A.W. Bally, 1983. "The Layered Earth—Introductory Comments", Seismic Expression of Structural Styles: A Picture and Work Atlas. Volume 1–The Layered Earth, Volume 2–Tectonics Of Extensional Provinces, & Volume 3–Tectonics Of Compressional Provinces, A. W. Bally
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Seismic sections almost always display significant examples of primary structures, that is structures that are primarily the product of sediment deposition or have an igneous origin, and that were not affected by later structural deformation. We, therefore, solicited a number of examples illustrating structurally undisturbed stratigraphic features, igneous structures, and the layering of the lower crust.
Section 112 of this atlas complements the many publications which have recently appeared on the subject of seismic stratigraphy. The reader should particularly refer to AAPG Memoir 26, edited by C.E. Payton, 1977. This classic volume will serve for some time as the foremost introductory text on the matter. In particular, we refer to the series of articles published by Gil et al (1977) on seismic stratigraphy and global changes of sea level. Additional material that highlights some of the geophysical aspects is offered by Anstey (1980), Neidell (1980), and Sheriff (1980).
Section 121 contains some high frequency profiles that offer a high resolution of stratigraphic and structural details. The reader is advised to initially focus on the paper by Bouma et al, because that paper provides an overview of the differences obtained by applying different high frequency techniques.
Section 122, on unconformities, 123 on illustrating sequences, 124 on carbonates, and 125 on clastics offer perhaps a somewhat artificial subdivision of various aspects of seismic stratigraphy.
Note that a number of profiles occurring in other sections of this atlas also contain very fine examples of seismic stratigraphy. This applies particularly to a number of papers in section 222 on rifts, 223 on passive margins, 224 on cratonic basins (atlas Volume 2), and some of the foredeep profiles included in section 341 on decollement tectonics (atlas Volume 3).
We obtained a number of profiles across various igneous structures (section 13) and would like to point out that there is an additional profile across a volcanic seamount in the paper by Lehner et al on the Tonga Trench (section 342, atlas plume 3).
Section 14 contains a profile across a presumed impact structure. We would like to obtain more examples of similar features, because of their importance for the evaluation of the current hypothesis on mass extinction (for a summary see McLaren, 1983, and Silver, 1982).
Section 15 includes a number of crustal profiles that were not easily included under some of the other subdivisions. But it should be noted that additional crustal profiles are presented in section 221 (atlas Volume 2), crustal profiles across extensional provinces, and section 321 (atlas Volume 3), crustal profiles across compressional provinces.