在显著差异:断陷启动时间和沙河子组开始沉积时间具有北部早、南部次之、中部最晚的特点;火石岭组火山-沉积建造在盆内广泛分布,而营城组火山-沉积建造主要分布于盆地中部。松辽盆地断陷期相同组段可能不具有统一的同位素年龄,直到营城组之后(约103~104Ma),盆地断陷演化阶段结束,整个盆地同时坳陷沉降,各个组段形成统一的时间格架。
The Huoshiling Formation(HF)is the first basin filling sequence of the Songliao Basin during the fault depression stage.It is also one of the primary target formations of the International Continental Scientific Drilling Program SK2.Considerable debate persists regarding whether the SK2 Well penetrated the HF after the completion of drilling in 2018.The depth of the HF in SK2 ranges from 5613.41m to 5959.84m,with a thickness of 346.43m,and it is marked by a layer of tuff,which serves as the boundary with the overlying Shahezi Formation(SF).The HF in SK2 is characterized by a high content of volcanic materials and mainly consists of pyroclastic rocks,sedimentary pyroclastic rocks,and volcaniclastic sedimentary rocks.The GR and RRD curves of the HF in SK2 show significant fluctuations and unstable characteristics;seismic data exhibit good continuity of cophasal axes,strong amplitudes,and high frequencies;and the sedimentation-filling rate is significantly lower than that of the SF.The HF is now defined as the first volcanic-sedimentary filling sequence that is unconformity on the basement,and overlain by the SF,or locally by Yingcheng(YF)/Denglouku/Quantou formations,exhibiting either conformable or unconformable contacts.It represents an early stage of intense volcanic activity in the fault depression stage.The evolution of fault depressions in the northern and western parts of the Songliao Basin is controlled by the northern Mongol-Okhotsk tectonic regime,while the evolution of depressions in the central and southeastern parts is controlled by the eastern Circum-Pacific tectonic regime.Differential tectonic regimes,the distance effect of plate subduction,and the migration of magma centers are essential reasons for the spatiotemporal variations in the initiation time and scale,as well as the volcanic-sedimentary filling and scale in fault depressions in the Songliao Basin.The basin fillings of the Songliao Basin during the fault depression stage overall experienced processes of volcanic-sedimentary construction,including the HF and YF,which were sandwiched between a volcanic quiescence period represented by the SF and terrestrial clastic sedimentation.However,there are significant differences in the initiation time,basin filling duration,and filling sequence of the fault depressions.The initiation time of the fault depressions and the onset of sedimentation of the SF in the Songliao Basin exhibit the characteristic of being earliest in the north,followed by the south,and latest in the central part.The volcanic-sedimentary construction of the HF is widely distributed within the basin.While the volcanic-sedimentary construction of the YF is mainly concentrated in the central part of the basin.The stratigraphic unit of the fault depression stage in the Songliao Basin may exhibit variability in isotopic ages.Since the end of the YF(ca.103~104Ma),the fault depression stage of the basin ended,and the entire basin began to subside uniformly,establishing a consistent temporal framework for each stratigraphic unit thereafter.
作者
瞿雪姣
张琪
王璞珺
刘硕
万晓樵
吕大炜
王佳
谭先锋
QU XueJiao;ZHANG Qi;WANG PuJun;LIU Shuo;WAN XiaoQiao;LV DaWei;WANG Jia;TAN XianFeng(School of Petroleum Engineering,Chongqing University of Science and Technology,Chongqing 401331,China;School of the Environment,University of Queensland,Brisbane 4072,Australia;College of Earth Sciences,Jilin University,Changchun 130061,China;State Key Laboratory of Biogeology and Environmental Geology,China University of Geosciences,Beijing 100083,China;Shandong University of Science and Technology,Qingdao 266590,China)
出处
《岩石学报》
北大核心
2025年第9期3209-3224,共16页
Acta Petrologica Sinica
基金
国家自然科学基金项目(42102135、42202122、42072140)
重庆市杰出青年科学基金项目(CSTB2022NSCQ-JQX0031)
重庆市自然科学基金面上项目(CSTB2022NSCQMSX1586)
重庆市教育委员会科技重大项目(KJZD-M202101502)
重庆科技大学科学研究项目(20240324)
重庆科技大学研究生创新计划项目(YKJCX2420115)
国家留学基金管理委员会项目(202208505055)联合资助.
关键词
松辽盆地
断陷期
盆地充填
松科2井
火石岭组
Songliao Basin
Fault depression stage
Basin filling
SK2
Huoshiling Formation
