Thermal modeling of the Southern Alps, New Zealand
Thermal modeling of the Southern Alps, New Zealand
复制标题
新西兰南阿尔卑斯山的热力模拟
DOI：
10.1007/bf00874730
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发表时间：
1996
影响因子：
2
通讯作者：
F. Davey
中科院分区：
文献类型：
--
作者：
Yaolin Shi;R. Allis;F. Davey
横跨新西兰南阿尔卑斯山的热状况的有限元模拟已经进行了沿着两个配置文件位于附近的弗朗兹约瑟夫和哈斯特山谷。建模涉及南阿尔卑斯山下的粘性变形，包括隆起和侵蚀，以及地壳/岩石圈增厚，作为地壳缩短延伸到20毫米/年的25公里厚的地壳的结果。沿这两个剖面公布的抬升速率和地壳厚度变化沿着被用来约束模拟的地壳物质平流，并将结果与最近的热流测定结果进行比较，Franz Josef谷为190±50 mW/m2，Haast谷为90±25 mW/m2。将该模型与已发表的K-Ar和裂变径迹年龄进行比较，结果表明，如果现今的抬升速率接近10 mm/y，则在弗朗兹约瑟夫山谷观测到的热流与观测到的大约1 Ma的锆石裂变径迹年龄相一致。弗朗兹约瑟夫和哈斯特配置文件之间的主要热差异似乎是由于不同的隆起和侵蚀速率。有微弱的证据表明，靠近阿尔卑斯山断裂带的摩擦加热是不显着的。该模型提供了解释南阿尔卑斯山下的地震活动的分布，并预测低的地表热流在东部山麓，由于该地区下地壳增厚的主要热效应。最大隆起速率区下方中地壳深度的预测温度比先前公布的模型所显示的温度低50-100°C，这意味着地壳的热弱化可能不是造成南阿尔卑斯山中部地震活动的主要因素。建模的结果表明，不同类型的重置年龄数据在该地区的阿尔卑斯山断层25公里内的变形和热制度下的南阿尔卑斯山的约束模型是至关重要的。
Finite-element modeling of the thermal regime across the Southern Alps of New Zealand has been carried out along two profiles situated near the Franz Josef and Haast valleys. The modeling involves viscous deformation beneath the Southern Alps, including both uplift and erosion, and crustal/lithospheric thickening, as a result of crustal shortening extending to 20 mm/y of a 25-km thick crust. Published uplift rates and crustal thickness variations along the two profiles are used to constrain the modeled advection of crustal material, and results are compared with the recent heat flow determinations, 190±50 mW/m2 in the Franz Josef valley and 90±25 mW/m2 in the Haast valley. Comparisons of the model with published K−Ar and fission track ages, show that the observed heat flow in the Franz Josef valley is consistent with observed zircon fission track ages of around 1 Ma, if the present-day uplift rate is close to 10 mm/y. Major thermal differences between the Franz Josef and Haast profiles appear to be due to different uplift and erosion rates. There is weak evidence that frictional heating close to the Alpine fault zone is not significant. The modeling provides explanations for the distribution of seismicity beneath the Southern Alps, and predicts a low surface heat flow over the eastern foothills due to the dominant thermal effect of crustal thickening beneath this region. Predicted temperatures at mid-crustal depth beneath the zone of maximum uplift rate are 50–100°C cooler than those indicated in previously published models, which implies that thermal weakening of the crust may not be the main factor causing the aseismicity of the central Southern Alps. The results of the modeling demonstrate that the different types of reset age data in the region within 25 km of the Alpine fault are critical for constraining models of the deformation and the thermal regime beneath the Southern Alps.