Growth of Archean continental crust in oceanic island arcs
نویسندگان
چکیده
منابع مشابه
Continental crust generated in oceanic arcs
Thin oceanic crust is formed by decompression melting of the upper mantle at mid-ocean ridges, but the origin of the thick and buoyant continental crust is enigmatic. Juvenile continental crust may form from magmas erupted above intraoceanic subduction zones, where oceanic lithosphere subducts beneath other oceanic lithosphere. However, it is unclear why the subduction of dominantly basaltic oc...
متن کاملThe structural and geochemical evolution of the continental crust: Support for the oceanic plateau model of continental growth
T h e problem of the origin of the cont inental crust can be resolved into two fundamenta l quest ions: (1) the lo cation and mechani sms of init ial m a n t l e extract ion of the primitive crust and (2) the processes by which this primitive crust is converted into the cont inental crust that presently exists . W e know that Archean cont inen tal crust is compos i t iona l ly dist inct from ...
متن کاملChemical differentiation of the Earth: the relationship between mantle, continental crust, and oceanic crust
The average chemical compositions of the continental crust and the oceanic crust (represented by MORB), normalized to primitive mantle values and plotted as functions of the apparent bulk partition coefficient of each element, form surprisingly simple, complementary concentration patterns. In the continental crust, the maximum concentrations are on the order of 50 to 100 times the primitive-man...
متن کاملژئوشیمی و سنگ‌شناسی سنگ‌های آتشفشانی شمال‌شرق نراق: ماگماتیسم جزایر قوسی یا حواشی قاره‌ای فعال؟
The tectonic settings for the Urumieh-Dokhtar volcanic-plutonic belt provided by different reaserchers including active continental margin rift and post collisional settings. Geochemical and tectonic studies indicate that this belt belongs to the active continental margin. Basaltic andesite, andesite, trachy andesite, trachy dacite and dacitic rocks in NE Naragh, of the Urumieh-Dokhtar magmatic...
متن کاملArchaean zircons in Miocene oceanic hotspot rocks establish ancient continental crust beneath Mauritius
A fragment of continental crust has been postulated to underlie the young plume-related lavas of the Indian Ocean island of Mauritius based on the recovery of Proterozoic zircons from basaltic beach sands. Here we document the first U-Pb zircon ages recovered directly from 5.7 Ma Mauritian trachytic rocks. We identified concordant Archaean xenocrystic zircons ranging in age between 2.5 and 3.0 ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Geology
سال: 2012
ISSN: 1943-2682,0091-7613
DOI: 10.1130/focus042012.1