台地相剖面不同时期海平面早期上升相对快慢的评估方法  

A Method Evaluating the Relative Rate of Early-stage Rise in Cycles of Sea-level Changesat a Platform Section Based on the Stratum Thickness

作　　者：刘家润[1] 杨湘宁[1] 施贵军[1] 

机构地区：[1]南京大学地球科学系,江苏南京210093

出　　处：《南京大学学报（自然科学版）》2004年第6期649-658,共10页Journal of Nanjing University（Natural Science）

基　　金：国家自然科学基金 ( 40 0 72 0 0 8;4 0 4 72 0 2 1 )

摘　　要：理论推导结果表明 ,在无剥蚀且沉积速率 (VS)和压缩比 (C)不变的条件下 ,碳酸盐台地相剖面点处三极相对海平面早期上升速度 (VR1 )与三级沉积层序厚度 (Sd)、海侵体系域及陆架边缘体系域厚度 (Td +Md)和老空间增量 (Δko)之间 ,具有近似关系式 :VR1 ≈CVSSd +ΔkoTd +Md.据此 ,可应用剖面层序地层比值R( =Sd +ΔkoTd +Md) ,来定量化评估台地相剖面中无剥蚀、无凝缩段若干三级沉积层序所代表的不同时期相对海平面早期上升的相对快慢 ;当某个或某些沉积层序的R值相对于其它沉积层序的R值较大时 ,则表明这个或这些沉积层序形成时期的相对海平面早期上升相对较快 ,反之亦然 ;If the sedimentary rate (V_S) and compressive ratio (C) are constant without erosive actions in the sedimentary process, it can be deduced that there is an approximate relation represented by V_(R_1)≈CV_SSd+Δk_oTd+Md, in which V_(R_1) is the rise rate of the early stage in the 3^(rd)_grade cycle of relative sea_level changes; Sd the thickness of the 3^(rd)_grade depositional sequence at a platform section;Td and Md respectively the thickness of transgression systems tract and shelf_margin systems tract in the sequence; and Δk_o the increment of old space. Based on the deductive results, we can make use of the value of ratio R(=Sd+Δk_oTd+Md) to evaluate the relative rate of early_stage rise in the different 3^(rd)_grade cycles of relative sea_level changes. The R values of different sequences in a platform section without concentrative deposition and erosive evidence might respectively represent the different rates of early_stage rise in different cycles. And the bigger the R value is, the faster the rise rate may be.

关 键 词：碳酸盐台地 层序地层 海平面变化 早期上升速率 评估方法 

分 类 号：P534[天文地球—古生物学与地层学]