Yidun Arc, Eurasian Platei

Regional Level Types
Yidun Arc	Terrane
Eurasian Plate	Tectonic Plate

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The Yidun terrane is bounded by the Ganzi-Litang and Jinshajiang suture zones to the east and west, respectively. It is sandwiched between the Songpan-Ganzi terrane and the Qiangtang terrane. The basement of the Yidun terrane is a sedimentary construction sequence formed prior to the Triassic. The oldest rock record found in the region is the Precambrian basement, covered by the Sinian Guanyinya Group and Dengying Group and controlled by the subduction of the Paleo-Tethyan slab, with three volcanic-magmatic arc belts. From west to east, they are the Zaduo-Jinghong volcanic arc, the Jiangda-Weixi volcanic arc, and the Yidun volcanic arc. The Yidun volcanic arc, the largest among the three volcanic arcs, extends 500 km from north to south, and there are large-scale Mesozoic volcanic and magmatic activities with many metal ore deposits.

Associated with multiphase magmatism and intense tectonic activity, the Yidun Terrane hosts numerous mineral deposits of various types and sizes, controlled by complex geological factors. Based on genetic type, the deposits in the region can be grouped into three categories: (1) Marine volcanic exhalative–hydrothermal Cu–Pb–Zn–Ag polymetallic deposits associated with island-arc volcanic and subvolcanic rocks in an Indosinian high-angle oceanic-subduction intra-arc rift setting, including representative volcanogenic massive sulfide (VMS) deposits rich in Cu, Pb, Zn and Ag). (2) Porphyry and hydrothermal–skarn deposits related to intermediate to felsic porphyries (e.g., quartz diorite and quartz monzonite porphyry) in an Indosinian arc/intra-arc environment). (3) Post-collisional to post-subduction magmatic–hydrothermal and contact metasomatic (skarn) polymetallic deposits associated with intermediate to acidic granitoid magmatism. This group includes Sn–Ag–Pb–Zn mineralization developed in a post-collision extensional setting following the Late Yanshanian arc–continent collision, as well as Late Cretaceous porphyry–skarn Cu–Mo–W polymetallic deposits interpreted to have formed in a post-subduction setting).

Commodity List

This is a list of exploitable or exploited mineral commodities recorded from this region.

Mineral List

Mineral list contains entries from the region specified including sub-localities

146 valid minerals. 1 erroneous literature entry.

Rock Types Recorded

Rock list contains entries from the region specified including sub-localities