分类： 地球科学 >> 地质学 分类： 地球科学 >> 固体地球物理学 分类： 地球科学 >> 地球化学 提交时间： 2017-10-26
摘要： A robust code, called Low-T Thermo, has been developed to combine low-T thermochronological data arbitrarily to model thermal history. After apatite fission-track age and confined length are decoupled into two completely independent data to inverse thermal history and thermal history inversion using mica Ar-Ar age or bedrock quartz optically stimulated luminescence age are developed, there are eight kinds of low-T thermochronological data used to inverse thermal history including apatite fission-track age, apatite fission-track confined length, zircon fission-track age, apatite (U–Th)/He age, zircon (U–Th)/He age, mica Ar-Ar, bedrock quartz optically stimulated luminescence age and vitrinite reflectance. A total of 247 kinds of combination modes can be used to jointly inverse thermal history in theory (except the eight single methods modelling). These arbitrary combinations are helpful to model thermal history with the “incomplete” low-T thermochronological data set regarded to be unuseful for thermal history modelling and reduce experimental cost. For arbitrary combination of different low-T thermochronological data, each low-T thermochronological method is independent incompletely and the equivalent p-value is used to be the identical evaluation indicator in the inverse process. The usefulness of the code is demonstrated by modelling thermal history of existing low-T thermochronological data in the areas of Dabie Mountain, Ahimanawa Range and Southern Alps.
分类： 地球科学 >> 空间物理学 提交时间： 2017-06-13
摘要： Low temperature thermochronology plays a key role in the study of tectonic evolution of the upper crust. The general application of thermal history modelling of apatite fission-track analysis requires both the parameters of the apparent age together with the confined track-length distribution of the spontaneous tracks. However, obtaining length data is relatively easy and does not require either irradiation or LA-ICP-MS commonly used for determining the uranium content of the grains for age dating. This leads to a shorter laboratory process. For this purpose, based on apatite U-Th/He method, this paper attempts to decouple apatite fission-track age from apatite fission-track length, and then combine the lengths with the respective apatite U-Th/He age to model the thermal history. Therefore, experiments were designed and conducted using a new program "Low-T Thermo". Results of this modelling are presented from the following experiments: apatite fission-track age combined with apatite U-Th/He age; apatite fission-track confined track-length distribution plus apatite U-Th/He age. The modelling precision using this method is related to the relative errors of the apatite U-Th/He ages and the helium diffusion model. This combination of apatite fission-track length and apatite U-Th/He ages has not been implemented before but is presented here as an alternative way of determining thermal histories without the addition of apatite fission-track ages.
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