Reconstruction the Process of Partial Melting of the Retrograde Eclogite from the North Qaidam, Western China: Constraints from Titanite U-Pb Dating and Mineral Chemistry

Retrograde eclogite and garnet amphibolite of the Luliangshan unit of the Shenglikou area, North Qaidam, were studied with emphasis on rutile and titanite. A special focus is on the formation of rutile and its corona of titanite (Ttn1) in retrograde eclogite and on coarse-grained titanite (Ttn2) from the garnet amphibolite. Using zirconium (Zr)-in-rutile and Zr-in-titanite thermometers, the temperatures estimated for the formation of an early...