1、第3章 地層學Stratigraphy 3.1 概念、定律和地層的接觸關系3.1 Concepts, laws & contact relationships of strata3.2 地層劃分和對比3.2 Stratigraphic subdivision and correlation3.3 Stratigraphic units and geological times 3.4 地層的形成作用3.4 Stratigraphic formation13.1 概念、定律和地層的接觸關系 Concepts, laws & contact relationships of strata 3.1.

2、1 地層與地層學3.1.1 Strata and stratigraphy3.1.2 地層學的基本定律3.1.2 Basic stratigraphic laws3.1.3 地層的接觸關系3.1.3 Contact relationships of strata23.1.1 Strata & stratigraphyStrata: All layered rocks, which include all sedimentary rocks, a part of igneous rocks and metamorphic rocks地層:各種層狀巖石的統稱.包括所有的沉積巖,部分火成巖和變質巖.

3、layered(ICS,1994)3Rock cycles4Stratigraphy, from Latin stratum + Greek graphia, is the study of all rock bodies forming the Earths crust and their organization into distinctive, useful, mappable units based on their inherent properties or attributes in order to establish their distribution and relat

4、ionship in space and their succession in time, and to interpret geologic history. 地層學:研究層狀巖石形成的先后順序、地質年代、時空分布規律(狹義)和形成環境條件及其物理、化學性質的地質學分支學科.她的核心目標就是建立地球科學的時間坐標。Stratigraphy5太古宙+元古宙：12個GSSA顯生宙: 46+40=96個GSSPMa2004International stratigraphic chart63.1.2 地層學的基本定律3.1.2 Basic stratigraphic laws地層疊覆律(prin

5、ciple of superposition)原始水平律(Principle of original horizontality)原始側向連續律(principle of original lateral continuity) 由丹麥學者N. Steno(1638-1686)于1669年一次提出(Stenos stratigraphic axioms)7地層學三定律是構造地質學和地層學的基礎地層疊覆律: 原始地層自下而上是從老到新的(上新下老)原始水平律: 地層沉積時是近于水平的，而且所有的地層都是平行于這個水平面的(水平擺放).原始側向連續律: 地層在大區域甚至全球范圍內是連續的，或者延伸

6、到一定的距離逐漸尖滅(側向連續)。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 horizo

7、ntal 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. 相鄰 8美國科羅拉多州大峽谷國家公園9La

8、teral termination of stratal layersPinchout (c), Intertonguing (d), Lateral gradation (e)abNorth Island, New ZealandcdeAt edge of a depositional basin (a); Faulting followed by erosion (b)Sedimentary facies change with the depositional environments, while the fossils change mainly with time10濁積巖，C1,

9、 東天山11濁積巖，C1, 東天山12Way-upindicator13倒轉地層的識別方法(沉積學)ABC14倒轉地層的識別方法(沉積學)15化石層序律（Principle of fossil succession）不同時代的地層含有不同的化石，含相同化石的地層其時代相同。William Smith (1769-1839)-地層學之父于1817年提出。Principle of fossil Succession Fossils found in one rock layer will differ from layers above and below. By determining the

10、sequence of fossils in one location, it is possible to correlate rocks from another location if they contain the same fossils. 16化石定年J3三尾類蜉蝣J3-始祖鳥昆明魚神奇啰哩山蟲-具有成對眼睛和觸角的葉足動物古囊動物D3牙形石遼寧古果17Are you sure: there are the same fossils in the strata of the same geological time? Why?18相同時代的地層就一定含有相同的化石嗎？不一定1.

11、相同的時代可有不同的沉積環境2. 相同的時代也可有不同的埋藏和保存環境.19化石層序律的意義根據化石內容1 對比不同剖面的地層2 確定地層的相對順序及相對時間三剖面相距500KM20不整合平行parallel/discon.角度/angularDisconformity，假整合整合連續/continuity不連續discontinuity有地層缺失，上下地層產狀一致有地層缺失，上下地層產狀不一致上下地層之間沒有明顯的沉積間斷有沉積間斷 (hiatus/diastem), unconformityconformity非整合nonconformity沉積接觸depositional contact

12、侵入接觸intrusive contact地層與地層地層與其他地質體3.1.3 地層的接觸關系The contact relationships of strata21DS角度不整合的形成及意義Angular unconformity22昌平組景兒峪組Parallel unconformity/disconformity（北京西山）23explainedobserved24Conformity; D1 western Junggar25Nonconformity, 雞冠山, 北戴河沉積接觸:年輕的沉積蓋層直接覆蓋在較古老的巖漿巖或深變質巖上, 年輕沉積蓋層的底部常含下覆巖石的成分或礫石.侵入接

13、觸:年輕的巖漿侵入到較古老的地層中, 年輕巖體的邊緣常含來源于地層的捕虜體, 地層與巖體的交界部位常受到不同程度的烘烤.26地層接觸關系角度不整合 Angular unconformity非整合nonconformity平行不整合disconformity小間斷Paraconformity連續Continuity 27Be careful !200 km Contact relationships may change in space, from land to marine basin.28捕虜體Principle of Cross-cutting Relations ：A geologi

14、c 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. A B C D xenolith29Principle of Superpositi

15、on 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. Princip

16、le 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. Principles of Geology Principle of Cross-cutting Relations A g

17、eologic feature which cuts across or penetrates another feature must be younger than what it cuts. Principle of InclusionsRocks 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 Biologic Succession Foss

18、ils found in one rock layer will differ from layers above and below. By determining the sequence of fossils in one location, it is possible to correlate rocks from another location if they contain the same fossils. Unconformities are surfaces that represent gaps in the geologic record. Missing time - missing sediment Disconformity - uncon