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Role of water in the formation of the Late Cretaceous Wetumpka impact structure, inner Gulf Coastal Plain of Alabama, USA
Author(s) -
King David T.,
Ormö Jens,
Petruny Lucille W.,
Neathery Thornton L.
Publication year - 2006
Publication title -
meteoritics and planetary science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.09
H-Index - 100
eISSN - 1945-5100
pISSN - 1086-9379
DOI - 10.1111/j.1945-5100.2006.tb00440.x
Subject(s) - slumping , geology , cretaceous , sedimentary rock , impact structure , impact crater , sedimentary structures , breccia , paleontology , geochemistry , geomorphology , sedimentary depositional environment , structural basin , physics , astronomy
— The effect of shallow marine water (˜30–100 m deep) in the late excavation and early modification stages of a marine‐target crater 5 km in diameter, as exemplified by the Late Cretaceous Wetumpka impact structure in Alabama, USA, is manifest in the early collapse of a weak part of the rim. Excavation flow and connate marine water are interpreted to be factors in this collapse. This partial rim collapse catastrophically emplaced an upper‐structure‐filling unit of broken and redistributed sedimentary target formations, which presently mantles the deeper fallback breccia deposits within the structure. Furthermore, rim collapse flow facilitated the formation of a structurally modified, extrastructure terrain, which is located outside and adjacent to the collapsed rim segment. This extrastructure terrain appears to be the product of extensive slumping of poorly consolidated target sedimentary formations.