Geochemistry Characteristics Of Boron-bearing Series In South JiLin

This dissertation based on the analysis of rockforming element, trace element and REE in Boron-bearing formation of Jilin. We restored parent rock formation by analyzing the petrology-geochemical characteristics of every kind of rocks in Boron-bearing formation. Checking out parent rock type of ore-bearing metamorphic formation and conforming the source of metallogenic material of boron deposits, and then providing the evidence for figuring out the deposit model.The Liao-Ji boron deposits are metasomatic hydrothermal deposit, which only was found in china. They are located in proterozoic Liao-Ji rift zone of china. We classified the boron-bearing formation into: bedded migmatite lecucoleptite complex Formation, Fe-Mg borate Formation, Boron-rich silicate Formation and metamorphic complex Formation. The migmatite leucoleptite complex Formation mainly consist of leptite, magmatite-leptite, amphibole banded migmatite and flesh red amphibole banded migmatite; Fe-Mg borate Formation is a sort of camsellite-bearing Mg-meta-igneous rocks; Boron-rich silicate Formation include tourmaline-granulite, biotite-granulite, leptite and some other metamorphic rocks; quartzite, mono-mica schist, biotite-granulite with amphibolite composed metamorphic complex Formation, around part of which there are some kind of migmatize. Main element, trace element and REE of amphibolite show the following characteristics: the original boron-accumulating setting is volcanic rocks, the parent rocks have low Mg and alkaline, belonging to a uniform type- argillic rocks. The granulite have different kinds of original rocks, which are volcanic, hydrothermal-sedimentary, marine-sedimentary, some leptites are associated with hydrothermal-sedimentary. The REE distribution of tourmaline-granulite are similar with biotite-granulite, parent rocks of which mainly are sedimentary rocks. The intergrowth of bedded amphibolite and banded migmatite give a clue: they aren't single magma granite, but multi-source migmatite that are attributed to remelt of igneous and sedimentary rocks.Comprehensively, every rock in Boron-bearing Formation is rich in B. Because wide regional metamorphism, the rock generally included tourmaline, to some extreme extent, some become into tourmaline-granulite.According to genesis of tourmaline, it came from tourmaline rocks and tourmalite during hydrothermal sedimentary process; tourmaline-granulite of regional metamorphism; tourmaline-quartz vein/tourmaline vein of migmatism. The enrichment index of common granulite in Jian is about 50, but of tourmaline-granulite is up to 500-4600, this process is the elementary enrichment of boron.