Science Links Japan | Reconstruction of the delta and estuary systems and sequence stratigraphy of the Plio-Peistocene strata in the Higashikubiki Hills, Niigata Prefecture, central Japan.

Reconstruction of the delta and estuary systems and sequence stratigraphy of the Plio-Peistocene strata in the Higashikubiki Hills, Niigata Prefecture, central Japan.

Accession number;01A0132583

Title;Reconstruction of the delta and estuary systems and sequence stratigraphy of the Plio-Peistocene strata in the Higashikubiki Hills, Niigata Prefecture, central Japan.

Author; HOYANAGI KOICHI (Shinshu Univ., Fac. of Sci.) IKEZU DAISUKE (Higashinihonryokakutetsudo Naganoshisha) SHIMIZU YUKA (Bukkusenta Nagaoka) OMURA AKIKO (Shinshudai Daigakuinkogakukeikenkyuka)

Journal Title;Earth Science

Journal Code:F0193A

ISSN:0366-6611

VOL.54;NO.6;PAGE.393-404(2000)

Figure&Table&Reference;FIG.9, REF.43

Pub. Country;Japan

Language;Japanese

Abstract;The study area is located in the northern part of Higashikubiki Hills in the Niigata Prefecture, central Japan. The studied area is underlain by the Plio-Pleistocene Uonuma Group and Haizume Formation, covers the Yamaya Anticline. The Haizume Formation, which is equivalent to the Middle Uonuma Formation, distributed only on the western wing. The Uonuma Group is represented by two types of depositional cycles. One shows shallowing upward successions deposited on shelf to shoreface environments of wave-dominated delta system and is accompanied with transgressive lag at the base. The other shows repetition of fluvial-estuary sediments. Depositional systems of the Uonuma Group changed from delta to estuary in the early Pleistocene. The Haizume Formation consists of shallowing upward successions, which resulted from deposition in margin of the wave-dominated delta system. Correlation of the ash layers indicates deposition of the Haizume Formation occurred as a continuation from the delta system when the systems changed in the Uonuma Group. The sequence stratigraphic analysis has revealed seven depositional sequences in the Uonuma Group and the Haizume Formation. Each sequence has a duration of 0.14My on average. These fourth-order depositional sequences are correlative with those of the other areas in Niigata Sedimentary Basin. The fourth-order sequence boundaries were formed concurrently with the periods of fourth-order sea-level fall in the oxygen isotope curve. (author abst.)

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