Petrogenesis of diabase from Jiangshiqiao in Taojiang City, Hu'nan Province:Constrains from geochemistry, geochronology and Sr-Nd-Pb isotopes

Zircon LA-ICP-MS U-Pb dating for diabase from Jiangshiqiao in Taojiang City of Hu'nan Province yielded an emplace-ment age of 229±2.3Ma (n=8, MSWD=1.8, 2σ).The diabase is characterized by low values of potassium (K₂O/Na₂O=0.14~0.16), and alkali (K₂O+Na₂O=2.89%~2.96%), enrichment of large ion lithophile elements and LREE and depletion of high field strength el-ements, low (⁸⁷Sr/⁸⁶Sr)_i ratios (0.70606~0.70644), low positive ε _Nd(t) values (1.55~1.87) and enrichment of radioactive Pb, suggesting a mixed source of the depleted mantle (DM) and the lower crustal.In combination with previous studies, the authors hold that the di-abase was formed through partial melt of the mantle and lower crustal components by the upwelling asthenosphere during the Indo-sinian post-orogenic lithosphere extension in Hu'nan Province.