Autostratigraphic norm to delta-shelf sedimentary systems growing with multiple sea-level cycles

2015 Fiscal Year Final Research Report

• Project/Area Number: 25400489
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Geology
• Research Institution: Nagasaki University
• Principal Investigator: MUTO Tetsuji 長崎大学, 水産・環境科学総合研究科(環境), 教授 (70212248)
• Co-Investigator(Renkei-kenkyūsha): SEKIGUCHI Tomohiro 筑波大学, 生命環境科学研究科, 講師 (90400647) ; SATO Tomoyuki 独立行政法人産業技術総合研究所, 地質情報研究部門, 研究員 (80555152)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 大陸棚 / オート層序学 / 非平衡応答 / デルタ / 沖積河川 / 分流チャネル / 水深 / 海水準変動

Outline of Final Research Achievements

An autostratigraphic framework of deltaic continental shelves that evolve with multiple sea level cycles is suggested by means of tank experiments and geometrical modeling. The framework predicts that the resulting stratigraphic architecture can have a distinct stable pattern reflecting a progressively-converging non-equilibrium response of the depositional system to the sea level forcing. The basinward expansion of a deltaic continental shelf during a rising period leads to earlier realization of non-deltaic transgression which is accompanied by the generation of non-depositional shelf surface. During sea level fall, the alluvial topset river of the prograding delta tends to attain a graded sate in an earlier stage. Thus, as a continental shelf grows with multiple sea level cycles, a distinct, stable stratigraphic pattern that is composed only of non-deltaic transgressive deposits and progradational deltaic lobes fed by a graded alluvial river will be built eventually.

Free Research Field

堆積地質学