Journal article

Origin and timing of the Miocene-Pliocene unconformity in southeast Australia

JA Dickinson, MW Wallace, GR Holdgate, SJ Gallagher, L Thomas

JOURNAL OF SEDIMENTARY RESEARCH | SEPM-SOC SEDIMENTARY GEOLOGY | Published : 2002

Abstract

An unconformity is present close to the Miocene-Pliocene boundary in the onshore and nearshore portions of the Otway, Port Phillip-Torquay, and Gippsland basins of southeast Australia. The unconformity is angular (generally < 1-5° angularity), with the under-lying Miocene units having been deformed (gentle folding and reverse faulting) and eroded prior to deposition of the Pliocene succession. The unconformity also marks a change from Oligocene-Miocene deposition of cool-water carbonate sediments and brown coal-bearing successions to the accumulation of more siliciclastic-rich sediments in Pliocene time. The Miocene-Pliocene boundary therefore represents an interval of significant regional u..

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