Age Estimation of the Japan Sea on the Basis of Stratigraphy, Basement Depth, and Heat Flow Data

Tamaki, Kensaku

doi:10.5636/jgg.38.427

Cited by 74 publications

(96 citation statements)

References 17 publications

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“…Both measurements are within the error of measurement of the mean for the Yamato Basin average (Tamaki, 1986). A line of seafloor stations roughly along the line of seamounts that lie near the central axis of the Yamato Basin yielded heatflow values that are lower on average and more variable.…”

Section: Temperature Measurementsmentioning

confidence: 53%

“…Heat flow is consistently about 10 mW/m 2 higher in this part of the Yamato Basin than it is over the Kita-Oki Bank and the Yamato Rise. The average value in this part of the basin is 87 mW/m 2 vs. 76 mW/m 2 for the bank areas; both are less than the average heat-flow value for the Yamato Basin (97 ± 12 mW/m 2 ; Tamaki, 1986). The heat-flow value measured nearest to Site 797 is 102 mW/m 2 .…”

Section: Heat Flowmentioning

confidence: 90%

“…The rocks consist of Mesozoic granitic rocks and upper Oligoceneupper Miocene volcanic rocks. Summaries of published ages of dredged materials from the Yamato Rise can be found in Kaneoka (1986), Tamaki (1988), Kaneoka et al (1988, in press), and Kaneoka and Yuasa (1988). These results should be used cautiously, as the rocks are typically somewhat altered.…”

Section: Basement Rocksmentioning

confidence: 99%

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Site 797

1990

Proceedings of the Ocean Drilling Program

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1 Tamaki, K., Pisciotto, K., Allan, J., et al., 1990. Proc. ODP, Init. Repts., 127: College Station, TX (Ocean Drilling Program). Principal results: The objectives at Site 797, located in the southern Yamato Basin, were (1) to determine the age and nature of acoustic basement, (2) to measure the direction and magnitude of the present stress field, and (3) to characterize the sedimentation, subsidence, and oceanographic evolution of the area. The results at Site 797 are summarized below and in Figure 1. The principal results at Site 797 are as follows:1. Acoustic basement and an overlying seismic interval at this site comprise basalts and dolerites and interlayered volcaniclastic sandstones, siltstones, and silty claystones. The age of the sediments which overlie the shallowest basalt layer is estimated to be about 19 Ma. Based on paleodepth estimates using microfossils within these sediments and the sedimentologic interpretation of the underlying volcaniclastic sediments, this part of the Yamato Basin probably subsided rapidly during the early Miocene. The uppermost basalts most likely represent submarine lava flows, whereas the bulk of the underlying igneous units are sills and dikes. The upper nine units are high-Al basalt in composition, consistent with generation during the early stages of arc rifting. However, the units below these are mildly alkaline basalts and enriched tholeiites, which are unrelated to the overlying basalts and were probably derived from a different mantle source.2. The in-situ stress field could not be determined, because poor hole conditions precluded packer/hydro fracture tests. A borehole televiewer log over one basalt interval showed fractures but no borehole breakouts for stress directions.3. The lithologic and paleontological data indicate at least four principal stages in the evolution of this part of the Yamato Basin: (a) an early Miocene period of submarine basaltic volcanism and concomitant deposition of gravity-flow and current-reworked volcani- 323 SITE 797clastic sandstones and siltstones on a shelf or slope, probably outboard of a delta; (b) a late early to early middle Miocene phase of diminishing submarine volcanic activity, warm surface waters, and deposition of calcareous and slightly phosphatic hemipelagic claystones at lower middle bathyal depths (1500-2000 m) in a poorly oxygenated basin; (c) a late Miocene to late Pliocene cooling period beginning with an interval of anomalously slow sedimentation (5 m/m.y.) or a hiatus and characterized by dominant but variable diatomaceous sedimentation at lower middle bathyal depths (1500-2000 m); and (d) a latest Pliocene to Holocene stage during which diatomaceous sedimentation diminished volcanic-ash production and terrigenous input increased, subsidence continued, and climate oscillated to produce a sequence of interlayered light-and dark-colored silty clays having variable organic-carbon contents. In contrast with the more northern sites drilled during Leg 127, the sediments at Site 797 contain more carbonate suggesting ...

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Section: Temperature Measurementsmentioning

confidence: 53%

Section: Heat Flowmentioning

confidence: 90%

Section: Basement Rocksmentioning

confidence: 99%

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Site 797

1990

Proceedings of the Ocean Drilling Program

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“…There have been many arguments when and how the back-arc opening occurred behind the Japanese Islands (Otofuji et al, 1985;Tamaki, 1986Tamaki, , 1988. Recent studies on Cenozoic stratig raphy of the Japanese Islands , 40Ar -39Ar dating of submarine volcanic rocks from the Japan Sea (Kaneoka et al, 1990(Kaneoka et al, , 1992, and results of Ocean Drilling Project (Jolivet and Tamaki, 1992) The outline of geology of Oki-Dogo Island (Fig.…”

Section: Tectonic Settingmentioning

confidence: 99%

Geochronology of alkali volcanism in Oki-Dogo Island, Southwest Japan: Geochemical evolution of basalts related to the opening of the Japan Sea.

et al. 1994

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“…To clarify the formation processes of a back-arc basin, their time sequence is an important factor. Although the time of formation of the Japan Sea has been discussed over many years by many investigators (e.g., Okamura, 1927;Isezaki, 1986;Tamaki, 1986), no definite consensus has been obtained yet. The estimated ages range from more than 30 Ma to about 10 Ma.…”

Section: Introductionmentioning

confidence: 99%