EFFECTS OF EPISODIC DIFFERENTIAL SUBSIDENCE ON THE CHANGES OF LAKE LEVEL AND WATER DEPTH IN RIFT LAKE BASINS
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摘要: 湖平面(相对和绝对)和水深是控制湖盆沉积作用的两个基本参数。在断陷湖盆中,由于盆地边界断层的幕式活动,导致盆地缓坡带基底发生差异沉降,相对湖平面、绝对湖平面和水深等参数可出现不统一的变化,主要表现在以下两个方面:a)相对湖平面、绝对湖平面和水深3个参数间出现不统一性变化;b)相对湖平面或水深在湖盆的不同构造位置出现不统一性变化。即在同一沉积时间单元内,湖盆中水深既有增加带也存在减小带,或者相对湖平面既存在上升带也存在下降带;但是绝对湖平面对于同一湖盆来说具有统一性变化。幕式差异沉降运动控制了盆地可容空间的变化,这种非统一性变化是某段时间内新生可容空间量(△Va)与外界水净流入量(△Vw)和沉积物充填量(△Vs)3个参数的综合响应。特别当△Va>△Vw+△Vs时,基底差异沉降运动引起湖盆出现强制性湖退作用,形成层序界面。Abstract: Relative and absolute lake level and water depth are two essential parameters controlling lake-basin sedimentation. In a rift lake basin, the differential subsidence of basement in the gentle slope zone of the basin resulted from the episodic movement of boundary faults in the basin can lead to the discordant changes of relative and absolute lake level, water depth and other parameters, that is, the discordant changes of relative lake level, absolute lake level and water depth and those of relative lake level or water depth at different structural location of the lake basin. In the same sedimentary time unit, the water depth of a lake basin had both increasing and decreasing zones, or not only rising but also falling zones existed in relative lake level; but the absolute lake level to the same lake basin had concordant changes. Episodic diffe-rential subsidence controlled the changes of accommodating space in a basin. This kind of discordant changes were the comprehensive response of the neogenic volume of accommodating space(△Va), the net incurrent volume of external water(△Vw)and the infilling volume of sediments(△Vs)three parameters du-ring a certain period of time. Especially when △Va>△Vw>△Vs, the differential subsidence of basement resulted in forced regression in a lake basin and formed sequence interfaces.
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Key words:
- accommodating space /
- sequence stratigraphy /
- lake level /
- differential subsidence /
- rift lake basin
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[1] Wheeler H E. Base level, lithosphere surface, and time-stratigraphy[J]. GSA Bulletin, 1964, 75(5):599-610. [2] 池英柳. 可容纳空间概念在陆相断陷盆地层序分析中的应用[J]. 沉积学报, 1998,16(4): 8-13. [3] 胡受权. 泌阳断陷双河-赵凹地区下第三系核三上段陆相层序发育的可容空间机制[J]. 沉积学报,1998,16(3):102-108. [4] 肖焕钦, 陈广军, 李长宝. 济阳坳陷盆地拉张量及其石油地质意义[J]. 石油实验地质,2002,24(1):13-18. [5] 解习农, 程守田, 陆永潮. 陆相盆地幕式构造旋回与层序构成[J]. 地球科学, 1996, 21(1):27-33. [6] Van Wagoner J C,Mitchum R M, Campion K M, et al. Siliciclastic sequence stratigraphy in well logs,cores,and outcrops: concepts for high-resolution correlation of time and facies[J]. AAPG Methods in Exploration Series 7,1990. 55. [7] 董清水, 崔宝琛, 李想, 等. 陆相层序地层划分及岩心、测井高分辨率层序地层界面判识[J]. 石油实验地质,1997,19(2):121-126. [8] Posamentier H W, Allen G P, James D P, et al. Forced regressions in a sequence stratigraphic franework: concepts,examples and exploration significance[J]. AAPG Bulletin, 1992,76: 1687-1709. [9] 纪友亮, 张世奇, 等. 层序地层学原理及层序成因机制模式[M]. 北京: 地质出版社, 1998.
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