反蛇纹石

反蛇纹石
反蛇纹石
	蛇纹岩中的反蛇纹石结晶，标本地点波兰
基本资料
类别	页硅酸盐矿物
化学式	(Mg, Fe)3Si2O5OH4
性质
晶系	单斜晶系

反蛇纹石（英语：Antigorite）是层状蛇纹石亚群之一种，属页硅酸盐矿物^[1]，其理想化学式为(Mg,Fe²⁺)₃Si₂O₅(OH)₄^[2]。它是蛇纹石的高压同质异形体，常见于变质蛇纹岩中。反蛇纹石及其蛇纹石同质异形体在俯冲带动力学中具有着重要作用，由于其相对脆弱和高含量的水（高达 13 ％）^[3] ^[4]. 它的学名是以意大利/瑞士边境地区的 Geisspfad 蛇纹岩 Valle Antigorio ^[5] 命名，通常用作珠宝和雕刻中的宝石。

地质产状

反蛇纹石是低温、高压（或高变形）产物，在伸展和挤压构造体系都有^[6]。蛇纹石在俯冲带的超基性绿片岩相中分布很多。出露到地球表面的蛇纹石也常见。含反蛇纹石的蛇纹岩通常具高度变形的纹理，表明它们形成的动态环境。反蛇纹石通常有伴生的磁铁矿、绿泥石和碳酸盐矿物^[7]。橄榄石在热液作用、低度变质作用和风化作用下亦能转变为反蛇纹石，在这种环境下，它常与滑石和碳酸盐伴生。

3Mg₃SiO₄ (橄榄石) + H₂O + SiO₂ → 2Mg₃Si₂O₅OH₄ (蛇纹石)
2Mg₃Si₂O₅OH₄ (蛇纹石) + CO₂ → 2Mg₃Si₄O₁₀OH₂ (滑石) + 3MgCO₃ (菱镁矿)+ H₂O ^[8]

物理性质

反蛇纹石的颜色通常是深绿色，但也可能是淡黄色、灰色、棕色或黑色。它的莫氏硬度为 3.5–4，光泽呈玻璃状至油腻状^[9]。蛇纹石的比重为 2.5-2.6。属单斜晶系并具云母状解理，这是页硅酸盐矿物的一个特性，并且难以融合^[10]。由反蛇纹石组成的蛇纹岩通常是糜棱岩。构成这些岩石的叶蛇纹石颗粒非常细（大约 1 到 10 微米）并且是纤维状的，这种岩石纹理是由于晶格优选取向引起的^[11]。

参考文献

^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
^ "AMCSD Search Results". rruff.geo.arizona.edu.
^ Dódony, István; Pósfai, Mihály; Buseck, Peter R. (2002). "Revised structure models for antigorite: An HRTEM study". American Mineralogist. 87 (10): 1443–1457. Bibcode:2002AmMin..87.1443D. doi:10.2138/am-2002-1022. ISSN 0003-004X. S2CID 55304426.
^ Ulmer, P.; Trommsdorff, V. (1995). "Serpentine Stability to Mantle Depths and Subduction-Related Magmatism". Science. 268 (5212): 858–861. Bibcode:1995Sci...268..858U. doi:10.1126/science.268.5212.858. ISSN 0036-8075. PMID 17792181. S2CID 12878042.
^ "Antigorite Mineral Data". webmineral.com.
^ Ribeiro Da Costa, Isabel; Barriga, Fernando J. A. S. Viti; Mellini, Marcello; Wicks, Frederick J. (2008). "Antigorite in deformed serpentinites from the Mid-Atlantic Ridge". European Journal of Mineralogy. 20 (4): 563–572. Bibcode:2008EJMin..20..563R. doi:10.1127/0935-1221/2008/0020-1808.
^ Ribeiro Da Costa, Isabel; Barriga, Fernando J. A. S. Viti; Mellini, Marcello; Wicks, Frederick J. (2008). "Antigorite in deformed serpentinites from the Mid-Atlantic Ridge". European Journal of Mineralogy. 20 (4): 563–572. Bibcode:2008EJMin..20..563R. doi:10.1127/0935-1221/2008/0020-1808.
^ Page 5 Deer, Howie, Zussman "An Introduction to the Rock Forming Minerals" ISBN 0 582 44210 9
^ "Antigorite Mineral Data". webmineral.com.
^ "Antigorite gemstone information". www.gemdat.org.
^ Horn, Charis; Bouilhol, Pierre; Skemer, Philip (2020). "Serpentinization, Deformation, and Seismic Anisotropy in the Subduction Mantle Wedge". Geochemistry, Geophysics, Geosystems. 21 (4). Bibcode:2020GGG....2108950H. doi:10.1029/2020GC008950. ISSN 1525-2027.

[”1”-1] Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.

[”2”-2] "AMCSD Search Results". rruff.geo.arizona.edu.

[”3”-3] Dódony, István; Pósfai, Mihály; Buseck, Peter R. (2002). "Revised structure models for antigorite: An HRTEM study". American Mineralogist. 87 (10): 1443–1457. Bibcode:2002AmMin..87.1443D. doi:10.2138/am-2002-1022. ISSN 0003-004X. S2CID 55304426.

[”4”-4] Ulmer, P.; Trommsdorff, V. (1995). "Serpentine Stability to Mantle Depths and Subduction-Related Magmatism". Science. 268 (5212): 858–861. Bibcode:1995Sci...268..858U. doi:10.1126/science.268.5212.858. ISSN 0036-8075. PMID 17792181. S2CID 12878042.

[”5”-5] "Antigorite Mineral Data". webmineral.com.

[”6”-6] Ribeiro Da Costa, Isabel; Barriga, Fernando J. A. S. Viti; Mellini, Marcello; Wicks, Frederick J. (2008). "Antigorite in deformed serpentinites from the Mid-Atlantic Ridge". European Journal of Mineralogy. 20 (4): 563–572. Bibcode:2008EJMin..20..563R. doi:10.1127/0935-1221/2008/0020-1808.

[”7”-7] Ribeiro Da Costa, Isabel; Barriga, Fernando J. A. S. Viti; Mellini, Marcello; Wicks, Frederick J. (2008). "Antigorite in deformed serpentinites from the Mid-Atlantic Ridge". European Journal of Mineralogy. 20 (4): 563–572. Bibcode:2008EJMin..20..563R. doi:10.1127/0935-1221/2008/0020-1808.

[”8”-8] Page 5 Deer, Howie, Zussman "An Introduction to the Rock Forming Minerals" ISBN 0 582 44210 9

[”9”-9] "Antigorite Mineral Data". webmineral.com.

[”10”-10] "Antigorite gemstone information". www.gemdat.org.

[”11”-11] Horn, Charis; Bouilhol, Pierre; Skemer, Philip (2020). "Serpentinization, Deformation, and Seismic Anisotropy in the Subduction Mantle Wedge". Geochemistry, Geophysics, Geosystems. 21 (4). Bibcode:2020GGG....2108950H. doi:10.1029/2020GC008950. ISSN 1525-2027.

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