High-precision 40Ar/39Ar age for the Jehol Biota
High-precision 40Ar/39Ar age for the Jehol Biota
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热河生物群高精度40Ar/39Ar年龄
DOI：
10.1016/j.palaeo.2009.06.021
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发表时间：
2009-09-01
影响因子：
3
通讯作者：
Fang, Yan
中科院分区：
文献类型：
--
作者：
Chang, Su-chin;Zhang, Haichun;Fang, Yan
在内蒙古、河北和辽宁的义县组及其上覆的九佛堂组中发现了丰富的陆生热河生物群化石，包括植物、昆虫、恐龙、鸟类、哺乳动物和淡水无脊椎动物。热河生物群因其化石保存的特殊性而成为中生代最重要的化石群之一，被称为“中生代庞培”。热河生物群提供了一个难得的机会来解决有关鸟类起源，羽毛和飞行的进化，被子植物的早期多样化和胎盘哺乳动物辐射的时间问题。对辽西典型露头附近的土城子组、义县组和九佛堂组的6个凝灰岩样品和2个玄武岩样品进行了高精度的40 Ar/39 Ar年龄测定。义县组底部玄武岩的年龄为129.7 ± 0.5Ma，上覆九佛堂组底部凝灰岩的年龄为122.1 ± 0.3Ma。我们的年龄结果提供了整个义县组的年龄校准，并表明整个形成的沉积完全在早白垩世的时间超过了类似的7马的时间间隔。(C)2009 Elsevier B. V.保留所有权利。
Abundant fossils of the terrestrial Jehol Biota, including plants, insects, dinosaurs, birds, mammals and freshwater invertebrates, were discovered from the Yixian Formation and the overlying Jiufotang Formation in Inner Mongolia, Hebei Province and Liaoning Province, northeastern China. Because of the exceptional preservation of fossils, the Jehol Biota is one of the most important Mesozoic lagerstatten and is referred to as a "Mesozoic Pompeii". The Jehol Biota has provided a rare opportunity to address questions about the origin of birds, the evolution of feathers and flight, the early diversification of angiosperms and the timing of placental mammal radiation. Six tuff samples and two basalt samples collected from the Tuchengzi, the Yixian and the Jiufotang formations near the classic outcrops in western Liaoning, NE China yielded high-precision 40Ar/39Ar ages. We obtain an age of 129.7 +/- 0.5 Ma for a basaltic lava from the bottom of the Yixian Formation and an age of 122.1 +/- 0.3 Ma for a tuff from the lowermost part of the overlying Jiufotang Formation. Our age results provide an age calibration of the whole Yixian Formation and show that the whole formation was deposited entirely within Early Cretaceous time over an interval of similar to 7 Ma. (C) 2009 Elsevier B.V. All rights reserved.