Low Temperature Thermochronology Reveals Tilting of Crystalline Bodies, Halilaga Porphyry Cu-Au Deposit, Nw Anatolia: Implications for Exploration of Porphyry Copper Deposits and Interpretation of Low-Temperature Thermochronology Data for Regional Tectonics

Abstract

Because most crystalline bodies lack intrinsic paleo-horizontal information, their tilting cannot be measured directly. Their vertical movement, however, may be tracked by low-T thermochronology (LTT) tools. Because tilting is caused by differential vertical movements, it can be understood if the rate of differential movements is determined. In this regard, here we apply a new LTT-based approach to calculate the orientation of a tilted crystalline body, the Halilaga Cu-Au deposit, in NW Anatolia. Orientation is consistent with the one calculated from a drillhole-based 3D model of the deposit. This reveals the significance of tilting calculations for the exploration of porphyry Cu deposits. On the other hand, and more importantly, it emphasizes the importance of tilting calculations for geological applications such as LTT-based exhumation histories of samples taken from vertical profiles, and paleomagnetic studies. AHe data from the Halilaga deposit reveals the earliest response to the Aegean back-arc extension at similar to 24 Ma in the north of Western Anatolia. Lastly, thermal models, the new complementary datasets for the tectonic evolution of the region, show that the Halilaga deposit was exhumed to the surface by the coupling effects of Aegean extension and westward propagation of the North Anatolian Fault, which occurred not earlier than 2 Ma.