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- Title
Island arc junctions and calderas/cauldrons as the promised areas of the Quaternary gold deposits and its geological significance in the Pacific Ocean.
- Authors
Yoshihiro Kubota
- Abstract
The "island arc junctions" are the regions with plural island arcs, uplift/geanticline belts. In the Japanese Islands, the island arc junctions are situated in the three districts; the north, the central, and the south of Japan, where the Chishima (Kuril), Izu-Mariana, and Ryukyu arcs intersect the Honshu arc. There, during the Plio-Pleistocene, vast volcanic activities had repeatedly occurred and formed calderas/cauldrons with gold vein-fracture systems. Such zones are still the active volcano-geothermal areas, and earthquake activities are continuing. All of these geologic phenomena are not independent, they are mutually related. In the images of the seismic tomography, the vertical structures composed of the high and low velocity zone cut through the seismic plane, the 'subducting' lithosphere plate, which is rooted at least 100-200 km in depth. Around the depth of 20-50 km±, the low velocity lenses like a wiener or boudinage spread over 200 km or more. Shallowest low velocity spots below the surface are located directly beneath the active volcanoes. Therefore, this is considered a magma, melted layer. These geological features suggest that the island arc junctions are the intersection sites of different tectonic directions/geanticlines, that is, the deep-seated fracture zones rooted in the mantle or the outer core. The area provides a conduit for mantle energy to rise to the Earth surface - like a chimney. This mechanism isn't compatible with Plate Tectonics since Island Arcs and their junctions have to be compressional regimes associated with subduction. The locations of the island arc junctions as high potential areas of the Quaternary gold deposits in the Circum- Pacific region are pointed out on both sides of the Western and Eastern Pacific. Those sites are not only the island arc junctions in the Western Pacific but also the intersection of the submarine fracture zones/ridge and the land arcs or the areas of the bending land arcs in the Eastern Pacific. In recent years, there has been interesting discussions that gold veins are created by earthquakes and furthermore, the occurrence of earthquakes is related to the injection of "supercritical fluids". "Supercritical fluids" will be the key to this problem.
- Subjects
PACIFIC Ocean; CALDERAS; EARTHQUAKES; BOUDINAGE (Geology); SUPERCRITICAL fluids; SEISMIC tomography; EARTH'S mantle
- Publication
New Concepts in Global Tectonics Journal, 2017, Vol 5, Issue 4, p522
- ISSN
2202-5685
- Publication type
Article