地层学 Stratigraphy
（重定向自Hydrostratigraphy）
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![地球外观](/Images/godic/202501/19/The_Earth_seen_from_Apollo_173052.jpg")
![](/Images/godic/202501/19/Earth-crust-cutaway-english3052.png")
![Deformación tectónica de los estratos cuarcíticos ordovícicos del Parque nacional de Monfragüe, Cáceres (España).](/Images/godic/202501/19/Stratigraphy-Monfragüe3053.jpg")
地层学是地质学的一个分支，是地质学的基础学科，是在19世纪初发展起来的一个学科，最早用于研究沉积岩和火山喷出的层序。现在的研究包括地层的时代和地理分布，地层的分类，各种岩石之间的关系等。地层学根据主要研究对象不同可以分为岩石地层学、生物地层学和年代地层学。
Hydrostratigraphy
中文百科
英语百科
Stratigraphy 地层学
（重定向自Hydrostratigraphy）
![The Permian through Jurassic strata of the Colorado Plateau area of southeastern Utah demonstrate the principles of stratigraphy.](/Images/godic/202501/19/SEUtahStrat3053.JPG")
![Engraving from William Smith's monograph on identifying strata based on fossils](/Images/godic/202501/19/Smith_fossils13053.jpg")
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![Chalk layers in Cyprus, showing sedimentary layering](/Images/godic/202501/19/Geology_of_Cyprus-Chalk3053.jpg")
Stratigraphy is a branch of geology which studies rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy includes two related subfields: lithologic stratigraphy or lithostratigraphy, and biologic stratigraphy or biostratigraphy.