Volcanic influences in a storm‐ and tide‐dominated shallow marine depositional system: The late permian broughton formation, southern Sydney Basin, Kiama, NSW
作者:
StuartW. Bull,
R.A.F. Cas,
期刊:
Australian Journal of Earth Sciences
(Taylor Available online 1989)
卷期:
Volume 36,
issue 4
页码: 569-584
ISSN:0812-0099
年代: 1989
DOI:10.1080/08120098908729510
出版商: Taylor & Francis Group
关键词: Broughton Formation;lavas;storm‐tide shelf sedimentation;volcaniclastic sediments
数据来源: Taylor
摘要:
Shallow marine sediments of the Broughton Formation are dominated by immature volcanic debris of intermediate to basic composition, generated in an adjacent subaerial environment by volcanism responsible for the nine shoshonite units intercalated within sediments of the Kiama region. Sediment was supplied to the offshore environment via periodic storm‐generated, expanded high density turbidity currents. Initial deposition, represented by the Westley Park Sandstone Member, was below storm wave base, during which time the depositional surface was subjected to post‐depositional tractional reworking by northerly directed, tidally influenced bottom currents. The resulting positive‐relief sand bodies on the seafloor contain tractional sedimentary structures (the ‘tractional facies association'). Areas of the substrate between these sand bodies retained their turbidite bedding structure (the ‘rhythmically bedded facies association') but were extensively bioturbated by a diverse deposit‐feeding biomass.
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