Low‐temperature thermochronology (LTT) is commonly used to investigate onshore records of continental rifting and geomorphic evolution of passive continental margins. The SE Australian passive margin, like many others, has an elevated plateau separated from the coastal plain by an erosional escarpment, presumed to originate through Cretaceous rifting prior to Tasman Sea seafloor spreading. Previous LTT studies have focused on reconciling thermal histories with development of the present‐day topography. New apatite LTT data along an escarpment‐to‐coast transect define a classic “boomerang” (mean track length vs. fission‐track age), indicating variable overprinting of late‐Palaeozoic cooling ages by a younger, mid‐Cretaceous cooling event. Regionally, however, the boomerang trend diverges NNW away from the coast and crosses the escarpment, implying the underlying thermal history pre‐dates escarpment formation and is largely independent from post‐breakup landscape evolution. We suggest that Cretaceous cooling might relate to erosion of Permo‐Triassic sedimentary cover from a formerly more extensive Sydney Basin.

中文翻译：

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重新审视冈比亚瓦纳解体后澳大利亚东南部裂谷边缘的演变

低温热年代学（LTT）通常用于调查陆上裂谷和被动大陆边缘地貌演化的陆上记录。与其他许多地区一样，澳大利亚东南部的被动边缘也有一个高原，由侵蚀性的悬崖与沿海平原隔开，推测是由塔斯曼海底海底扩张之前的白垩纪裂谷引起的。以前的LTT研究专注于使热历史与当今地形的发展保持一致。沿悬崖到海岸断面的新磷灰石LTT数据定义了一个经典的“飞旋镖”（平均轨道长度与裂变轨道年龄），表明晚白垩世冷却年龄的变化叠印是由年轻的白垩纪中期冷却事件引起的。然而，就区域而言，回旋镖趋势使NNW偏离了海岸，并跨越了悬崖，暗示潜在的热史早于断层形成之前，并且在很大程度上与解体后的景观演化无关。我们认为白垩纪的冷却可能与以前更广泛的悉尼盆地的二叠系-三叠纪沉积覆盖层的侵蚀有关。