Geochemical probing of continental lithosphere through time in transported terranes

地球化学研究表明，与裂谷有关的玄武岩典型地继承了其地幔源的同位素特征。大多数研究集中在一个狭窄的时间间隔内的火山岩或深成岩套，然后将这些岩石与邻近地体的同时期套进行比较。我的方法是在很长一段时间内研究特定地形中与裂谷有关的火成岩套的地球化学/同位素特征。这种方法使我能够在各种构造环境下评估地壳与下垫的次大陆岩石圈地幔（SCLM，刚性岩石圈板块的下部）之间的长期关系，并确定地壳与SCLM是否在裂谷、漂移和增生等主要构造事件中耦合。在这些事件中，地壳与陆地层之间潜在的耦合/解耦对于识别和理解全球尺度的构造和岩浆过程至关重要。陆地自旋力变化的证据（或缺乏证据）将回答一些重要的地球动力学问题，如(i)陆地在跨越海洋时是否保留其陆地自旋力？（ii）在碰撞造山作用后，SCLM是否被替换？（iii）超羽流是否取代了超大陆下的旋流层？（iv）地壳和陆地板块之间的耦合是持久和普遍的，还是随着时间的推移而变化，如果是，是什么时候，为什么？

Geochemical studies show that rift-related basaltic rocks typically inherit the isotopic signature of their mantle sources. Most studies focus on suites of volcanic or plutonic rocks that were emplaced within a narrow time interval and then compare these rocks with coeval suites in adjacent terranes. My approach is to investigate the geochemical/ isotopic characteristics of rift-related igneous suites in specific terranes over a long range of time. This approach enables me to evaluate the long-term relationship between the crust and the underlying sub-continental lithospheric mantle (SCLM, the lower part of the rigid lithospheric plate) in a variety of tectonic settings, and to determine whether or not the crust and SCLM were coupled during the major tectonic events such as rifting, drifting and accretion. The potential coupling/decoupling between the crust and the SCLM during these events is critical to the identification and understanding of the global-scale tectonic and magmatic processes. Evidence (or a lack thereof) for changes in the SCLM will answer important geodynamic questions such as (i) do terranes retain their SCLM when transferred across an ocean? (ii) is the SCLM replaced following collisional orogenesis? (iii) do superplumes replace the SCLM beneath supercontinents? and (iv) is coupling between the crust and SCLM enduring and common or does it change with time, and if so, when and why?