Gilbert-type deltas recording short-term base-level changes: Delta-brink morphodynamics and related foreset facies

被引:74
|
作者
Gobo, Katarina [1 ]
Ghinassi, Massimiliano [2 ]
Nemec, Wojciech [1 ]
机构
[1] Univ Bergen, Dept Earth Sci, N-5007 Bergen, Norway
[2] Univ Padua, Dept Geosci, I-35131 Padua, Italy
关键词
Base-level changes; debrites; delta morphodynamics; delta-slope processes; sea-level changes; turbidites; BAJA-CALIFORNIA-SUR; PLIOCENE LORETO BASIN; FAN-DELTA; SEQUENCE STRATIGRAPHY; CORINTH RIFT; DEPOSITIONAL PROCESSES; POSTGLACIAL COLLUVIUM; SEDIMENTARY FACIES; BETIC CORDILLERA; WESTERN NORWAY;
D O I
10.1111/sed.12212
中图分类号
P5 [地质学];
学科分类号
0709 ; 081803 ;
摘要
Gilbert-type deltas are sensitive recorders of short-term base-level changes, but the delta-front record of a base-level rise tends to be erased by fluvial erosion during a subsequent base-level fall, which renders the bulk record of base-level changes difficult to decipher from the delta-front deposits. The present detailed study of three large Pleistocene Gilbert-type deltas uplifted on the southern coast of the Gulf of Corinth, Greece, indicates a genetic link between the delta-front morphodynamic responses to base-level changes and the delta-slope sedimentation processes. Sigmoidal delta-brink architecture signifies a base-level rise and is accompanied by a debrite-dominated assemblage of delta foreset deposits, thought to form when the aggrading delta front stores sediment and undergoes discrete gravitational collapses. Oblique delta-brink architecture tends to be accompanied by a turbidite-dominated assemblage of foreset deposits, which are thought to form when the delta-front accommodation decreases and the sediment carried by hyperpycnal effluent bypasses the front. This primary signal of the system response to base-level changes combines further with the secondary noise' of delta autogenic variation and possible allogenic fluctuations in fluvial discharge due to regional climatic conditions. Nevertheless, the evidence suggests that the facies trends of delta foreset deposits may be used to decipher the delta hidden' record of base-level changes obliterated by fluvial topset erosion. Early-stage bayhead deltas may be an exception from the hypothetical model, because their narrow front tends to be swept by river floods irrespective of base-level behaviour and their subaqueous slope deposits are thus mainly turbidites.
引用
收藏
页码:1923 / 1949
页数:27
相关论文
共 3 条
  • [1] RECIPROCAL CHANGES IN FORESET TO BOTTOMSET FACIES IN A GILBERT-TYPE DELTA: RESPONSE TO SHORT-TERM CHANGES IN BASE LEVEL
    Gobo, Katarina
    Ghinassi, Massimiliano
    Nemec, Wojciech
    JOURNAL OF SEDIMENTARY RESEARCH, 2014, 84 (11) : 1079 - 1095
  • [2] Sedimentary facies related to supercritical-flow bedforms in foreset slopes of a Gilbert-type delta (middle Pleistocene, central Japan)
    Okazaki, Hiroko
    Isaji, Shinji
    Kurozumi, Taiji
    SEDIMENTARY GEOLOGY, 2020, 399
  • [3] Sedimentary evolution and structure types of short-term base-level cycle sequences of shallow lacustrine fluvial-dominated delta: Example of Fuyu oil layer in southern Fuxin uplift of Songliao Basin
    Sun, Yu
    Ma, Shi-Zhong
    Yan, Bai-Quan
    Zhao, Hui
    Yu, Li-Ming
    Cong, Lin
    Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology), 2013, 44 (08): : 3405 - 3414