早古近纪陆相断陷型湖泊物质分异作用及其对“PETM”事件的响应:以济阳坳陷孔店组为例  

Material Differentiation and Its Response to the “PETM” Events in Continental Fault Lake during the Early Paleogene Period:A Case Study of Kongdian Formation in Jiyang Depression

作　　者：谭先锋[1,2,3] 王佳[1,3] 雷丽丹 况昊[1,3] 高红灿[1,3] 王伟庆[4] 

机构地区：[1]复杂油气田勘探开发重庆市重点实验室,重庆401331 [2]中国地质大学生物地质与环境地质国家重点实验室,湖北武汉430074 [3]重庆科技学院石油与天然气工程学院,重庆401331 [4]中国石化胜利油田分公司地质科学研究院,山东东营257015

出　　处：《地球科学（中国地质大学学报）》2016年第11期1893-1908,共16页Earth Science-Journal of China University of Geosciences

基　　金：国家自然科学基金项目(No.41202043);生物地质与环境地质国家重点实验室开放基金项目(No.GBL21506);中国石油科技创新基金项目(No.2014D-5006-0108);重庆市教委科学技术研究项目(No.KJ1401316)

摘　　要：古近纪早期,地球上发生了古新世-始新世极热气候(PETM)事件,严重影响全球碳循环过程和海陆生态环境系统.依据普通薄片、元素分析、碳同位素、TOC等实验结果.研究了渤海湾盆地济阳断陷湖盆古新世-始新世时期的湖泊环境时空波动变化及其对PETM事件的响应,发现济阳断陷湖盆早期经历了多旋回的演化过程,湖盆中碎屑物质和化学物质的分异作用同时发生,陆地风化作用和化学沉积物质分异指示了极热气候的变化过程;该时期湖水为逐渐咸化的盐湖环境,具有空间的分带性和时间的阶段演化性,湖水咸化是热气候事件发生的直接响应;湖泊的时空波动演化经历了古新世-始新世时期的极热气候(PETM)事件,该事件早期湖泊尚未完全咸化,浮游生物比较繁盛,早期浮游植物对12 CO2的吸收,会导致短暂的湖泊古生产力较高,但是随着湖盆逐渐咸化,生物的活动存活较难,主要以旱生植物为主,古生产力降到最低.由于过量的12 C吸收沉淀,造成湖泊沉积记录中的δ13 C明显负偏,最大可达5×10-3.由此证实全球PETM事件影响了古新世-始新世之交济阳断陷湖盆的时空演化和物质分异过程.Paleocene Eocene climate （PETM）events in Early Paleogene period on the Earth had serious impact on the global carbon cycle process and the terrestrial and marine ecological environment system.In this paper,on the basis of general thin-sections,elemental analysis ,carbon isotope,TOC et al.,the impact of Paleocene Eocene lake environment of Jiyang rifted ba-sin,Bohai bay on the temporal and spatial variation and response of ＂PETM＂is studied,and it is found Jiyang basin experi-enced early multicycle evolution processes,detrital material and chemical differentiation occurred at the same time in lacustrine basin,and terrestrial weathering and chemical sedimentary differentiation indicates the change of extreme climate.In this peri-od,the lake water experienced gradual salinization characterized by the spatial zoning and time-evolution stage,which is a direct response to the occurrence of hot climate events.Time-space evolution of the lake was subj ect to ＂PETM＂events.The lake was not fully salty in the early events with prosperous plankton.Early phytoplankton absorption of 12CO2 led to the higher produc-tivity in the ancient Lake,which dropped to a minimum with the lake turning increasingly salty and more difficult for the sur-vival.δ13C of lacustrine sedimentary records are in obvious negative bias due to excessive 12C absorption and precipitation,re-sulting in,a maximum of 5‰.It is confirmed that global ＂PETM＂events affected the time-space evolution and differentiation process of material in Jiyang depression during Paleocene-Eocene.

关 键 词：'PETM'事件 环境波动 陆相断陷湖泊 古近纪早期 济阳坳陷 石油地质. 

分 类 号：P618[天文地球—矿床学]