Conodont (U–Th)/He thermochronology: Initial results, potential, and problems
Conodont (U–Th)/He thermochronology: Initial results, potential, and problems
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DOI：
10.1016/j.epsl.2007.04.022
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发表时间：
2007-06
影响因子：
5.3
通讯作者：
D. Peppe;P. Reiners
中科院分区：
文献类型：
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作者：
D. Peppe;P. Reiners
我们进行了He扩散实验和（U-Th）/He年龄测定牙形刺从不同的位置，探讨牙形刺（U-Th）/He热年代学的潜力，以约束一些沉积岩为主的地形的热历史和折返。根据两个扩散实验和一些样品的年龄结果，He在牙形石元素中的扩散似乎与尺寸相似的杜兰戈磷灰石碎片中的扩散相似，闭合温度约为60-70 °C（冷却速率为10 °C/m.y.）。某些地区牙形石的（U-Th）/He年龄与区域热历史约束一致，至少在两种情况下，封闭温度低于1080 °C。然而，其他样品产生不可重现的年龄，在一种情况下，产生的年龄比基于区域地质考虑的预期要年轻得多。这些不可重复的样品显示出与晚期开放系统U-Th行为一致的母核素和年龄之间的负相关性。
We performed He diffusion experiments and (U–Th)/He age determinations on conodonts from a variety of locations to explore the potential of conodont (U–Th)/He thermochronology to constrain thermal and exhumation histories of some sedimentary-rock dominated terrains. Based on two diffusion experiments and age results from some specimens, He diffusion in conodont elements appears to be similar to that in Durango apatite fragments of similar size, and closure temperatures are approximately 60–70 °C (for cooling rates of ∼10 °C/m.y.). (U–Th)/He ages of conodonts from some locations yield reproducible ages consistent with regional thermal history constraints and, in at least two cases, require a closure temperature lower than ∼80 °C. Other samples however, yield irreproducible ages, and in one case yield ages much younger than expected based on regional geologic considerations. These irreproducible samples show inverse correlations between parent nuclides and age consistent with late-stage open-system U–Th behavior.