摘要
地壳早期演化研究的主题是探讨早期大陆形成、生长和再循环的地质过程及其地球化学和地球物理模式。由于陆上古老岩石分布极为有限,围绕着陆壳生长速率的争论持续了30多年。地球化学家基于陆壳从地幔萃取而成并导致被萃取后的地幔在地球化学上产生亏损的认识,提出了许多重要的大陆形成、生长、再循环模式。近年来发展起来的高精度MC ICPMS分析技术,使单颗粒锆石Lu Hf同位素系统分析为评价早期地壳演化提供了更多的信息和更为可靠的证据。不同大陆早前寒武纪地壳及地幔地球物理和地球化学状态研究表明,陆壳再循环作用、壳—幔以及壳内(如古老的地壳重熔作用及其与相对较新的地壳发生广泛的混合作用)相互作用是早期大陆演化的重要地质过程。
The topic of the study of the evolution of early crust is to probe into the processes of early continental formation, growth, and recycling, and their geochemical and geophysical models. The debate upon the continental growth rate has been lasting for over 30 years due to the constraints of distribution of a very small amount of ancient rocks in the continental crust. Based on the knowledge of the continent extracted from the underlying mantle, and of relative depletion of the extracted mantle, geochemists have proposed many important models for the continental formation, growth, and recycling. With advances in geological chronology, especially in the recently developed MC-ICPMS which allows precise analysis of Hf grain by grain from a detrital zircon rather than in bulk, it can provide much more information and more reliable evidence for us to elucidate successfully the earliest history of the continental crust. The researches of geophysics and geochemistry of the crust and mantle in early Precambrian continental blocks show that the continental recycling, crust-mantle interaction and intracrustal reworking (e.g. the remelting of significantly older crust and subsequently extensive mixing between the melts and relatively new crust) might have been important processes from earliest time.
出处
《地球科学进展》
CAS
CSCD
2004年第4期591-598,共8页
Advances in Earth Science
基金
国家自然科学基金项目"华北地台北缘西段中元古代至早古生代地壳演化及成矿"(编号:49582152)资助
关键词
早前寒武纪
岩石圈地幔
地壳演化
陆壳生长
陆壳再循环
Early Precambrian
Lithospheric mantle
Crustal evolution
Continental growth and recycling.
