Potassium isotopes trace the formation of juvenile continental crust  

作　　者：Hamed Gamaleldien Kun Wang Tim E.Johnson Jian-Feng Ma Mohamed Abu Anbar Xinmu J.Zhang Hugo K.H.Olierook Christopher L.Kirkland 

机构地区：[1]Department of Earth Sciences,College of Engineering and Physical Sciences,Khalifa University,Abu Dhabi,United Arab Emirates [2]School of Earth and Planetary Sciences,Curtin University,GPO Box U1987,Perth,WA 6845,Australia [3]Department of Earth,Environmental,and Planetary Sciences and McDonnell Center for the Space Sciences,Washington University in St.Louis,MO 63130,USA [4]Timescales of Mineral Systems Group,School of Earth and Planetary Sciences&John de Laeter Centre,Curtin University,Australia [5]Key Laboratory of Mineralogy and Metallogeny,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou,China [6]Geology Department,Faculty of Science,Tanta University,31527 Tanta,Egypt

出　　处：《Geoscience Frontiers》2024年第6期37-42,共6页地学前缘（英文版）

基　　金：the Editorial Advisor Prof.M.Santosh,Associate Editor Dr.S.Glorie,and two anonymous reviewers for their comments.H.G.acknowledges funding from the Khalifa University start-up fund(8474000697/FSU-2024-006);K.W.acknowledges support from the McDonnell Center for the Space Sciences and NASA(Emerging Worlds Program Grant No.#80NSSC21K0379);T.E.J.acknowledges funding from the Australian Government through an Australian Research Council Discovery Project(DP200101104)。

摘　　要：Constraining the processes associated with the formation of new(juvenile)continental crust from mantle-derived(basaltic)sources is key to understanding the origin and evolution of Earth’s landmasses.Here we present high-precision measurements of stable isotopes of potassium(K)from Earth’s most voluminous plagiogranites,exposed near El-Shadli in the Eastern Desert of Egypt.These plagiogranites exhibit a wide range of d41K values(–0.31‰±0.06‰to 0.36‰±0.05‰;2 SE,standard error)that are significantly higher(isotopically heavier)than mantle values(–0.42‰±0.08‰).Isotopic(87Sr/86Sr and^(143)Nd/^(144)Nd)and trace element data indicate that the large variation in d41K was inherited from the basaltic source rocks of the El-Shadli plagiogranites,consistent with an origin through partial melting of hydrothermally-altered mid-to-lower oceanic crust.These data demonstrate that K isotopes have the potential to better constrain the source of granitoid rocks and thus the secular evolution of the continental crust.

关 键 词：Potassium isotopes Plagiogranites Arabian-Nubian Shield NEOPROTEROZOIC Crustal growth 

分 类 号：P542[天文地球—构造地质学]