EVIDENCE FOR TIBETAN PLATEAU UPLIFT BEFORE 14-MYR AGO FROM A NEW MINIMUM AGE FOR EAST-WEST EXTENSION
EVIDENCE FOR TIBETAN PLATEAU UPLIFT BEFORE 14-MYR AGO FROM A NEW MINIMUM AGE FOR EAST-WEST EXTENSION
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DOI：
10.1038/374049a0
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发表时间：
1995-03-02
期刊：
影响因子：
64.8
通讯作者：
HODGES, K
中科院分区：
文献类型：
--
作者：
COLEMAN, M;HODGES, K
南亚气候的重大变化发生在中新世晚期（类似于800万年前）（1，2），一些研究人员将其归因于大约在同一时间的青藏高原隆起（3 - 5）。不幸的是，这种联系一直难以检验，因为高原隆升的时间仍然没有受到独立证据的严格限制。确定最小隆升年龄的一种方法是确定藏南北向正断层系统的起始年龄，这些正断层系统被广泛认为（6 - 10）与青藏高原的重力塌陷有关。在这里，我们报告了一个40 Ar/39 Ar年龄类似于14百万年的热液云母从一个拉伸断裂属于这样一个断层系统在尼泊尔中北部。这个年龄意味着青藏高原至少部分地区的东西向伸展开始于1400万年前，这表明青藏高原在晚中新世之前就达到了高平均海拔。
IMPORTANT changes in South Asian climate occurred in the Late Miocene epoch (similar to 8 Myr ago)(1,2), and these have been attributed by some researchers to uplift of the Tibetan plateau at about the same time(3-5). Unfortunately, this link has been difficult to test because the timing of plateau uplift remains poorly constrained by independent evidence. One way to determine the minimum age of uplift is to establish the initiation age of the north-striking normal fault systems in southern Tibet that are widely regarded(6-10) as being related to gravitational collapse of the Tibetan plateau. Here we report an 40Ar/39Ar age of similar to 14 Myr for hydrothermal mica from an extensional fracture belonging to such a fault system in north-central Nepal. This age implies that east-west extension began before similar to 14 Myr ago in at least some parts of the Tibetan plateau, suggesting that the plateau attained its high mean elevation well before Late Miocene time.