Thermal evolution and exhumation history of the Uncompahgre Plateau (northeastern Colorado Plateau), based on apatite fission track and (U-Th)-He thermochronology and zircon U-Pb dating
Thermal evolution and exhumation history of the Uncompahgre Plateau (northeastern Colorado Plateau), based on apatite fission track and (U-Th)-He thermochronology and zircon U-Pb dating
复制标题
基于磷灰石裂变径迹、(U-Th)-He 热年代学和锆石 U-Pb 定年的安康帕格里高原（科罗拉多高原东北部）的热演化和折返历史
DOI：
10.1130/ges01415.1
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发表时间：
2017
期刊：
影响因子：
2.5
通讯作者：
J. Jacobs
中科院分区：
文献类型：
--
作者：
Christian Rønnevik;A. K. Ksienzyk;H. Fossen;J. Jacobs
在过去的二十年里，热年代学研究极大地增加了我们对科罗拉多高原(美国西部)新生代演化的了解。人们对高原的西南部特别感兴趣，这导致了关于科罗拉多河水系的抬升和河流切割的时间的争论。我们在这里结合磷灰石裂变径迹(AFT)和磷灰石(U-Th)-He(AHE)分析以及锆石U-Pb测年来研究科罗拉多高原东北部，特别是Uncomahgre高原和Unaweep峡谷，那里有两个相反方向的非常不寻常的排水模式。我们从不对比高原获得了12个AFT年龄：3个来自高原基底顶部的AFT年龄(65-63 Ma)，6个来自Unaweep峡谷(35-27 Ma)和3个来自高原东北边缘(33-17 Ma)的样品在始新世晚期至渐新世经历了完全的热重置。顶层基底样品的热史模拟显示，晚白垩世加热到至少90°C的温度，意味着沉积埋藏到∼3公里，然后在整个白垩纪末期到始新世冷却。而AHE年龄(38-31 Ma)表明，这些样品在始新世晚期至渐新世有较小的再加热至40-80℃。拉萨尔山熔岩中的锆石U-Pb结晶年龄为29.1±0.3 Ma。熔岩的AFT年龄范围为33~27 Ma，证实了这一浅层次火山侵入体的快速冷却。这种晚始新世至渐新世的岩浆作用导致了不压实高原大部分AFT(除顶部基底外)和AHE年龄的热重置，尽管样品采集在距离侵入体60公里的地方。在过去的5-10英里内，峡谷样本也经历了降温速度的增加。这种中新世-上新世冷却事件被解释为与峡谷切割有关的科罗拉多高原的区域抬升。
Over the past two decades, thermochronological studies have greatly increased our knowledge of the Cenozoic evolution of the Colorado Plateau (western United States). There has been particular interest in the southwestern part of the plateau, leading to debate regarding the timing of uplift and fluvial incision along the Colorado River system. We here combine apatite fission track (AFT) and apatite (U-Th)-He (AHe) analyses as well as zircon U-Pb dating to investigate the much less studied northeastern Colorado Plateau, particularly the Uncompahgre Plateau and the Unaweep Canyon, which has a very unusual drainage pattern in two opposite directions. We obtained 12 AFT ages from the Uncompahgre Plateau: 3 from the top of the basement of the plateau reveal Laramide ages (65–63 Ma), and 6 samples from the Unaweep Canyon (35–27 Ma) and 3 from the northeastern plateau margin (33–17 Ma) underwent complete thermal resetting in the late Eocene to Oligocene. Thermal history modeling of top basement samples reveals Late Cretaceous heating to temperatures of at least 90 °C, implying sedimentary burial to ∼3 km, followed by cooling throughout the latest Cretaceous to Eocene. However, AHe ages (38–31 Ma) indicate minor reheating to 40–80 °C for these samples in the late Eocene to Oligocene. Zircons from the La Sal Mountains laccolith gave an Oligocene U-Pb crystallization age of 29.1 ± 0.3 Ma. AFT ages from the laccolith range from 33 to 27 Ma, confirming rapid cooling of this shallow subvolcanic intrusion. This late Eocene to Oligocene magmatism caused thermal resetting of most of the AFT (except top basement) and AHe ages from the Uncompahgre Plateau, even though samples were collected as much as 60 km away from the intrusion. Canyon samples also underwent an increase in cooling rates in the past 5–10 m.y. This Miocene–Pliocene cooling event is interpreted as regional uplift of the Colorado Plateau associated with canyon incision.
影响因子：
18.3
作者：
Karlstrom, Karl E.;Lee, John P.;Shuster, David L.
通讯作者：
Shuster, David L.