湖相油页岩的沉积环境及其层序地层学意义

DEPOSITIONAL ENVIRONMENTS OF LACUSTRINE OILSHALES AND ITS SEQUENCE STRATIGRAPHY SIGNIFICANCE

按照沉积环境，湖相油页岩可分为浅湖和深湖两种类型。前者可根据于盐湖模式、外因分层湖模式和浅盐湖模式来解释；后者则与分层湖作用有关。无论是浅湖还是深湖油页岩，在纵向上它们都位于湖侵－湖退旋回（规模可大可小）的中部。作为陆相地层中的“密集段”之一，油页岩是否可作为区分水进体系域和高水位体系域的标志（最大洪泛面或最大洪泛带），取决于它们在层序中所处的位置以及该油页岩层之上是否还有其他密集段的存在。

Lacustrine oil shales can be divided into shallow lake and deep lake deposits in termsof their sedimentary environments. The former can be playa, ectogenic meromictic andshallow saline lakes ; and the later is related to stratified lake. The oil shales are located inthe middle part of a transgressive-regressive cycle (whose scale is variable), whether theyare shallow or deep lake oil shales in origin. As one of condensated sections of continentalstrata, if oil shales can be marks between transgressive system tract and highstand systemtracts (the maximum flooding surface or the maximum flooding zone) depends on their position in the sequence and on if there is other condensated section above the shales.