The Paleoproterozoic boron deposits in east Liaoning occur in Mg-rich marble of Li’eryu Formation of Liaohe group. The mineralization was controlled by stratigraphic lithology. The volcano-sedimentation is the materi...The Paleoproterozoic boron deposits in east Liaoning occur in Mg-rich marble of Li’eryu Formation of Liaohe group. The mineralization was controlled by stratigraphic lithology. The volcano-sedimentation is the material base of ore- formation. Boron mainly derived from volcanic source. Boron in Li’ eryu formation was activated and transferred by mignati- zation and then deposited into ore when metasomatism occurrs in Mg-rich marble. Structural deformation reconstructed the boron ore bodies. Meanwhile, ore-bearing hydrothermal solution produced by structural deformation and remetasomated the host-ore rocks or filled in fissure of ore. Boron deposit is a stratabound deposit, which formed by mignatization and structu- ral deformation mineralization.展开更多
Continental growth is episodic,and arc-continentalmargin has importance for the formation of continentalcrust in the Shyok Suture Zone(SSZ).To shed light onthe petrogenesis of mantle derived orthogneiss and hybridsour...Continental growth is episodic,and arc-continentalmargin has importance for the formation of continentalcrust in the Shyok Suture Zone(SSZ).To shed light onthe petrogenesis of mantle derived orthogneiss and hybridsource derived leucogranites,a detailed geochemicalstudy has been conducted on granitoids which areexposed between the Shyok-Darbuk of the Pangongtranspressional zone.The Shyok-Darbuk is a complexzone,marked by migmatization,crustal anatexis,in-situemplacement of various granitoids within metapelitesand orthogneiss.Major and trace element data have beenused in this paper to classify the granitoids to estimatethe possible source regions and tectonic environment ofmagma generation and emplacement.展开更多
The albite rim is present in most felsic gneisses of the Fuping Complex. The presence of the rim indicates the coexistence of plagioclase and K-feldspar in the rock. The rim is formed immediately after the myrmekite, ...The albite rim is present in most felsic gneisses of the Fuping Complex. The presence of the rim indicates the coexistence of plagioclase and K-feldspar in the rock. The rim is formed immediately after the myrmekite, and both textures were derived from the alteration of K-feldspar. The difference is that that there is no quartz present in the rim, and the rim is nearly albite and the anorthite content of the rim plagioclase is substantially lower than that of the myrmekite plagioclase. Formed at 400- 500~C the albite rim was derived from the K-feldspar composition adjustment in the late or post- magmatism stage. As the temperature decreased, the equilibrium between K-feldspar and plagioclase could be maintained, and reactions between the minerals occurred. The leucocratic veins in the complex show distinguished magma or migmatitic characteristics. The rim might form in the late magma or deuteric stage. The formation of the rim implies obvious granitic magmaor melt-injection activity. Typical metamorphic rocks cannot produce the rims. Anatexis after medium-high grade metamorphism might be subordinate. If present, the anatexis is water-present, but the rim texture cannot be taken as the symbol of anatexis.展开更多
文摘The Paleoproterozoic boron deposits in east Liaoning occur in Mg-rich marble of Li’eryu Formation of Liaohe group. The mineralization was controlled by stratigraphic lithology. The volcano-sedimentation is the material base of ore- formation. Boron mainly derived from volcanic source. Boron in Li’ eryu formation was activated and transferred by mignati- zation and then deposited into ore when metasomatism occurrs in Mg-rich marble. Structural deformation reconstructed the boron ore bodies. Meanwhile, ore-bearing hydrothermal solution produced by structural deformation and remetasomated the host-ore rocks or filled in fissure of ore. Boron deposit is a stratabound deposit, which formed by mignatization and structu- ral deformation mineralization.
文摘Continental growth is episodic,and arc-continentalmargin has importance for the formation of continentalcrust in the Shyok Suture Zone(SSZ).To shed light onthe petrogenesis of mantle derived orthogneiss and hybridsource derived leucogranites,a detailed geochemicalstudy has been conducted on granitoids which areexposed between the Shyok-Darbuk of the Pangongtranspressional zone.The Shyok-Darbuk is a complexzone,marked by migmatization,crustal anatexis,in-situemplacement of various granitoids within metapelitesand orthogneiss.Major and trace element data have beenused in this paper to classify the granitoids to estimatethe possible source regions and tectonic environment ofmagma generation and emplacement.
基金supported by the China Geological Survey (nos. 1212011120129,1212010811033,and 1212011120152)the National Natural Science Foundation of China (no. 41072053)
文摘The albite rim is present in most felsic gneisses of the Fuping Complex. The presence of the rim indicates the coexistence of plagioclase and K-feldspar in the rock. The rim is formed immediately after the myrmekite, and both textures were derived from the alteration of K-feldspar. The difference is that that there is no quartz present in the rim, and the rim is nearly albite and the anorthite content of the rim plagioclase is substantially lower than that of the myrmekite plagioclase. Formed at 400- 500~C the albite rim was derived from the K-feldspar composition adjustment in the late or post- magmatism stage. As the temperature decreased, the equilibrium between K-feldspar and plagioclase could be maintained, and reactions between the minerals occurred. The leucocratic veins in the complex show distinguished magma or migmatitic characteristics. The rim might form in the late magma or deuteric stage. The formation of the rim implies obvious granitic magmaor melt-injection activity. Typical metamorphic rocks cannot produce the rims. Anatexis after medium-high grade metamorphism might be subordinate. If present, the anatexis is water-present, but the rim texture cannot be taken as the symbol of anatexis.
