I II 2 I 0.35 km 2 E- Pm NE20 W NE SE 40 ~60 Y -SN 10~20m 50 m II NNE [1,3,5] 4 I NE [1] 1 Fig. 1 Simplified geologic map of the Bais

Size: px

Start display at page:

Download "I II 2 I 0.35 km 2 E- Pm NE20 W NE SE 40 ~60 Y -SN 10~20m 50 m II NNE [1,3,5] 4 I NE [1] 1 Fig. 1 Simplified geologic map of the Bais"

芯党
7 years ago
Views:

1 Geology and Mineral Resources of South China Vol.28, No.2 Jun : (2012) ~ ~ w(nacl eq ) 11% ~15% 11.32%3.4%~7.7% 4.8% 0.95 ~ 1.00 g/cm ~ kpa - - Cu Fe Pb Zn - - P A - [1] H-O [1-7] 1 [1-2, 8] E- mail shanlianggongzuo@126.com E-W

2 I II 2 I 0.35 km 2 E- Pm NE20 W NE SE 40 ~60 Y -SN 10~20m 50 m II NNE [1,3,5] 4 I NE [1] 1 Fig. 1 Simplified geologic map of the Baishantang copper deposit in the Beishan area a 5- b γ α 15- δμ,βμ I I m 5.58 m 13 m 38 ~ ~ m [3] II -170 m I I -150 m -

3 [1-2,4,8] - [1, 4, 8] 0.84%-1.26% 1.36%~2.94% Zn1.12%- - Ag Co % [3] Fig. 2 Simplified geologic map of the Baishantang copper deposit

4 SME -1.KV EI 50 ev <5% HIC-6A 2.5 mm mm CuPb 1.2 ml/min 1.0 ml/min <5% H-O CuPbZn I II ~ 170 m ~ μm 14-5% ~ 30% - L 1 L 2 L 1 6 ~ 10 μm 14 I BST09 L2 2-6 μm μm I BST ~ ~ 260 B - BST08-9 B-BST ~170 II 120 ~ LinkamTH ~ 180 I <30 ±0.2 >30 1~5 DT ~ ~ ± ~ ~180 RG ~170

5 Fig. 3 Homogenization temperature histograms of fluid inclusions from Baishantang copper deposit

6 Table 1 Characteristics of fluid inclusions and representative microscopic temperature data in the copper-bearing quartz vein of the Baishantang copper deposit m BST07 II 3~6 BST08 II 4~6 BST-160M II 4~6 B-BST08-3 II 4~8 B-BST08-9 I 3~10 B-BST08-14 I 3~7 BST09 I 6~10! " #$! %& ( )*!! & ( + & ( #,- + $ + & ( #$ & ( % w(nacláâ) 8~ ~ ~ ~6.74 5~ ~ ~ ~ ~20 127~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ B-BST N B-BST I II B-BST B-BST B-BST B-BST α-β I 368 I B-BST08-10 II [9] 4 Fig. 4 Blowout graph of quartz and chalcopyrite in the Baishantang copper deposit

7 Table 2 Results of blowout temperature measured with quartz and chalcopyrite in the Baishantang copper deposit mg B-BST II / B-BST II / B-BST08-10 I / B-BST08-9 I / B-BST / B-BST % 160 ~170 w(nacl eq ) 3.4%~7.7% 4.8% Wikinson NaCl-H 2 O - - [11] ~1.00 g/cm g/cm 3 Bodnar 1.0 g/cm 3 [10] ~260 w(nacl eq ) Roedder NaCl-H 2 O P [12] 11% ~ 15% -T -D 5 NaCl- H 2 O - - [11] Fig. 5 Diagram showing homogenization temperaturesalinity- density relationship in the NaCl- H 2 O system of the Baishantang copper deposit 6 NaCl- H 2 O P- T- D [12] Fig. 6 P- T- D diagram of the NaCl- H 2 O system in Baishantang copper deposit

8 B-BST08-3 CH4 40 ~ ~ H 2 O CO 2 99% KPa H 2 O 3.8 Zk801-B6 CH 4 H 2 O 3 4 CO 2 N 2 C 2 H 6 H 2 S Ar [13] H 2 O CH 4 CO 2 CH 4 N 2 C 2 H 6 H 2 S Ar N 2 C 2 H 6 He O 2 H 2 O-CO 2 -CH 4 -N 2 - B-BST08-9 CO 2 C 2 H 6 H 2 S C 2 H 6 3 mol% Table 3 Gas phase group composition in quartzs from Baishantang copper deposit (mol%) HÁO NÁAr* COÁCHÂCÁHÃHÁS B-BST08-9 I I B-BST08-3 I II Zk801-B * ClÁSOÂÃÁNaÄKÄMgÃÄCaÃÄ Table 4 Ion composition in quartzs from Baishantang copper deposit 10-6 B-BST08-9 I I B-BST08-3 I II SO 4 Cl - Na + Ca 2+ K + Mg SO 4 Na + Na + -Ca SO 4 -Cl - Na 2 SO 4 - CaSO 4 - NaCl-KCl 3.9 H-O I I II lnα - = /T 2 [14] ~500 7 I δd% II δd% δ 18 O% [15] 7 I H- O 7 Fig. 7 H- O isotope constitution of ore- forming fluid of No. I ore- body in Baishantang copper deposit

9 H-O Table 5 H-O isotope data of ore-forming fluid of No. I ore-body in Baishantang copper deposit DÁÂÃ( ) doáâ( ) doáâã( ) B-BST I II B-BST I II B-BST I I B-BST I I H- O CuFePbZn [16] Cu [1] AR2 4 PbZn CuFePbZn FeCu MoSn Bi W CuAu Ag Pb Zn 3 Ag Co Ni Mn [17] [18] - [19] Mankaya Lepanto [20-21] [22] Cu-Mo-Au CuPbZn Fig. 8 Sketch map showing distribution of hydrothermskarn - porphyry polymetallic deposits nearby Baishantang 9 area

10 CuPbZn Fig. 9 Cu- Pb- Zn combination anomalies nearby Baishantang copper deposit %~15% w(nacl eq) % w(nacl eq )3.4%~7.7% w (NaCl eq ) 4.8 % w(nacl eq ) 0.95~ [1],,,. 1 [M]. : [2],,, [J]., (4): [3],,,. [M]. : 1.00 g/cm ~ kpa [4]. [D]. : [5]. [J]., (2):1-17. [6]. [D]. : ( ) [7]. [J]., - - Cu (1-2): [8]. Rb- Sr [J]., (3): [9],. α- β 1.. [J]., (1): [10] Bodnar R J. Vised equation and stable for determining the 2,,. reezing point depression of H 2 0- NaCl solutions [J]. Geochimi Cosmochim.Acta : :20 [11] Wilkinson. J. J. Fluid inclusions in hydrothermal ore de posits [J].Lithos, : [12] Roedder E. Fluid inclusions as samples of ore fluids, In: Geochemistry of Hydrothermal Ore Deposits [J]. Barnes H L (ed.) John Wiley & Sons, New York, [13].

11 [D]. : [14] Clayton R N, O Neil J R and Mayeda T K.Oxygen isotope exchange between quartz and water [J]. Journal of Geophysical Research: Solid Earth, (17): [15] Taylor HP Jr. The application of oxygen and hydrogen isotope studies to problems of hydrothermal alteration and ore deposition [J]. Econ. Geol., : (18): [16],,,. [21] Hedenquist J W, Arrbas A and Reynolds T J. Evolution of an [J]., (6): Intrusion- Centered Hydrothermal System: Far Southeast- Lepanto Porphyry and Epithermal Cu- Au deposits, [17],,. - Philippines [J]. Economic geology, (4) [J]. - [22],,,. (), (2): [J]., (2): [18],,,. [19],,. - [J]., (2): [20] Hedenquist J W, Lowenstern J B. The role of magmas in the formation of hydrothermal ore deposits [J]. Nature, [M]. : Geological Features and Ore-Forming Fluid of Baishantang Copper Deposit in Beishan Area, Gansu Province SHAN Liang 1, ZHENG You-ye 2, XU Rong-ke 2, ZHANG Yu-lian 3, CAO Liang 4 (1. Development Research Center of China Geological Survey, Beijing ; 2. Faculty of Earth Resourses, China University of Geosciences, Wuhan ;3. Xi an Center of China Geological Survey, Xi an ; 4. Wuhan Geology Survey Center of China Geological Survey, Wuhan ) Abstract: The Beishan area in Gansu province is one of the most important metallogenic belts in China, with abundant mineral resources. Previous studies revealed that the porphyry copper deposit is the main metallogenic type in this area as represented by the Baishantang copper deposit, whereas there are rare studies on ore-forming fluid in this deposit. This work made a further study on geological characteristics of the deposit and its fluid inclusions. The results show that the fluid inclusions have simple shape, are mostly of gasliquid two-phase type, medium to low temperature (230 ~ 260 and 160 ~ 170 of homogenization temperature in the ore bearing quartz veins and 301 of cracking temperature with chalcopyrite concomitant), low salinity (11% ~ 15% w(nacl eq ), averaged 11.32% w(nacl eq ); 3.4% ~ 7.7% w(nacl eq ), averaged 4.8% w (NaCl eq )), moderate density (about 0.95 ~ 1.00 g/cm 3 ) and medium to low press (about ~ kpa). The deposit shows exothermal to epithermal vein type characteristics. Combined with geology feature and the series of hydrothermal vein-type, skarn-type, also porphyry-type Cu-Fe-Pb-Zn deposits distributed annularly center on the Shibanquan monzonitic granite surrounding nearby the Baishantang area, it is suggested that Baishantang copper deposit is the mineralization type of exothermal to epithermal vein type. It is the product to late stage of magmatic hydrothermal system evolution. There is some connection existed among the mineralization series surrounding Shibanquan monzonitic granite. Key words: porphyry copper deposit; ore-forming fluid; Baishantang Cu deposit, Beishan area

164 2011 年 Fig.1 图 1 [2] 湘东北地区黄金洞金矿地质图 Geological map of Huangjindong gold deposit, Northeastern Hunan Province 1. 白垩系 ;2. 二叠 - 泥盆系 ;

164 2011 年 Fig.1 图 1 [2] 湘东北地区黄金洞金矿地质图 Geological map of Huangjindong gold deposit, Northeastern Hunan Province 1. 白垩系 ;2. 二叠 - 泥盆系 ; 第 27 卷第 2 期 2011 年 6 月 Geology and Mineral Resources of South China Vol.27, No.2 June, 2011 文章编号 : 1007-3701(2011)02-0163-006 湖南黄金洞金矿成矿流体包特征李杰, 陈必河 1, 安江华 1, 谭仕敏 1, 张孝国 2 1,