Open AccessCOCORP: new perspectives on the deep crust
Author(s) -
Brown L.,
Wille D.,
Zheng L.,
DeVoogd B.,
Mayer J.,
Hearn T.,
Sanford W.,
Caruso C.,
Zhu T.F.,
Nelson D.,
Potter C.,
Hauser E.,
Klemperer S.,
Kaufman S.,
Oliver J.
Publication year - 1987
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1987.tb04386.x
Subject(s) - geology , crust , seismology , tectonics , magmatism , magma , fibrous joint , layering , petrology , volcano , paleontology , medicine , botany , anatomy , biology
Summary. Relict sutures from colliding continents, regions characterized by a “young” Mono, layering and faulting throughout the crust, mid‐crustal magma traps, and seismic “bright spots” which suggest deep crustal fluids are among recent COCORP findings. In addition, new studies of signal penetration, noise mitigation, recording geometry, and coherency filtering have yielded better understanding of, and substantial improvements in, data quality. Amplitude anomalies, or “bright spots”, in the Basin and Range may be due to magma at mid‐crustal levels; in one case, a normal fault appears to link the deep magma with young surface volcanics. Another bright spot. 15 km deep in southeastern Georgia, has a flat geometry that suggests a gas/liquid interface, perhaps within fluids underthrust along an Appalachian suture. The Mono continues to appear relatively undisturbed in many regions of past deformation, suggesting that its formation post‐dates these major tectonic episodes. The diversity of reflection patterns from the U.S. Cordillera casts further doubt on the generality of the common model of a reflective, layered lower crust underlying a transparent upper crust.