热年代学年龄温度法和年龄高程法的应用条件:对采样策略及年龄表达的启示  

Restriction on the application of thermochronologic age-temperature and age-elevation relationships: Some insights into sampling strategies and age interpretation

作　　者：曹凯[1,2] 王国灿[1,2] Peter van der Beek 

机构地区：[1]中国地质大学地质过程与矿产资源国家重点实验室,湖北武汉430074 [2]中国地质大学(武汉)地球科学学院,湖北武汉430074 [3]Institut des Sciences de la Terre,Université Joseph Fourier

出　　处：《地学前缘》2011年第6期347-357,共11页Earth Science Frontiers

基　　金：中国地质调查局项目"青藏高原新近纪隆升过程与地质事件群研究"(1212011121261)和"青藏高原新生代地质作用过程与第四纪环境演变综合研究"(1212010610103);中国地质大学研究生学术创新与探索基金(CUGYJS0801)

摘　　要：热年代学的年龄温度法和年龄高程法是研究造山带长期构造演化过程的常用方法。相对于年龄温度法而言,年龄高程法在计算岩石剥露速率上的优势在于回避了地温梯度的假设,但前提条件中最重要的方面则要求地温梯度达到稳定状态。然而,地温场通常会受到地形变化、地表剥露速率、断层活动及岩浆侵入等作用的干扰,导致地温梯度处于非稳定状态。此时,针对造山带长期演化过程中的具体问题采取合理的热年代学采样策略以及对年龄信息的有效提取方法是十分必要的。Thermoehronologic age-temperature and age-elevation relationships are commonly used to quantitatively constrain the long-term tectonic evolution of an orogen. In contrast to the agetemperature rdationship, the age-elevation relationship has more advantages in calculating exhumation rates of rocks without the imposed geothermal gradient. However, the potential functions of the age-elevation relationship in extracting cooiing and exhumation signals of rocks need the presupposition of stable geothermal gradient. But the complicated effects （e. g. the relief change, exhumation rate, magma emplacement, etc. ） will unpredictably perturb the geothermal field, producing the unstable geothermal gradient. As such, aiming at some specific projects, it is essential to adopt suitabl; sampling strategies and promising methods to unveil the information hidden in the thermochronologic ages.

关 键 词：热年代学 年龄温度法 年龄高程法 地温梯度 采样策略 

分 类 号：P597.3[天文地球—地球化学]