Climate and sea‐level controlling internal architecture of a Quaternary carbonate ramp (Northwest Shelf of Australia)
Climate and sea‐level controlling internal architecture of a Quaternary carbonate ramp (Northwest Shelf of Australia)
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DOI：
10.1111/sed.12948
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发表时间：
2021-10
期刊：
影响因子：
3.5
通讯作者：
Maximilian Hallenberger;L. Reuning;S. Back;S. Gallagher;H. Iwatani;K. Lindhorst
中科院分区：
文献类型：
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作者：
Maximilian Hallenberger;L. Reuning;S. Back;S. Gallagher;H. Iwatani;K. Lindhorst
澳大利亚西北部的大陆架有一个广泛的热带碳酸盐斜坡，形成了一个重要的模板，用于解释沉积记录中的类似系统。然而，很少有人知道它的发展，从中到晚第四纪，一个时期的高频率冰川海平面和气候变化。本研究描述了西北大陆架中斜坡至外斜坡断面的岩心和地震反射数据。核心材料包括国际海洋发现计划遗址U1461（356号探险队）的上部70米，覆盖了过去的500 kyr。在干旱的冰川期，沉积的特征是无机沉淀的碳酸盐，包括文石针泥和卵。在浅海条件下，在小型平顶平台上发育了鲕粒。地震和沉积学证据表明，这些平台在现今的中斜坡顶部局部发展，并且通常仅在单一冰期期间活动。文石-针状泥沉淀（无机）在浅水区。这些细沉积物中的大部分随后被输出到更深的水中，在那里它们与远洋碳酸盐混合。潮湿的间冰期一般以澳大利亚西北大陆架的沉积减少为特征，导致冰川低位沉积物的合并。然而，大量的骨架碳酸盐沉积在研究的位置在全新世和海洋同位素阶段11。这些沉积物的积累被解释为一个当地的特点所造成的下降，目前的能源。该研究强调了一个斜坡系统，在控制碳酸盐沉积方面，气候与海平面一样重要。
The continental shelf of Northwest Australia hosts an extensive tropical carbonate ramp that forms an important template for the interpretation of similar systems in the sedimentary record. Yet, little is known about its development from the middle to late Quaternary, a period of high frequency glacioeustatic changes in sea‐level and climate. This research describes core and seismic‐reflection data from a mid‐ramp to outer ramp transect at the Northwest Shelf. Core material includes the upper 70 m of International Ocean Discovery Program Site U1461 (Expedition 356), which covers the last 500 kyr. During arid glacials, sedimentation is characterized by inorganically precipitated carbonates, including aragonite‐needle mud and ooids. Ooids developed under shallow marine conditions on small‐scale flat‐topped platforms. Seismic and sedimentological evidence indicates that these platforms developed locally on top of the present‐day mid‐ramp and were typically only active during a single glacial period. Aragonite‐needle mud precipitated (inorganically) in shallow‐water areas. Much of these fine sediments were subsequently exported into deeper water where they mixed with pelagic carbonates. Humid interglacials are generally characterized by reduced sedimentation across the Northwest Shelf of Australia, resulting in the amalgamation of glacial lowstand deposits. Yet, substantial amounts of skeletal carbonates were deposited at the studied location during the Holocene and Marine Isotope Stage 11. These sediment accumulations are interpreted as a local feature caused by a decline in current energy. The study presented highlights a ramp system where climate is as important as sea‐level in controlling carbonate deposition.