Through analysis of geological characteristics of the gold deposit,the shape,occurrence,and spatial distribution of ore-controlling fault plane in the Shanhou mining area were investigated,and the regularities of enri...Through analysis of geological characteristics of the gold deposit,the shape,occurrence,and spatial distribution of ore-controlling fault plane in the Shanhou mining area were investigated,and the regularities of enrichment and emplacement of ore body were summarized. The analysis shows that the Shanhou gold deposit was controlled by NE-NNE Zhaoping fault zone; the fault gouge developed in fault zone provides a barrier to ore-bearing hydrothermal solution,and the industrial ore body is all distributed within 40 m of footwall of main fault plane. The industrial ore body is mainly enriched in the NE positions of fault where the deep dips changed to flat dips,and shows the obvious regularity of NE lateral trending with angle around 75°. The stress analysis of fault in mineralization epoch showed that the ore-controlling structure presented the characteristics of righthanded rotation inverse-fault activity in mineralization epoch,and the host space tended to occur in NE regional tension positions where the dips become flat in the strike of fault,causing emplacement of ore body. It is thought by combining equal interval distribution of deposit with spatial variation of industrial ore body and orecontrolling fault structure that the Shanhou gold deposit recurred in regularity and the non-ore interval occurred in the ore body. Meanwhile,it is predicted that the favorable target area of prospecting lies in the areas of deep main fault plane with NE strike( > 30°) and the deep dips changing to flat dips in the Shanhou mining area,and the prospecting should be emphasized. The favorable deep mineralization prospect exists in middle Beibo mining area,where is the key area for future prospecting.展开更多
Emplacement P-T condition estimations using granites are important for understanding metamorphic and erosional processes of orogenic belt.Granites are widespread in South China and a majority of them are peraluminous....Emplacement P-T condition estimations using granites are important for understanding metamorphic and erosional processes of orogenic belt.Granites are widespread in South China and a majority of them are peraluminous.Particularly,over 91%of the Indosinian granites exposed in the region are peraluminous in composition.It is extremely hard to determine the pressure of intrusion of these peraluminous granites due to the absence of amphibole,a good mineral barometer commonly identified in metaluminous granites.Muscovite is a common mineral in peraluminous granites,certain kind of it could be used as a mineral barometer to constrain the emplacement pressure of peraluminous granites.In this paper,results of petrographic and geochemical studies of muscovites from the Indosinian and early Yanshanian two-mica granites at the Longyuanba in the eastern Nanling Range are reported.Based on petrographic studies,the primary muscovite can be discriminated from the secondary muscovites.Muscovites from the Indosinian two-mica granites are enriched in Ti,Al,Mg,and Na,and depleted in Fe and Mn.Geochemically,these muscovites were considered as primary,whereas those from the Yanshanian two-mica granites fall into the area of secondary muscovite on discrimination diagrams.Barometer estimations show that pressures calculated for primary muscovites are accurate,but those calculated for secondary muscovites are overestimated.The average pressure of emplacement of the Longyuanba Indosinian two-mica granites is 5.9 kbar,corresponding to^19 km in depth,suggesting that the Indosinian granitic magmas were probably generated by partial melting of a thickened crust root in a compressional tectonic setting.展开更多
基金Project of Shanhou Gold Deposit of Laixi of Shandong Province(SDLX2012-3-28)
文摘Through analysis of geological characteristics of the gold deposit,the shape,occurrence,and spatial distribution of ore-controlling fault plane in the Shanhou mining area were investigated,and the regularities of enrichment and emplacement of ore body were summarized. The analysis shows that the Shanhou gold deposit was controlled by NE-NNE Zhaoping fault zone; the fault gouge developed in fault zone provides a barrier to ore-bearing hydrothermal solution,and the industrial ore body is all distributed within 40 m of footwall of main fault plane. The industrial ore body is mainly enriched in the NE positions of fault where the deep dips changed to flat dips,and shows the obvious regularity of NE lateral trending with angle around 75°. The stress analysis of fault in mineralization epoch showed that the ore-controlling structure presented the characteristics of righthanded rotation inverse-fault activity in mineralization epoch,and the host space tended to occur in NE regional tension positions where the dips become flat in the strike of fault,causing emplacement of ore body. It is thought by combining equal interval distribution of deposit with spatial variation of industrial ore body and orecontrolling fault structure that the Shanhou gold deposit recurred in regularity and the non-ore interval occurred in the ore body. Meanwhile,it is predicted that the favorable target area of prospecting lies in the areas of deep main fault plane with NE strike( > 30°) and the deep dips changing to flat dips in the Shanhou mining area,and the prospecting should be emphasized. The favorable deep mineralization prospect exists in middle Beibo mining area,where is the key area for future prospecting.
基金supported by the Chinese Academy of Sciences(Grant Nos.KZCX1-YW-15-2&GIGCAS-135-Y234151001)National Natural Science Foundation of China(Grant Nos.41173039 and 40973025)
文摘Emplacement P-T condition estimations using granites are important for understanding metamorphic and erosional processes of orogenic belt.Granites are widespread in South China and a majority of them are peraluminous.Particularly,over 91%of the Indosinian granites exposed in the region are peraluminous in composition.It is extremely hard to determine the pressure of intrusion of these peraluminous granites due to the absence of amphibole,a good mineral barometer commonly identified in metaluminous granites.Muscovite is a common mineral in peraluminous granites,certain kind of it could be used as a mineral barometer to constrain the emplacement pressure of peraluminous granites.In this paper,results of petrographic and geochemical studies of muscovites from the Indosinian and early Yanshanian two-mica granites at the Longyuanba in the eastern Nanling Range are reported.Based on petrographic studies,the primary muscovite can be discriminated from the secondary muscovites.Muscovites from the Indosinian two-mica granites are enriched in Ti,Al,Mg,and Na,and depleted in Fe and Mn.Geochemically,these muscovites were considered as primary,whereas those from the Yanshanian two-mica granites fall into the area of secondary muscovite on discrimination diagrams.Barometer estimations show that pressures calculated for primary muscovites are accurate,but those calculated for secondary muscovites are overestimated.The average pressure of emplacement of the Longyuanba Indosinian two-mica granites is 5.9 kbar,corresponding to^19 km in depth,suggesting that the Indosinian granitic magmas were probably generated by partial melting of a thickened crust root in a compressional tectonic setting.
