کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4715503 1638646 2016 20 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Petrogenesis of early Jurassic basalts in southern Jiangxi Province, South China: Implications for the thermal state of the Mesozoic mantle beneath South China
ترجمه فارسی عنوان
پتروژنز بازالت های زودرس ژوراسیک در جنوب جیانگشی استان جنوب چین: پیامدهای وضعیت حرارتی گوشته مزوزوئیک زیر جنوب چین
کلمات کلیدی
بازالت، زودرس ژوراسیک، حالت حرارتی مانت، استان جیانگشی جنوبی، استان جنوب غربی چین و منطقه ماگما
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات ژئوشیمی و پترولوژی
چکیده انگلیسی


• Bimodal volcanic rocks from southern Jiangxi Province erupted at ca. 190 Ma.
• The basalts were derived from the asthenospheric mantle.
• Numerical simulation results constrain a partial melting pressure of 1.9–2.1 GPa and an average mantle potential temperature at 1400 °C.
• A Basin and Range-type lithosphere existed in South China during the Early Jurassic.

Early Jurassic bimodal volcanic and intrusive rocks in southern South China show distinct associations and distribution patterns in comparison with those of the Middle Jurassic and Cretaceous rocks in the area. It is widely accepted that these rocks formed in an extensional setting, although the timing of the onset and the tectonic driver for extension are debated. Here, we present systematic LA–ICP–MS zircon U–Pb ages, whole-rock geochemistry and Sr–Nd isotope data for bimodal volcanic rocks from the Changpu Formation in the Changpu–Baimianshi and Dongkeng–Linjiang basins in southern Jiangxi Province, South China. Zircon U–Pb ages indicate that the bimodal volcanic rocks erupted at ca. 190 Ma, contemporaneous with the Fankeng basalts (~ 183 Ma). A compilation of geochronological results demonstrates that basin-scale basaltic eruptions occurred during the Early Jurassic within a relatively short interval (< 5 Ma). These Early Jurassic basalts have tholeiitic compositions and OIB-like trace element distribution patterns. Geochemical analyses show that the basalts were derived from depleted asthenospheric mantle, dominated by a volatile-free peridotite source. The calculated primary melt compositions suggest that the basalts formed at 1.9–2.1 GPa, with melting temperatures of 1378 °C–1405 °C and a mantle potential temperature (TP) ranging from 1383 °C to 1407 °C. The temperature range is somewhat hotter than normal mid-ocean-basalt (MORB) mantle but similar to an intra-plate continental mantle setting, such as the Basin and Range Province in western North America. This study provides an important constraint on the Early Jurassic mantle thermal state beneath South China.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Lithos - Volumes 256–257, July 2016, Pages 311–330
نویسندگان
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