Abstract We present fossil benthic foraminiferal assemblage data from marine sediment core SS02/06-GC2 located in the abyssal plain of the Murray Canyon Group (offshore South Australia). The sedimentological characteristics indicate the presence of turbidite deposits showing classical Bouma-like sequences, dated between ~40 and 12 cal ka BP. These results confirm the previous interpretation of the observed large deep-water holes in the abyssal area where the core was sampled as being gouged by surges of high-energy turbidity currents. The presence of good indicator taxa and unique assemblages occupying specific bathymetric depths allows the determination of the source origin of the sediments making the turbidites. Three distinct faunal groups are found: 1) mostly shelf species, 2) mostly bathyal species and 3) mostly abyssal species. In the sediment core, these groups present a quasi-systematic succession, with nearly all Bouma-like sequences starting with the dominance of bathyal species in the coarse-grained base, followed by the dominance of shallow species in the silty part, and finally with abyssal species in the clays. To explain such phenomena, turbidites triggered by mixed hyperpycnal/hypopycnal flow processes and turbidity currents during periods of river floods are considered for the first time within the Murray Canyon Group. They are mostly related to periods of increased fluvial discharges during wet phases in the Murray-Darling Basin.

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从“源到汇”——从底栖有孔虫群落看墨累峡谷群过去动态的新视角

摘要 我们展示了位于墨累峡谷群（南澳大利亚近海）深海平原的海洋沉积物核心 SS02/06-GC2 的底栖有孔虫化石组合数据。沉积学特征表明存在浊积岩沉积，显示出经典的类似 Bouma 的序列，年代在 ~40 和 12 cal ka BP 之间。这些结果证实了先前对深海区域中观察到的大型深水孔的解释，在该区域对岩心进行采样，因为它被高能浑浊流的浪涌凿开。良好的指示类群和占据特定测深深度的独特组合的存在允许确定制造浊积岩的沉积物的来源。发现了三个不同的动物群：1) 主要是陆架物种，2) 主要是深海物种和 3) 主要是深海物种。在沉积岩心中，这些类群呈现出准系统演替，几乎所有类波马层序均以粗粒基底深海种为主，粉质部浅层种占优势，最后为粘土中的深海物种。为了解释这种现象，在墨累峡谷群中首次考虑了在河流洪水期间由混合高密度/低密度流动过程和浊流引发的浊流。它们主要与墨累-达令盆地潮湿阶段的河流流量增加有关。其次是粉质部分浅层物种的优势，最后是粘土中的深海物种。为了解释这种现象，在墨累峡谷群中首次考虑了在河流洪水期间由混合高密度/低密度流动过程和浊流引发的浊流。它们主要与墨累-达令盆地潮湿阶段的河流流量增加有关。其次是粉质部分浅层物种的优势，最后是粘土中的深海物种。为了解释这种现象，在墨累峡谷群中首次考虑了在河流洪水期间由混合高密度/低密度流动过程和浊流引发的浊流。它们主要与墨累-达令盆地潮湿阶段的河流流量增加有关。