High-frequency temporal variability of provenance signal in the submarine fan with the narrow shelf: Insights from sediment delivery and formation of late Triassic Zhuoni fan in the northeastern Paleo-Tethys Ocean
High-frequency temporal variability of provenance signal in the submarine fan with the narrow shelf: Insights from sediment delivery and formation of late Triassic Zhuoni fan in the northeastern Paleo-Tethys Ocean
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DOI：
10.1111/bre.12835
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发表时间：
2023-11-30
期刊：
影响因子：
3.2
通讯作者：
Zhang，Chengcheng
中科院分区：
文献类型：
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作者：
Tan，Mingxuan;Sun，Haonan;Zhang，Chengcheng
具有狭窄大陆架的海底扇通常对环境信号传播有反应;然而，几种同种异体强迫可能会使源到汇功能进一步复杂化。在此，我们主要基于西秦岭潘源剖面的过程沉积学和物源研究，记录了古特提斯洋东北部发育的晚三叠世卓尼扇中记录的高频物源变化和不同的沉积物输送模式。青藏高原东北缘。高密度、低密度浊积岩、混合事件层和超稠岩分布于以瓣状为主的海底扇序列中。周围露头的野外沉积学证据表明，陆棚边缘破坏是大多数高密度和低密度浊积岩的主要原因，总体上没有海底滑坡或滑塌，而狭窄的陆棚配置以及晚三叠世的潮湿脉冲有利于卓尼扇中洪水相关的超稠岩的出现。碎屑锆石颗粒（N= 6;n= 123-272）通常具有古生代-中生代的年龄（约100年）。350-250 Ma和500-400 Ma）和新太古代-古元古代年龄（约。2100-1750 Ma和2600-2400 Ma），但由于前寒武纪年龄人口的比例不同，可进一步划分为三个年龄组。研究结果表明，南、北秦岭造山带、祁连造山带、华北造山带各段以及秦岭与祁连造山带的构造交接区可能是潜在的源区。碎屑锆石年龄谱和重矿物组合所反映的物源信号的时间变化表明这些来源对海平面波动的不同贡献。因此，尽管卓尼扇总体上是狭窄的陆架，但它可能会引起卓尼扇反应性和缓冲性源汇沉积物输送模型之间的时间变化。卓尼低位扇的发育与河口的盆外高密度输送直接相关，其高频物源变率记录了通过陆上集水区的不同信号传递效率，并对时间存储、河流再生甚至区域气候变率产生显著影响。高水位海底扇被认为是由陆架边缘破坏和陆架区沉积物缓冲形成的，这与强烈的物源混合有关。我们的工作提供了一个新的视角来破译深水沉积物输送的不同起源，以应对高频海平面和气候变化。
The submarine fan with a narrow shelf is usually reactive to environmental signal propagation; however, source‐to‐sink functioning can be further complicated by several allogenic forcings. Here, we document the high‐frequency provenance variations and different sediment delivery models recorded in the late Triassic Zhuoni fan developed in the northeastern Paleo‐Tethys Ocean, mainly based on process‐based sedimentological and provenance study of the Panyuan section in the West Qinling area in the northeastern margin of Tibetan Plateau. High‐, low‐density turbidites, hybrid event beds and hyperpycnites are distributed in the lobe‐dominated submarine fan succession. Field sedimentological evidence from surrounding outcrops suggests that shelf‐edge failure was the main cause of most high‐ and low‐density turbidites with the overall absence of submarine slides or slumps, whereas the narrow shelf configuration together with late Triassic humid pulses is favourable for the occurrence of flood‐related hyperpycnites in the Zhuoni fan. Detrital zircon grains (N= 6;n= 123–272) generally have Palaeozoic‐Mesozoic ages (ca. 350–250 Ma and 500–400 Ma) and Neoarchean‐Paleoproterozoic ages (ca. 2100–1750 Ma and 2600–2400 Ma), but they can be further categized into three age groups due to different proportions of Precambrian age populations. The results demonstrate that the potential source areas may include the South and North Qinling Orogenic Belt, Qilian Orogenic Belt, different segments of North China Craton and the tectonic junction area between the Qinling and Qilian Orogenic Belts. The temporal changes in provenance signals, which are reflected by both the detrital zircon age spectra and heavy mineral assemblages, indicate different contributions of those sources in response to sea‐level fluctuation. It could thus give rise to temporal variations between reactive and buffered source‐to‐sink sediment delivery models of the Zhuoni fan, despite the overall narrow shelf configuration. The development of the lowstand Zhuoni fan was directly related to extrabasinal hyperpycnal delivery from the river mouth and its high‐frequency provenance variability recorded different efficiencies of signal transfer through the onshore catchment with significantly influence of temporal storage, fluvial rejuvenation or even regional climate variability. The highstand submarine fan was thought to be formed by shelf‐edge failure with sediment buffering in the shelf region, which was associated with a strong magnitude of provenance mixing. Our work provides a new perspective for deciphering the different origins of deep‐water sediment delivery in response to high‐frequency sea‐level and climate changes.