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Sedimentary facies distribution of the upper Cenozoic fourth-order depositional sequences and basin-fill process of the Niigata back-arc sedimentary basin, central Japan

Conference ·
OSTI ID:425389
 [1];  [2]
  1. Teikoku Oil Co. Ltd., Tokyo (Japan)
  2. Shinshu Univ., Matsumoto (Japan)

The Niigata back-arc basin, compartmentarized and characterized by steep slope, large sediment influx related to active island-arc and extremely large depositional rate higher than 200 cm/1,000 year, had been formed at a stroke with close relationship to Japan Sea opening in the Middle Miocene age. A large part of this basin has been filled with a thick 2nd-order tectono- sequence by present. Deposition of 3rd-order depositional sequences comprising 2nd-order tectono-sequence is interpreted to correspond with filling-up of subbasins. A lower 3rd-order depositional sequence distributes rather proximal part of the Niigata basin, and an upper one occupies distal part. Stacking pattern of the 3rd-order depositional sequences, therefore, demonstrates a large scale progradational configuration. Their component 4th-order depositional sequences, ranging several tens through hundreds meter in thickness, are suitably recognized on a set of seismic profiles. Those 4th-order depositional sequences consist of depositional systems like fan-delta, fluvial, delta, shelf, slope and basin floor on the basis of assemblages of the observed sedimentary facies and facies associations in many exploratory wells. Sedimentary facies distributions, as a conclusion, are interpreted to reflect faithfully 4th-order relative sea-level cycles in sedimentary basins in the active margin area like the Niigata back-arc sedimentary basin. 3rd-order sequences, composed of those 4th-order sequences, fill subbasins progressively from proximal one to distal. In addition, process of basin evolution would correspond to 2nd-order tectonic event in the active margin basins.

OSTI ID:
425389
Report Number(s):
CONF-960527--
Country of Publication:
United States
Language:
English