East Kunlun edge of the cloth Castle effective Stein ophiolite geology, age and tectonic environment of formation

Title: East Kunlun edge of the cloth Castle effective Stein ophiolite geology, age and tectonic environment of formationAuthor: Yu SunDegree-granting units: Chang'an UniversityKeywords: effective Stan ophiolite;; ancient ocean basin;; geochemistry;; LA-ICP-MS zircon U-Pb dating;; early Paleozoic;; original Tethys;; Animaqing - cloth Castle Peak tectonic belt;; East Kunlun edgeSummary:

Stan effective in the East Kunlun ophiolite edge Animaqing - Castle Peak tectonic belt western cloth, separating the north and south of the eastern Kunlun orogenic belt Hoh Xil - Bayan Har orogenic belt. In this paper, cloth Castle Peak area ophiolite Stan effective for the study, through detailed field line survey, focus and profile measurement system for analysis of indoor microscopic thin, ophiolites Stan on effective field distribution, an extension of the direction, size Neodymium Magnets and occurrence and rock assemblages, petrographic features in detail. Meanwhile, representative samples of the rock geochemical and isotopic dating test test, from geochemical and isotope geochronology of the effective aspects of Stan ophiolite tectonic environment and age, to obtain an initial understanding of the following:

Effective direction of Stan ophiolite extends to the North West, parallel to the East Kunlun fault. Ophiolite rock assemblages within the more complete, the south side of the bottom of the mantle rocks are altered by the dark green harzburgite (serpentinite), lherzolite composition, was constructed with the contact between the rock; diabase porphyrite were interspersed with rock-like dikes in serpentinite, the rock pulse width of 0.5m ~ 6m; north appear dark gray massive gabbro, cumulates is not obvious, and was constructed south of serpentinite contact relationship; most The upper part of gray-black basalt alteration, local shows pillow structure, was constructed with the gabbro contact relationships; ophiolite overlying sedimentary rocks of the deep gray-black silty mudstone, and the fault contact between the basalt.

Effective combination of Stan ophiolite serpentinite range of SiO2 content smaller, low-Ti depleted magnesium-rich potassium and sodium; http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets gabbro and diabase porphyry belong to the sub-alkaline series, the diagrams are located in the ACM mafic accumulation of rocky; sub-alkaline basalts are tholeiitic basalt series. Effective Stein ophiolite meta-peridotite chondrite-normalized curves are open "U" shape, cumulate peridotite slightly depleted LREE flat type; gabbro, diabase and basalt porphyry chondrite-normalized REE curves are very similar, are LREE depleted. In primitive mantle-normalized trace element on the curve, effective Stan ophiolite rock units in the large ion lithophile elements fluctuates significantly, the high field strength elements are relatively flat, without Nb, Ta, Ti losses, indicating that almost no continental crust by mixing dye, no island arc and oceanic island rock characteristics, and effective ingredients are very similar to the normal basalt Stan-ocean ridge basalt. Geochemical analysis shows that more effective Stein ophiolite probably formed in the normal mid-ocean ridge tectonic environment.

Effective Stein ophiolite gabbro of LA-ICP-MS zircon U-Pb weighted average age of (516.4 ± 6.3) Ma, shows effective Stein ophiolite formed in the early Cambrian, suggesting that the East Kunlun edge Animaqing - cloth Castle Tethyan tectonic belt is not only the existence of ophiolite, there are early Paleozoic Proto-Tethys ophiolite.

Stan by competent ophiolite detailed field geology, petrography, geochemistry and geochronology of the comprehensive study, this paper argues clamping block in East Kunlun and the Hoh Xil - between the Bayan Har block Early Paleozoic of the original Te Site Animaqing - cloth Castle ocean basin may be formed in the late Neoproterozoic - Early Cambrian, Late Cambrian began northward subduction, in the Late Ordovician oceanic crust to stop the expansion, along with continued subduction role Animaqing - cloth Castle residual ocean basin into basin. Silurian period, the north and south of the Hoh Xil East Kunlun block - Bayan Har blocks collision, the former Tethys ocean basin closure.Degree Year: 2010