A review of the W isotope research for the Earth's core-mantle interaction

• Published in: Acta Petrologica Sinica
• Main Authors: Yang Zhen, Wang GuiQin, Xu YuMing, Zeng YuLing
• Format: Report
• Language: English
• Published: SCIENCE PRESS 2022
• Subjects: Geology; W isotope; Core-Mantle Interaction; Mantle plume; Ocean island basalt; Flood basalt; Baffin Bay; Baffin; Ocean Island
• Online Access: http://ir.gig.ac.cn/handle/344008/65022; https://doi.org/10.18654/1000-0569/2022.06.07

The challenge of studying the Earth's core-mantle interaction is that the samples at the boundary between core and mantle cannot be obtain by current technology. Ocean island basalts and flood basalts are considered to be the products of decompression-melting of mantle plumes, which carry the materials in the core-mantle boundary and are the best samples for researching the core-mantle interaction in the Earth. The isotope of W-182 becomes an important tool for researching the Earth's core-mantle interaction because the unique geochemical properties of Hf-182-W-182 isotope system. This paper introduces the basic principle of W isotope as tracer and reviews the research progress of W isotope in the Earth's core-mantle interaction The published data has shown that the global oceanic island basalts are characterized by W content enrichment (67 Chi 10(-9) similar to 855 Chi 10(-9)) and W-182 isotope depletion (mu W-182 = -0.1 similar to - 16.1 other hand, the flood basalts from the Baffin Bay and Ontong Java Plateau are characterized by enrichment of W-182 (mu W-182 =23.4), which indicate these samples might be derived from the "Early Formed Mantle Reservoir". The difference of mu W-182 between ocean island basalts and flood basalts might be caused by the heterogeneity of mantle plumes (eg. head-positive vs. tail-negative). In addition, the mu W-182 anomaly could also be caused by other reasons, such as it might be from isolated preservation of primitive mantle reservoirs, or partial mixing of the late veneer, or inefficient differentiation of the Earth core-mantle, and so on. However, the core-mantle exchange mechanism of W isotopes is still controversial.