English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Abundant geologic, geophysical, and paleontologic evidence from ODP drilling in the Japan Sea and from adjacent continental and insular areas demonstrates that the sea has evolved rapidly over the past 32 m.y. and is now in an early stage of compressive destruction. Stratigraphic, geochronologic, and paleobathymetric data derived from ODP Sites 794, 795, 796,797, 798, and 799, offshore exploration wells, and uplifted and deformed Neogene stratigraphic sections exposed on the Korean Peninsula and the islands of Honshu, Hokkaido, and Sakhalin were used to analyze the timing and patterns of backarc subsidence characterizing each stage in the evolution of the Japan Sea. An extensional tectonic regime and subsidence dominate backarc evolution ca. 32 Ma to 10 Ma at which time regional uplift was initiated marking the onset of a compressional regime that continues to the present. Backstripping techniques were applied to five Neogene stratigraphic columns in contrasting depositional, crustal, and tectonic settings to derive estimates of variations in rates of total and tectonically driven subsidence, presumably reflecting fundamental changes in crustal behavior during backarc evolution. The five Neogene sequences analyzed include; (1) the Pohang onshore section on the southeastern Korean Peninsula, (2) the Dolgorae-1 offshore well in the southern Tsushima Basin, (3) the Oga Peninsula onshore section in northwestern Honshu, (4) ODP Site 794 at the juncture between the Japan and Yamato basins, and (5) the southern Sakhalin onshore section representing the northern margin of the Japan Sea. Initial rifting, extension, and thermal subsidence in the Japan Sea region commenced in late Oligocene time (ca. 32-25 Ma) at rates of < 150 m/m.y. accompanied by widespread deposition of non-marine sediment and volcanic units and probable early spreading in the Japan Basin. A period of accelerating subsidence (100-500 m/m.y.), backarc spreading, rift propagation, massive basaltic magmatism, and crustal extension began in the early Miocene ca. 24-23 Ma culminating in subsidence of the Japan, Yamato, and Tsushima basins to near their present depths (2-3 km) by 20-18 Ma. Slow subsidence persisted from 18 Ma to 16-15 Ma when a second episode of rapid subsidence occurred as rifts propagated into the arc, arc-flanks, and other areas of weakened continental crust around the perimeter of the sea creating numerous sub-basins accompanied by middle Miocene rotation of southwest Japan and a second pulse of basaltic magmatism. Maximum rates of tectonic subsidence during middle Miocene sub-basin formation exceeded 900 m/m.y. pointing to a pull-apart origin for these features which were initially sediment-starved and filled with pelagic and hemipelagic diatomaceous muds. Relatively low rates of subsidence (<200 m/m.y.) characterize the tectonically quiescent middle-late Miocene stage in the evolution of the sea from 12.5 to 10 Ma. Evidence of initial regional uplift (10-100 m/m.y.) appears in the southern Japan Sea ca. 11-10 Ma with compressional uplift and destruction of Miocene sub-basins in arc and arc-flank areas of Honshu, Hokkaido, and Sakhalin ca. 5 Ma. Rates of uplift subsequently accelerated to 500-1500 m/m.y. in late Pliocene and Pleistocene time (2.0-0.7 Ma) resulting in widespread deformation of pre-upper Pleistocene sedimentary sequences and the tectonic reorganization of the eastern, central, and southern Japan Sea creating the borderland-style topography now characterizing these areas.

Subsidence of the Japan Sea: Stratigraphic Evidence from ODP Sites and Onshore Sections