Minerals respond texturally and compositionally to changing magmatic environments and preserve a wealth of information regarding magmatic processes and compositions in their crystal-growth stratigraphy. This book reports the detailed petrography and in-situ geochemistry of the clinopyroxene phenocrysts of the mafic dykes in the Jiaodong Peninsula, southeastern North China Craton, including in-situ determinations of major elements, trace elements, Sr isotopic compositions, and H2O contents with further constraints on the petrogenesis and geodynamics of the mafic dykes. Systematic analyses of mineralogical, major, and trace elements, Sr–Nd isotopes, and in-situ S isotopes on the pyrite of the main gold-bearing mineral assemblages and visible gold were conducted, aiming to explore the source of ore-forming materials and the process of Au element migration and deposition. The geodynamic setting of mineralization in the studied region is also summarized.