Abstract The Gippsland Basin contains some of the largest hydrocarbon accumulations in Australia, and has been in production since the 1920's. These hydrocarbons are trapped by large growth anticlines offshore, in reservoirs of the Cretaceous to Eocene-aged Latrobe Group. Despite the obvious importance of these growth anticlines, the timing of their formation, and the overall Cenozoic tectonic history of the basin is not well understood. Here, we present a detailed growth strata analysis of the faults and anticlines within the Cenozoic sediments of the Gippsland Basin. This indicates two major phases of tectonism in the basin: 1. Late Cretaceous to Eocene extension, and 2. Oligocene to Holocene compression. Detailed analysis of the extensional phase indicates the development of numerous normal growth faults, which display an overall reduction in the magnitude of extension from the Late Cretaceous to the Eocene, commonly terminating at the top of the Latrobe Group. The shift to compressional tectonism occurred at approximately the Eocene-Oligocene boundary (~34 Ma). A major and widespread episode of compression then occurred, with evidence of growth on anticlines and reverse faults beginning in the early Oligocene. This previously unrecognized early Oligocene event produced significant growth (20–50% total growth) of the major anticlines which host hydrocarbon accumulations. The early Oligocene event represents the first phase of the compressional tectonic regime that continues to the present day in SE Australia. It appears likely that this Oligocene event affected other basins in SE Australia and probably contributed to uplift of the Eastern Highlands. The underlying tectonic cause for this Oligocene compressional regime is enigmatic and may be related to far field tectonic processes. A second pulse of compressional tectonism and anticline growth occurred during the mid-Miocene and is generally more significant in the onshore regions of the basin. The youngest phase of compressional tectonism beginning in the Late Miocene (~10 Ma) is also more intense in onshore regions and is marked by an unconformity that is widespread in SE Australia.

中文翻译：

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吉普斯兰盆地的新生代构造历史：澳大利亚东南部挤压构造的早渐新世开始

摘要 Gippsland 盆地包含澳大利亚一些最大的油气藏，自 1920 年代以来一直在生产。这些碳氢化合物被近海大型生长背斜捕获，位于白垩纪至始新世拉特罗布群的储层中。尽管这些生长背斜的重要性显而易见，但它们形成的时间以及盆地的整体新生代构造历史尚不清楚。在这里，我们对吉普斯兰盆地新生代沉积物中的断层和背斜进行了详细的生长地层分析。这表明盆地构造作用的两个主要阶段：1. 晚白垩世至始新世的伸展，以及 2. 渐新世至全新世的压缩。对伸展阶段的详细分析表明许多正常生长断层的发展，其显示从晚白垩世到始新世的延伸幅度总体减小，通常终止于拉特罗布群的顶部。向挤压构造运动的转变发生在大约始新世-渐新世边界（~34 Ma）。随后发生了一次重大而广泛的压缩事件，有证据表明在渐新世早期开始的背斜和逆断层上有生长。这种先前未被认识的渐新世早期事件导致承载油气聚集的主要背斜显着增长（总增长 20-50%）。渐新世早期事件代表了澳大利亚东南部持续至今的挤压构造体制的第一阶段。似乎这个渐新世事件影响了澳大利亚东南部的其他盆地，并可能促成了东部高地的隆起。这种渐新世挤压体制的潜在构造原因是神秘的，可能与远场构造过程有关。第二次挤压构造运动和背斜生长发生在中新世中期，通常在盆地陆上地区更为显着。在中新世晚期（~10 Ma）开始的最年轻的挤压构造作用阶段在陆上地区也更加强烈，并且以澳大利亚东南部普遍存在的不整合面为特征。第二次挤压构造运动和背斜生长发生在中新世中期，通常在盆地陆上地区更为显着。在中新世晚期（~10 Ma）开始的最年轻的挤压构造作用阶段在陆上地区也更加强烈，并且以澳大利亚东南部普遍存在的不整合面为特征。第二次挤压构造运动和背斜生长发生在中新世中期，通常在盆地陆上地区更为显着。在中新世晚期（~10 Ma）开始的最年轻的挤压构造作用阶段在陆上地区也更加强烈，并且以澳大利亚东南部普遍存在的不整合面为特征。