地史学教学课件-地史学6.pptVIP

第3章 地层学Stratigraphy;3.1 概念、定律和地层的接触关系 Concepts,laws relationships between strata;3.1.1 Strata stratigraphy;Stratigraphy deals with order, geological times and distributional laws of strata in both temporal and spatial, physic and chemical features as well as formational environments conditions. 地层学:研究层状岩石形成的先后顺序、地质年代、时空分布规律(狭义)和形成环境条件及其物理、化学性质的地质学分支学科.目前已形成100余种地层学分支学科,如岩石、年代、生物、磁性、放射性地层学等;太古宙+元古宙：12个GSSA 显生宙: 46+40=96个GSSP;3.1.2 地层学的基本定律3.1.2 Basic stratigraphic laws;地层学三定律是构造地质学和地层学的基础;North Island, New Zealand;;浊积岩，C1, 东天山;Way-upindicator;倒转地层的识别方法(沉积学);倒转地层的识别方法(沉积学);化石层序律—Principle of fossil succession;化石定年;化石层序律的理论依据;Organisms from the North Island, New Zealand; 北戴河;相同时代的地层就一定含有相同的化石吗？为什么？;相同时代的地层就一定含有相同的化石吗？不一定;化石层序律简图;整合接触：连续和小间断。 不整合接触：角度不整合、平行不整合（假整合）;沉积接触和侵入接触.; 地层间的连续:沉积作用没有发生中断, 地层特征相同. 地层的间断: 沉积作用有中断，但是没有明显的大陆剥蚀作用，常为岩性的截然变化。连续的地层和具间断的地层都属整合接触。;不整合接触-unconformity;disconformity（北京西山）;平行不整合（北京西山）;平行整合的形成及其意义;角度不整合的形成及意义;;Nonconformity, 鸡冠山, 北戴河;地层接触关系;Principle of Cross-cutting Relations ：A geologic feature which cuts across or penetrates another feature must be younger than what it cuts. Principle of Inclusions：Rocks which contain inclusions of another rock are younger than the inclusion. The inclusion is older than the rock in which it is included. ;Principle of Superposition In any sequence of undisturbed strata (rock layers), the oldest layer is on the bottom and the youngest is on the top. Principle of Original Horizontality Sediments settle from fluids under the influence of gravity, therefore the deposits are nearly horizontal or at very shallow inclines. Principle of Lateral Continuity A water-laid stratum, at the time it was formed, must continue laterally in all directions until it thins out as the result of nondeposition or until it abuts against the edge of the original basin of deposition. ;The end of Stratigraphy-1