Genetic relationship between eclogite, lamprophyre, gold deposit and enriched mantle of Su-Lu active continental margin in the Mesozoic, China.

The Initial Eurasia plate and Paleopacific plate started to converge intens ely at the end of Hercynian or beginning of the Triassic (250Ma). The subdu ction, its evolution and long distant effect are the foundamental factors c ontrolling the formation and evolution of the most granitoids, volcanics, l amprophyres and gold deposits in Jiaodong terrane. The characteristics of l amprophyres in Jiaodong terrane are similar to lamprophyres related to gold deposits in other active continental margin or orogenic belts. Such as dyk e occurrence, late-stage emplacement, intensive autometasomatism, enrichmen t in large ion lithophile element (LILE) and volatiles, higher content of g old, high ratios of LREE/HREE and Sr-87/Sr-86, low Nd-143/Nd-144 ratios, co mplementarity in many main and trace elements with eclogites, and intimate association with granotoids and shoshonite volcanics, other mafic rocks, fe lsic dyke and hydrothermal gold deposits. All these features could be relat ed to the enriched mantle wedge and explained by mantle-crust material exch ange due to degassification, dealkalization, desilicification and remobiliz ation of LILE during subduction of slab. The subduction and its evolution a re the foundamental factors controlling the formation and evolution of most granitoids, volcanics, lamprophyres and gold deposits in Jiaodong terrane. All these features could be related to the enriched manntle wedge and expl ained by mantle-crust material exchange during subduction of slab in active continental margin.