Numerical Modeling of Mineral Precipitation in Seafloor Hydrothermal Circulation
-
摘要: 为了探索高渗透性洋壳中高温热液循环系统的形成机制，以数值模拟为手段研究热液循环中的矿物沉淀过程及其对洋壳渗透率的反馈.在热液对流-矿物反应模型中考虑了硬石膏、黄铁矿和黄铜矿的沉淀和溶解反应，基于矿物的溶度积计算矿物的沉淀/溶解量，并将其转换为渗透率的变化.结果显示，黄铁矿和黄铜矿分布于350~380℃等温线范围内，并随着热液温度升高而逐渐向海底推移.海水被加热及与热液混合过程中沉淀出硬石膏，在热液上升通道两侧形成低渗透性的烟囱状结构，降低了海水-热液混合程度从而使热液温度升高.高温热液通道建立后，便会有更多的金属物质随着高温热液被运输至浅层洋壳或海底.模拟结果为理解海底高温热液喷口的形成机制提供了借鉴.Abstract: To understand the mechanism of high-temperature hydrothermal system in highly permeable oceanic crust, a reactive hydrothermal convection model is proposed to solve mineral precipitation and its feedback on permeability. Mineral reaction of anhydrite, pyrite and chalcopyrite are accounted in the model. Precipitation and dissolution can be solved using solubility product of the mineral and transformed into permeability change. The results suggest that pyrite and chalcopyrite are precipitated as cap-like structure around 300-380℃ isotherm. With hydrothermal temperature increasing, the cap-like structure is moving to seafloor. Anhydrite is precipitated as chimney-like structure around focus flow by seawater heating and seawater-hydrothermal mixing. The low permeable chimney-like structure prevent seawater-hydrothermal mixing and thus keep hydrothermal at high temperature. Once the high-temperature focusing flow is formed, more metal can be dissolved in hydrothermal and be transported to shallow crust and seafloor. The numerical simulation results could help to understand the mechanism of high-temperature hydrothermal venting.
-
图 1 溶度积和矿物沉淀量（质量分数）随温度的变化
a.硬石膏；b.黄铁矿；c.黄铜矿. 黑色点划线表示海水（Ca2+、SO42-含量分别为10、28 mmol/kg）的Ca2+和SO42-浓度乘积随温度的变化（图a），热液（Fe、S、Cu含量分别为20、5.9、0.035 mmol/kg）中的离子浓度乘积随温度的变化（图b、c）
Fig. 1. Solubility product and precipitation mass fraction as function of temperature.
图 2 热液流动-矿物沉淀数值模拟计算流程图
Fig. 2. Flow chart of main algorithm for the reactive transport model
图 4 不同渗透率的参考模型
图a、b分别表示t=3 000 a时kext为10-14 m2、4×10-14 m2的流体温度分布，图c表示喷口温度和物质流动速率随渗透率的变化
Fig. 4. Fluid temperature of reference model with different permeabilities
图 5 流体温度、矿物沉淀量和地壳渗透率演化
矿物沉淀量用饱和度表示，比如硬石膏饱和度0.6表示60%的孔隙被硬石膏填充，从而降低了渗透率.第一行图中灰色带箭头的曲线表示流体流动的流线分布
Fig. 5. Evolution of fluid temperature, saturation of mineral and crustal permeability
图 6 不同kext的模型在考虑化学反应和不考虑化学反应情况下的喷口流体温度演化曲线
Fig. 6. Vent temperature evolution of models with different kext, with and without reaction
图 7 不同kext的模型的物质通量分析
Qdis表示出流的物质通量, Qre表示入流的物质通量；物质通量负值表示入流，正值表示出流.z为深度（m）.纵轴表示沿着剖面不同位置处的物质通量占总物质通量的百分比，中央的热液集中上升区域的物质通量较两侧大
Fig. 7. Mass flux analysis of models with different kext
图 9 两种Cu浓度边界条件模型的硬石膏、黄铁矿和黄铜矿分布(t=1 600 a)
Fig. 9. Anhydrite, pyrite and chalcopyrite distribution of models with different (CCu) boundary conditions (t=1 600 a)
表 1 二维热液对流-矿物反应模型边界条件
Table 1. Boundary conditions of 2D reactive hydrothermal convection model
变量 底部边界 顶部边界 侧壁边界 T 450 ℃ 流入：5 ℃；流出：零梯度 零梯度 v 无流出 自由流入或流出 无流出 p 物质流动速率Qin = 11.5 g/(m∙s) 30 MPa 零梯度 CCa2+ 100 10 零通量 CSO42- 0 28 零通量 CFe 20 0 零通量 CS 5.9 0 零通量 CCu 0.035 0 零通量 注：离子浓度边界条件值参考 Hannington et al.(2016) 和Kawada and Yoshida(2010)，单位为mmol/kg.
下载: 导出CSV
-
[1] Andersen, C. , Rüpke, L. , Hasenclever, J. , et al. , 2015. Fault Geometry and Permeability Contrast Control Vent Temperatures at the Logatchev 1 Hydrothermal Field, Mid-Atlantic Ridge. Geology, 43(1): 51-54. https://doi.org/10.1130/g36113.1 [2] Barreyre, T. , Olive, J. A. , Crone, T. J. , et al. , 2018. Depth-Dependent Permeability and Heat Output at Basalt-Hosted Hydrothermal Systems across Mid-Ocean Ridge Spreading Rates. Geochemistry, Geophysics, Geosystems, 19(4): 1259-1281. https://doi.org/10.1002/2017gc007152 [3] Becker, K. , Fisher, A. T. , 2000. Permeability of Upper Oceanic Basement on the Eastern Flank of the Juan de Fuca Ridge Determined with Drill-String Packer Experiments. Journal of Geophysical Research: Solid Earth, 105(B1): 897-912. https://doi.org/10.1029/1999jb900250 [4] Coumou, D. , Driesner, T. , Heinrich, C. A. , 2008. The Structure and Dynamics of Mid-Ocean Ridge Hydrothermal Systems. Science, 321(5897): 1825-1828. https://doi.org/10.1126/science.1159582 [5] Driesner, T. , 2010. The Interplay of Permeability and Fluid Properties as a First Order Control of Heat Transport, Venting Temperatures and Venting Salinities at Mid-Ocean Ridge Hydrothermal Systems. Geofluids, 10: 132-141. https://doi.org/10.1111/j.1468-8123.2009.00273.x [6] Elderfield, H. , Schultz, A. , 1996. Mid-Ocean Ridge Hydrothermal Fluxes and the Chemical Composition of the Ocean. Annual Review of Earth and Planetary Sciences, 24(1): 191-224. https://doi.org/10.1146/annurev.earth.24.1.191 [7] Fontaine, F. J. , Cannat, M. , Escartin, J. , et al. , 2014. Along-Axis Hydrothermal Flow at the Axis of Slow Spreading Mid-Ocean Ridges: Insights from Numerical Models of the Lucky Strike Vent Field (MAR). Geochemistry, Geophysics, Geosystems, 15(7): 2918-2931. https://doi.org/10.1002/2014gc005372 [8] Fontaine, F. J. , Rabinowicz, M. , Boulègue, J. , 2001. Permeability Changes Due to Mineral Diagenesis in Fractured Crust: Implications for Hydrothermal Circulation at Mid-Ocean Ridges. Earth and Planetary Science Letters, 184(2): 407-425. https://doi.org/10.1016/s0012-821x(00)00332-0 [9] German, C. R., Seyfried, J. W. E., 2014. Hydrothermal Processes. In: Schubert, G., ed., Treatise on Geochemistry. Elsevier, Amsterdam. 191-233. https://doi.org/10.1016/b978-0-08-095975-7.00607-0 [10] Guo, Q. H. , Liu, M. L. , Li, J. X. , 2017. Thioarsenic Species in the High-Temperature Hot Springs from the Rehai Geothermal Field (Tengchong) and Their Geochemical Geneses. Earth Science, 42(2): 286-297(in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-DQKX201702010.htm [11] Hannington, M. , Harðardóttir, V. , Garbe-Schönberg, D. , et al. , 2016. Gold Enrichment in Active Geothermal Systems by Accumulating Colloidal Suspensions. Nature Geoscience, 9(4): 299-302. https://doi.org/10.1038/ngeo2661 [12] Hannington, M. D., de Ronde, C. E. J., Petersen, S., 2005. Sea-Floor Tectonics and Submarine Hydrothermal Systems. In: Hedenquist, J. W., Thompson, J. F. H., Goldfarb, R. J., eds., Economic Geology 100th Anniversary Volume. Society of Economic Geologists. https://doi.org/10.5382/av100.06 [13] Hannington, M. D., Galley, A. G., Herzig, P. M., et al., 1998. Comparison of the TAG Mound and Stockwork Complex with Cyprus-Type, Massive Sulfide Deposits. In: Herzig, P. M., Humphris, S. E., Miller, D. J., eds., Proceedings of the Ocean Drilling Program. Ocean Drilling Program, Texas. https://doi.org/10.2973/odp.proc.sr.158.217.1998 [14] Hasenclever, J. , Theissen-Krah, S. , Rüpke, L. H. , et al. , 2014. Hybrid Shallow On-Axis and Deep Off-Axis Hydrothermal Circulation at Fast-Spreading Ridges. Nature, 508(7497): 508-512. https://doi.org/10.1038/nature13174 [15] Ingebritsen, S. E. , Geiger, S. , Hurwitz, S. , et al. , 2010. Numerical Simulation of Magmatic Hydrothermal Systems. Reviews of Geophysics, 48(1): RG1002. https://doi.org/10.1029/2009rg000287 [16] Ingebritsen, S. E. , Manning, C. E. , 2010. Permeability of the Continental Crust: Dynamic Variations Inferred from Seismicity and Metamorphism. Geofluids, 10(1-2): 193-205. https://doi.org/10.1111/j.1468-8123.2010.00278.x [17] Jupp, T. , Schultz, A. , 2000. A Thermodynamic Explanation for Black Smoker Temperatures. Nature, 403(6772): 880-883. https://doi.org/10.1038/35002552 [18] Kawada, Y. , Yoshida, S. , 2010. Formation of a Hydrothermal Reservoir Due to Anhydrite Precipitation in an Arc Volcano Hydrothermal System. Journal of Geophysical Research: Solid Earth, 115(B11): B11106. https://doi.org/10.1029/2010jb007708 [19] Kulik, D. A. , Wagner, T. , Dmytrieva, S. V. , et al. , 2013. GEM-Selektor Geochemical Modeling Package: Revised Algorithm and GEMS3K Numerical Kernel for Coupled Simulation Codes. Computational Geosciences, 17(1): 1-24. https://doi.org/10.1007/s10596-012-9310-6 [20] Li, H. M. , Zhai, S. K. , Yu, Z. H. , 2008. Fluid Evolution Model of the Atlantic TAG Hydrothermal Activity Area. Scientia Sinica Terrae, 38(9): 1136-1145(in Chinese). [21] Li, J. , Sun, Z. L. , Huang, W. , et al. , 2014. Modern Seafloor Hydrothermal Processes and Mineralization. Earth Science, 39(3): 312-324(in Chinese with English abstract). http://gateway.proquest.com/openurl?res_dat=xri:pqm&ctx_ver=Z39.88-2004&rfr_id=info:xri/sid:baidu&rft_val_fmt=info:ofi/fmt:kev:mtx:article&genre=article&jtitle=Earth%20Science&atitle=Modern%20Seafloor%20Hydrothermal%20Processes%20and%20Mineralization [22] Li, J. X. , Guo, Q. H. , Yu, Z. Y. , 2017. Impact of Clay Mineral Formation in High-Temperature Geothermal System on Accuracy of Na-K and K-Mg Geothermometers. Earth Science, 42(1): 142-154(in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTotal-DQKX201701012.htm [23] Liu, K. J. , Huang, F. , Gao, S. , et al. , 2018. Characteristics and Research Significance of Polymorphic Pyrite in Logatchev Hydrothermal Area, North Atlantic. Earth Science, 43(5): 1562-1573(in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTotal-DQKX201805018.htm [24] Lowell, R. P. , Farough, A. , Germanovich, L. N. , et al. , 2012. A Vent-Field-Scale Model of the East Pacific Rise 9°50'N Magma-Hydrothermal System. Oceanography, 25(1): 158-167. https://doi.org/10.5670/oceanog.2012.13 [25] Lowell, R. P. , Farough, A. , Hoover, J. , et al. , 2013. Characteristics of Magma-Driven Hydrothermal Systems at Oceanic Spreading Centers. Geochemistry, Geophysics, Geosystems, 14(6): 1756-1770. https://doi.org/10.1002/ggge.20109 [26] Lowell, R. P. , Gosnell, S. , Yang, Y. , 2007. Numerical Simulations of Single-Pass Hydrothermal Convection at Mid-Ocean Ridges: Effects of the Extrusive Layer and Temperature-Dependent Permeability. Geochemistry, Geophysics, Geosystems, 8(10): Q10011. https://doi.org/10.1029/2007gc001653 [27] Lowell, R. P. , Yao, Y. F. , Germanovich, L. N. , 2003. Anhydrite Precipitation and the Relationship between Focused and Diffuse Flow in Seafloor Hydrothermal Systems. Journal of Geophysical Research: Solid Earth, 108(B9): 2424. https://doi.org/10.1029/2002jb002371 [28] Mezon, C. , Mourzenko, V. V. , Thovert, J. F. , et al. , 2018. Thermal Convection in Three-Dimensional Fractured Porous Media. Physical Review E, 97(1): 013106. https://doi.org/10.1103/physreve.97.013106 [29] Pierre, S. , Gysi, A. P. , Monecke, T. , 2018. Fluid Chemistry of Mid-Ocean Ridge Hydrothermal Vents: A Comparison between Numerical Modeling and Vent Geochemical Data. Geofluids, 1-20. https://doi.org/10.1155/2018/1389379 [30] Sleep, N. H. , 1991. Hydrothermal Circulation, Anhydrite Precipitation, and Thermal Structure at Ridge Axes. Journal of Geophysical Research: Solid Earth, 96(B2): 2375-2387. https://doi.org/10.1029/90jb02335 [31] Syverson, D. D. , Scheuermann, P. , Higgins, J. A. , et al. , 2018. Experimental Partitioning of Ca Isotopes and Sr into Anhydrite: Consequences for the Cycling of Ca and Sr in Subseafloor Mid-Ocean Ridge Hydrothermal Systems. Geochimica et Cosmochimica Acta, 236: 160-178. https://doi.org/10.1016/j.gca.2018.03.018 [32] Tao, C. H. , Lin, J. , Guo, S. Q. , et al. , 2012. First Active Hydrothermal Vents on an Ultraslow-Spreading Center: Southwest Indian Ridge. Geology, 40(1): 47-50. https://doi.org/10.1130/g32389.1 [33] Tivey, M. K. , 2007. Generation of Seafloor Hydrothermal Vent Fluids and Associated Mineral Deposits. Oceanography, 20(1): 50-65. https://doi.org/10.5670/oceanog.2007.80 [34] Tivey, M. K. , Humphris, S. E. , Thompson, G. , et al. , 1995. Deducing Patterns of Fluid Flow and Mixing within the TAG Active Hydrothermal Mound Using Mineralogical and Geochemical Data. Journal of Geophysical Research: Solid Earth, 100(B7): 12527-12555. https://doi.org/10.1029/95jb00610 [35] Tivey, M. K. , McDuff, R. E. , 1990. Mineral Precipitation in the Walls of Black Smoker Chimneys: A Quantitative Model of Transport and Chemical Reaction. Journal of Geophysical Research: Solid Earth, 95(B8): 12617-12637. https://doi.org/10.1029/jb095ib08p12617 [36] Wagner, W. , Pruß, A. , 2002. The IAPWS Formulation 1995 for the Thermodynamic Properties of Ordinary Water Substance for General and Scientific Use. Journal of Physical and Chemical Reference Data, 31(2): 387-535. https://doi.org/10.1063/1.1461829 [37] Wang, S. J. , Zhai, S. K. , Yu, Z. H. , et al. , 2018. Reflections on Model of Modern Seafloor Hydrothermal System. Earth Science, 43(3): 835-850(in Chinese with English abstract). http://www.researchgate.net/publication/325084055_Reflections_on_Model_of_Modern_Seafloor_Hydrothermal_System [38] Weis, P. , Driesner, T. , Heinrich, C. A. , 2012. Porphyry-Copper Ore Shells Form at Stable Pressure-Temperature Fronts within Dynamic Fluid Plumes. Science, 338(6114): 1613-1616. https://doi.org/10.1126/science.1225009 [39] Xi, Z. Z. , Li, R. X. , Song, G. , et al. , 2016. Electrical Structure of Sea-Floor Hydrothermal Sulfide Deposits. Earth Science, 41(8): 1395-1401(in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-DQKX201608011.htm [40] Xu, T. F. , Sonnenthal, E. , Spycher, N. , et al. , 2006. TOUGHREACT-A Simulation Program for Non-Isothermal Multiphase Reactive Geochemical Transport in Variably Saturated Geologic Media: Applications to Geothermal Injectivity and CO2 Geological Sequestration. Computers & Geosciences, 32(2): 145-165. https://doi.org/10.1016/j.cageo.2005.06.014 [41] Yapparova, A. , Gabellone, T. , Whitaker, F. , et al. , 2017. Reactive Transport Modelling of Dolomitisation Using the New CSMP++GEM Coupled Code: Governing Equations, Solution Method and Benchmarking Results. Transport in Porous Media, 117(3): 385-413. https://doi.org/10.1007/s11242-017-0839-7 [42] Yu, X. , Chu, F. Y. , Dong, Y. H. , et al. , 2013. Detachment Fault and Oceanic Core Complex: A New Mode of Seafloor Spreading. Earth Science, 38(5): 995-1004(in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-DQKX201305011.htm [43] Zhao, X. F. , Li, Z. K. , Zhao, S. R. , et al. , 2019. Early Cretaceous Regional-Scale Magmatic-Hydrothermal Metallogenic System at the Southern Margin of the North China Carton. Earth Science, 44(1): 52-68(in Chinese with English abstract). http://www.researchgate.net/publication/332034266_Early_Cretaceous_Regional-Scale_Magmatic-Hydrothermal_Metallogenic_System_at_the_Southern_Margin_of_the_North_China_Carton [44] 郭清海, 刘明亮, 李洁祥, 2017. 腾冲热海地热田高温热泉中的硫代砷化物及其地球化学成因. 地球科学, 42(2): 286-297. doi: 10.3799/dqkx.2017.021 [45] 李怀明, 翟世奎, 于增慧, 2008. 大西洋TAG热液活动区流体演化模式. 中国科学: 地球科学, 38(9): 1136-1145. https://www.cnki.com.cn/Article/CJFDTOTAL-JDXK200809010.htm [46] 李军, 孙治雷, 黄威, 等, 2014. 现代海底热液过程及成矿. 地球科学, 39(3): 312-324. doi: 10.3799/dqkx.2014.030 [47] 李洁祥, 郭清海, 余正艳, 2017. 高温地热系统中粘土矿物形成对Na-K和K-Mg地球化学温标准确性的影响. 地球科学, 42(1): 142-154. doi: 10.3799/dqkx.2017.011 [48] 刘开君, 黄菲, 高尚, 等, 2018. 北大西洋Logatchev热液区多形貌黄铁矿特征及其意义. 地球科学, 43(5): 1562-1573. doi: 10.3799/dqkx.2018.414 [49] 王淑杰, 翟世奎, 于增慧, 等, 2018. 关于现代海底热液活动系统模式的思考. 地球科学, 43(3): 835-850. doi: 10.3799/dqkx.2018.907 [50] 席振铢, 李瑞雪, 宋刚, 等, 2016. 深海热液金属硫化物矿电性结构. 地球科学, 41(8): 1395-1401. doi: 10.3799/dqkx.2016.110 [51] 余星, 初凤友, 董彦辉, 等, 2013. 拆离断层与大洋核杂岩: 一种新的海底扩张模式. 地球科学, 38(5): 995-1004. doi: 10.3799/dqkx.2013.097 [52] 赵新福, 李占轲, 赵少瑞, 等, 2019. 华北克拉通南缘早白垩世区域大规模岩浆-热液成矿系统. 地球科学, 44(1): 52-68. doi: 10.3799/dqkx.2018.372 -
点击查看大图
图(9) / 表(1)
计量
- 文章访问数: 618
- HTML全文浏览量: 233
- PDF下载量: 55
- 被引次数: 0
