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Zircon U–Pb age constraints on the provenance of Upper Oligocene to Upper Miocene sandstones in the western Qiongdongnan Basin, South China sea
Marine and Petroleum Geology ( IF 3.7 ) Pub Date : 2020-12-30 , DOI: 10.1016/j.marpetgeo.2020.104891
Chengfu Lyu , Chao Li , Guojun Chen , Gongcheng Zhang , Ming Ma , Ying Zhang , Zhaotong Sun , Qianshan Zhou

The provenance of Upper Oligocene to Upper Miocene sandstones in the western Qiongdongnan Basin was studied by zircon U–Pb ages. More than 200 zircon grains were separated from the sandstone of the Upper Oligocene Lingshui, Lower Miocene Sanya, and Upper Miocene Huangliu formations, and spot analysed for U–Pb dating. Most zircon grains from the Upper Oligocene Lingshui and Upper Miocene Huangliu formations had rounded corners, suggesting that the grains were transported a relatively long distance before deposition, while grains from the Lower Miocene Sanya Formation were usually angular in shape, implying a shorter transport distance from their provenance. The Lingshui Formation contained exclusively Cenozoic, Mesozoic, Palaeozoic, and Proterozoic zircon ages, and the age spectrum showed two major peaks at ca. 247 and 441 Ma, along with nine subordinate age peaks at ca. 35, 305, 517, 623, 811, 852, 911, 1158, and 1905 Ma. This indicates that Upper Oligocene sediments in the northwestern area of the Qiongdongnan Basin may have originated from the Red River system, which had four major peaks at 254, 418, 751, and 1848 Ma, and five subordinate peaks at ca. 32, 81, 514, 606, and 967 Ma. Results suggest that sediments from the Red River system entered the Qiongdongnan Basin as early as the Late Oligocene. The zircon age spectrum of the Sanya Formation had two major peaks at 99 and 237 Ma, indicating that Lower Miocene sandstones in the northwestern area of the Qiongdongnan Basin were mainly from Hainan Island, with ages ranging from 110 to 90 to 280–220 Ma. This study infers that the sandstones may be the paleo-Red River capture by the Yangze River, which resulted in a large decrease of sediment supply from the paleo-Red River system, such that the sediments of the paleo-Red River did not develop in the western area of the Qiongdongnan Basin during the Early Miocene. Results indicate that if the Red River capture existed, it would have predated the Early Miocene. The zircon age spectrum from Upper Miocene sediments of the western Qiongdongnan Basin showed five major age peaks at ca. 27, 88, 256, 415, and 785 Ma, indicating that its provenance was the Red River system. The Late Miocene provenance change from Hainan Island to the Red River may have been in response to a major phase of the Tibetan Plateau uplift.



中文翻译:

南海西部琼东南盆地上渐新世至中新世上砂岩物源的锆石U–Pb年龄约束

利用锆石U–Pb年龄研究了琼东南盆地西部地区上渐新世至上中新世砂岩的物源。从上渐新世陵水,下中新世三亚和上中新世黄柳地层的砂岩中分离出了200多个锆石颗粒,并对其进行了U-Pb定年分析。上新世凌水和上中新世黄柳组的锆石颗粒大多具有圆角,这表明这些颗粒在沉积前被输送了相对长的距离,而下三新中三亚组的颗粒通常呈角形,这意味着距中新世三亚组的颗粒距离较短。他们的出处。陵水组仅含有新生代,中生代,古生代和元古代的锆石年龄,年龄谱显示在大约两个主要峰。247和441 Ma,以及大约9个从属年龄高峰。35、305、517、623、811、852、911、1158和1905 Ma。这表明琼东南盆地西北部的上渐新世沉积物可能起源于红河系,在254、418、751和1848 Ma处有四个主要峰,在ca处有五个次要峰。32、81、514、606和967 Ma。结果表明,红河流域的沉积物早于晚渐新世进入琼东南盆地。三亚组的锆石年龄谱在99和237 Ma处有两个主要峰值,表明琼东南盆地西北部的中新世砂岩主要来自海南岛,年龄在110至90至280-220 Ma之间。这项研究推断,砂岩可能是长江流域捕获的古红河,这导致了古红河系统的泥沙供应量大大减少,以致中新世早期琼东南南盆地西部地区的古红河沉积物没有发育。结果表明,如果存在红河捕获,那它将早于中新世。琼东南盆地西部中新世上新世沉积物的锆石年龄谱显示,约有五个主要年龄峰。27、88、256、415和785 Ma,表明其起源是红河系。从海南岛到红河的中新世晚期起源变化可能是由于青藏高原隆升的一个主要阶段。使得中新世早期琼东南盆地西部地区没有形成古红河沉积物。结果表明,如果存在红河捕获,那将早于中新世。琼东南盆地西部中新世上新世沉积物的锆石年龄谱显示,约有五个主要年龄峰。27、88、256、415和785 Ma,表明其起源是红河系。从海南岛到红河的中新世晚期起源变化可能是对青藏高原隆升的主要阶段的反应。使得中新世早期琼东南盆地西部地区没有形成古红河沉积物。结果表明,如果存在红河捕获,那将早于中新世。琼东南盆地西部中新世上新世沉积物的锆石年龄谱显示,约有五个主要年龄峰。27、88、256、415和785 Ma,表明其起源是红河系。从海南岛到红河的中新世晚期起源变化可能是由于青藏高原隆升的一个主要阶段。表明它的出处是红河系。从海南岛到红河的中新世晚期起源变化可能是由于青藏高原隆升的一个主要阶段。表明它的出处是红河系。从海南岛到红河的中新世晚期起源变化可能是由于青藏高原隆升的一个主要阶段。

更新日期:2021-02-07
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