The Dakendaban Group was mainly composed of biotite plagiogneiss, migmatite, biotite-quartz schist, plagioclase amphibolite and marble in the Erlangdong area at the northern margin of Qaidam Basin. Internal structure analysis show that most of them exhibit core-rim structure. The core and rim of zircon are typical magmatic and metamorphic zircon, respectively. Zircon dating yielded Early Cambrian age of 503.8±5.1 Ma and 493.6±4.5 Ma for the core, but Late Ordovician age of 449±9.9 Ma for the rim. The former represented the protolith age of migmatite biotite plagioclase gneiss, and the later reflected the time for metamorphism. The protolith and metamorphism age of the migmatitic biotite plagioclase gneiss were consistent with the time of arc magmatism and ultra-pressure metamorphism on the northern margin of Qaidam Basin. Our research proved the Dakendaban Group was not only comprised of Neoarchean-Paleoproterozoic rocks, but also contained Early Paleozoic rock assemblage, which is a melange composed of different times and different genesis rocks.
. SHRIMP zircon dating for migmatitic biotite plagioclase gneiss from Erlangdong Dakendaban Group in Wulan at the northern margin of Qaidam Basin and its geological significance[J]. Chinese Journal of Geology, 2015, 50(3): 728-740.