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摘要:
最新区域地质调查发现,西藏工布江达县松多乡存在天然非金属矿—黑曜岩。该矿源地处青藏高原冈底斯板块上,发育于新生代年波组中。"球泡"状黑曜石清晰可见,部分达到宝石级别。初步研究显示,该黑曜岩是地壳部分熔融的产物。冈底斯成矿带上成矿种类以多金属为主,松多黑曜岩的发现不仅初步圈定了一个非金属矿点,还为区域后续找矿工作和考古学研究提供了重要线索。
Abstract:During the recent regional geological survey, a nonmetallic ore source—obsidian was found in the Sumdo area of Jongbo Gyamda County, Tibet. The obsidian source originated from the Cenozoic Nianbo Formation in the Gangdise terrane. The bulb structures are clearly visible, and some obsidian stones have reached the gem level. A preliminary study was undertaken and the result reveals that the obsidian was derived from partial melting of the crust. Although the polymetallic ore deposits are common in the Gangdise metallogenic belt, the discovery of Sumdo obsidian has not only delineated a nonmetallic ore spot but also provided important clues for regional follow-up prospecting work and archaeological study.
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Key words:
- Tibet /
- Sumdo /
- Nianbo Formation /
- nonmetallic ore /
- obsidian
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表 1 西藏松多地区黑曜岩样品主量、微量和稀土元素分析结果
Table 1. Major, trace and rare earth element compositions of the obsidian in the Sumdo area, Tibet
样品号 S17T43H1 S17T43H2 S17T43H3 S17T43H4 S17T43H5 S17T43H6 S17T43H7 S17T43H8 SiO2 70.50 68.83 68.90 69.68 70.05 71.24 70.21 69.24 TiO2 0.11 0.13 0.13 0.12 0.12 0.12 0.12 0.13 Al2O3 13.59 14.58 14.82 14.70 13.37 12.69 13.71 14.37 Fe2O3T 0.71 0.79 0.79 0.76 0.81 0.73 0.78 0.78 MnO 0.05 0.06 0.06 0.06 0.06 0.06 0.06 0.06 MgO 0.31 0.12 0.13 0.18 0.25 0.11 0.12 0.12 CaO 0.96 1.11 0.79 0.66 1.01 0.79 0.71 0.83 Na2O 4.57 5.06 5.01 4.91 4.98 4.96 5.19 5.03 K2O 4.23 4.60 4.70 4.15 4.65 3.83 4.37 4.24 P2O5 0.02 0.01 0.02 0.02 0.02 0.01 0.02 0.02 烧失量 4.36 4.15 4.09 4.18 4.09 4.85 4.13 4.61 Li 32.66 18.19 19.68 33.28 23.88 36.68 29.58 38.68 P 93.56 75.08 82.13 78.02 77.20 79.54 57.00 56.74 Sc 1.67 1.37 1.48 1.67 1.87 1.67 1.64 1.54 Ti 670.80 668.00 685.94 660.60 662.60 679.80 677.80 634.40 V 3.93 4.28 3.94 3.81 4.37 4.10 4.84 5.36 Cr 2.52 1.06 2.88 8.80 2.83 1.90 1.94 1.14 Co 0.33 0.31 0.31 0.76 0.38 0.31 0.29 0.28 Ni 1.79 0.72 1.42 10.06 2.98 1.02 0.78 0.58 Cu 1.33 1.31 1.49 1.55 1.39 1.47 1.18 1.19 Zn 38.94 36.32 40.13 39.42 37.84 40.32 36.52 34.94 Ga 17.22 15.95 16.76 16.89 16.63 16.95 16.31 15.48 Rb 182.52 167.16 191.38 156.26 173.72 164.74 168.46 162.60 Sr 123.46 101.01 134.47 106.11 124.07 110.29 112.90 116.34 Y 8.09 6.65 7.50 7.77 8.39 8.18 8.23 8.08 Zr 95.20 93.48 98.25 106.08 110.42 112.31 107.51 116.25 Nb 9.67 9.58 9.87 9.87 9.43 9.84 9.84 9.37 Cs 10.77 9.98 14.88 9.55 10.46 9.28 10.00 9.55 Ba 1085.70 1057.98 1065.43 1086.14 1147.74 1075.58 1125.08 1116.50 La 31.26 27.58 29.57 29.80 32.24 30.32 32.28 32.26 Ce 62.98 59.00 61.80 59.22 65.44 60.86 63.10 65.76 Pr 6.27 5.47 5.90 6.05 6.54 6.17 6.51 6.51 Nd 19.75 17.11 18.47 19.18 20.66 19.52 20.92 21.14 Sm 2.96 2.54 2.75 2.89 3.10 2.96 3.18 3.17 Eu 0.45 0.38 0.43 0.45 0.47 0.45 0.48 0.48 Gd 1.97 1.66 1.83 1.94 2.06 1.97 2.13 2.13 Tb 0.24 0.20 0.22 0.24 0.25 0.24 0.26 0.26 Dy 1.34 1.14 1.27 1.37 1.45 1.39 1.50 1.50 Ho 0.26 0.22 0.24 0.26 0.28 0.27 0.29 0.29 Er 0.73 0.61 0.68 0.74 0.79 0.75 0.81 0.81 Tm 0.12 0.10 0.11 0.12 0.13 0.12 0.13 0.13 Yb 0.82 0.68 0.76 0.83 0.88 0.84 0.90 0.90 Lu 0.13 0.11 0.12 0.13 0.14 0.13 0.15 0.14 Hf 2.40 2.37 2.47 2.52 2.56 2.54 2.68 2.83 Ta 0.59 0.59 0.61 0.63 0.61 0.62 0.67 0.66 Pb 58.13 57.07 59.54 61.20 67.87 59.02 64.20 63.77 Th 26.97 25.48 26.55 27.37 29.33 27.50 30.32 31.00 U 6.85 6.80 6.99 7.32 7.31 7.10 7.78 7.80 注:主量元素含量单位为%,微量和稀土元素含量为10-6 -
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