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THE JAPAN BASIN ‐ A TECTONIC TROUGH
Author(s) -
Choi Dong Ryong
Publication year - 1984
Publication title -
journal of petroleum geology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.725
H-Index - 42
eISSN - 1747-5457
pISSN - 0141-6421
DOI - 10.1111/j.1747-5457.1984.tb00888.x
Subject(s) - geology , tectonics , trough (economics) , crust , oceanic crust , structural basin , continental crust , precambrian , fault (geology) , paleontology , seismology , plate tectonics , basement , geophysics , subduction , economics , macroeconomics , civil engineering , engineering
An integrated analysis of the currently available geological and geophysical data in and around the Japan Sea indices that the JapanBasin originated as a tectonic trough developed in an area of continental crust, a NE extension of the PreCambrian Ogcheon Trough on the Korean Peninsula. This conlusion is based on the following evidence: (1) tectonic trends recognized on the surrounding continents are basically traceable over the entire Japan Sea area; (2) the “sub‐oceanic” (“basaltic”) crust replaces all pre‐existing structures without conspicous horizontal displacement; (3) detailed submarine geologic maps show the predominance of vertical tectonics, which were controlled primarilyby makor‐deep seated fault systems coincide with linear magnetic anomalies and high heat‐flow zones, and are loci of volcanic activities; and (5) comparisonof geological and seismic data proves that the acoustic basement in the Japan Basin is provided bythe Paleozoic marine sediments, and not the “basaltic” layer as has hitherto been considered by many geoscientists. The above geological evidence conflicts with the plate‐tectonics or spreasing‐originhypotheses proposed by many authors. The linear magnetic anomalies generally coincide awithmajor fault zones and appear to show primary fracture patterns of the crust which interacted awith the upper mantle. Therefore, the validity of the linear magnetic anomalies as a criterion for determining spreading centres and rates is quesioned. The large discrepancy in structuralinterpertations derived, on the one hand, from a gephysical approach to the Japan Basin, and, on the other hand, from a geophysical approach, leads us to question whether the identification of continental and oceanic crust based on seismic refraaction data is valid. All the experience we have had in the controversy over the origin of the Japan Sea teaches us the following impotant lessons: (1) geological and geophsical studies need to be intergrated; and (2) detailed geological studies, especially geologic mapping of the continental shelf, the borderland, and submarine rises in close association with the mapped land geology, need to procede the discussion of any hypothesis.