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Basinward transport of Chicxulub ejecta by tsunami-induced backflow, La Popa basin, northeastern Mexico, and its implications for distribution of impact-related deposits flanking the Gulf of Mexico
被引:36
|作者:
Lawton, TF
[1
]
Shipley, KW
Aschoff, JL
Giles, KA
Vega, FJ
机构:
[1] New Mexico State Univ, Inst Tecton Studies, Las Cruces, NM 88003 USA
[2] Univ Nacl Autonoma Mexico, Inst Geol, Coyoacan 04510, DF, Mexico
来源:
关键词:
Chicxulub crater;
ejecta;
tsunami;
Cretaceous-Tertiary boundary;
Mexico;
D O I:
10.1130/G21057.1
中图分类号:
P5 [地质学];
学科分类号:
0709 ;
081803 ;
摘要:
Ejecta-bearing strata are present at the top of Cretaceous foreland-basin deposits throughout the La Popa basin in northeastern Mexico. In the southeast part of the basin, locally thick (as much as 4.6 m) ejecta-rich conglomeratic strata occupy valley-like features at a bathymetric break that separated Maastrichtian upper shoreface from lower shoreface and prodelta depositional settings. Clast-supported textures, normally graded planar conglomerate-sandstone couplets, upcurrent-dipping low-angle cross-laminae, sparse paleocurrent data, and transported fossils indicate deposition by south- to southeast-directed turbulent, supercritical How. In the northwest part of the basin, ejecta grains are present but less common in correlative deposits. Sediment, ejecta, and organisms were eroded from shoreward environments and transported basinward by backflow of run-up surge(s) emplaced against the continent by one or several tsunami(s). High-discharge, supercritical offshore-directed flow provides a mechanism for transport of voluminous, ejecta-bearing sediment and late Maastrichtian marine organisms into deep-water Gulf of Mexico settings.
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页码:81 / 84
页数:4
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