THE ORIGIN OF INTRUSIVE ROCKS IN LIAONING PROVINCE

The intrusive rocks may be classified into the mantle-derlved,mantle-crust syntectic and crustal anatectic types,according to the geological characteristics, mineralization,REE,Sr and S isotopes,petrochemistry,trace elements, mineral geochemistry and accessory minerals of the intrusive rocks. Mantle-derived type The rocks of this type consist of basic-ultrabasic rocks and plagiogranite.Cr and Ni mineralizations are represented.The REE pattern of the plagiogranite is flat and ∑REE is low（＜10 ppm）.⁸⁷sr/⁸⁶sr≤0.704.The contents of alkali metals and related elements（Sr,Ba,Zr and F）are low. Mantle-crust syntectic type The rocks are represented by diorite,granodio- rite,porphyritic admellite and granite porphyry.The intrusion was accompanied by volcanic eruption.Mo,Cu,Pb,Zn and Au mineralizations are more common. There oceur porphyry deposits.REE is intermediate in content（150 ppm±on average）;⁸⁷Sr/⁸⁶Sr＞0.704.-0.708;crystal chemistry shows the biotite to be magmisio-biotite and magnesioferri-biotite;Al^VI＜0.3 and Mg＞1;accessory minerals（Cr and Ni）and high and the contents of alkali metals and related elements are intermediate. Crustal anatectic type The rocks of this type are dominated by porphyroid admellite,no volcanic rocks being present.The type is characterized by W mineralization,high ∑REE （＞200 ppm on average）,⁸⁷Sr/⁸⁶Sr＞0.710,Al^VI＞0.3 and Mg＜1.1.Crystal chemistry shows the biotite to be ferrebiotite.The contents of refractory elements are low and the contents of alkali metals and related elements are high.