Chronology,Geochemical Characteristics and Geological Significance of Middle Proterozoic Quartz Diorite in the Kalasitandaliya Area of Northern Kudi,Xinjiang
Previous scholars have insufficient understanding of the pre Cambrian magmatic activity and tectonic evolu-tion in the northern margin of the West Kunlun Mountains,resulting in significant differences.The author identified the Middle Proterozoic quartz diorite in the tectonic melange of the Kalastandailiya area in Kudi,and conducted geological,petrological,geochemical,and isotopic dating studies on it.The SiO2 content of quartz diorite ranges from 54.55%to 55.84%,MgO ranges from 5.42%to 5.65%,Ti2O content ranges from 1.15%to 1.57%,Mg# ranges from 57%to 58%,and the Rittmann index σ ranges from 1.57 to 1.80,belonging to the high potassium calcium alkaline series.The total amount of rare earth elements ∑ REE ranges from 150.5 to 183.68 ×10-6;(La/Yb)N ranges from 1.98 to 2.27,(La/Sm)N ranges from 1.39 to 2.08,and(Gd/Yb)N ranges from 1.00 to 1.01,δEu ranges from1.03 to 1.11.The U-Pb age of zircon obtained from quartz diorite is 1130.3±5.6 Ma.The formation of quartz diorite in the northern Kalastandailiya area of Ku-di in the western Kunlun Mountains dates back to the late Mesoproterozoic era,belonging to the Zanqi type high magne-sium diorite.It was formed by the reaction of mantle peridotite and subducted ocean sheets,and was formed in continen-tal island arc environment.It is the geological record of the subduction and subduction of oceanic crust towards the Tarim block during the Rodinia supercontinent aggregation process.
West KunlunSouth Kunlun BlockRodinia supercontinentMiddle ProterozoicQuartz dioriteSubduc-tion subduction