Chemical compositions of garnet and clinopyroxene and their genetic significances in Yemaquan skarn iron–copper–zinc deposit, Qimantagh, eastern Kunlun

Garnet composition as an indicator of skarn formation: LA‐ICP‐MS and EPMA studies on oscillatory zoned garnets from the Haobugao skarn deposit, Inner Mongolia, China

“…Most of the oscillatory zoned garnets in the Haobugao skarn deposit are homogeneous and contain no corresponding bell‐shaped chemical zoning as described in previous studies (Ismail et al, ; Peng et al, ; Zuo et al, ). The Grt IA, for example, are characterized by abundance of oscillatory zoning under optical microscope but are generally chemically homogeneous and have no compositional zoning.…”

“…All the EPMA analysis data are presented in Supporting Information Table S1, and endmember compose of garnets is shown in Figure 5 in the form of ternary plot. Parts of the interesting EPMA data are shown in Figure 6 in the form of line graphs, and the corresponding analysed positions are marked by red line in Figure 3 Most of the oscillatory zoned garnets in the Haobugao skarn deposit are homogeneous and contain no corresponding bell-shaped chemical zoning as described in previous studies (Ismail et al, 2014;Peng et al, 2015;Zuo et al, 2015). The Grt IA, for example, are characterized by abundance of oscillatory zoning under optical microscope but are generally chemically homogeneous and have no compositional zoning.…”

“…Garnet/pyroxene ratios are usually used to determine the oxidationstate of hydrothermal fluids in skarn deposits (Baghban, Hosseinzadeh, Moayyed, Mokhtari, & Gregory, 2015;Meinert, 1997;Meinert, Hedenquist, Satoh, & Matsuhisa, 2003;Zhai et al, 2014;Zuo et al, 2015). The oxidized skarn would preferentially contain andradite garnet (contains Fe 3+ ) and diopside, whereas it tends to contain grossular garnet and hedenbergite clinopyroxene (contain Fe 2+ ) in reduced conditions (Einaudi & Burt, 1982;Zuo et al, 2015). The question is that which factor primarily controlled the endmember contents of garnet in the Haobugao deposit, the wall rock specimen, the hydrothermal fluid composition, or the ore-forming condition (oxygen fugacity)?…”

“…As a geochemical tracer, garnet in metamorphic and magmatic systems is usually characterized by HRE-enriched and LREE-depleted REE pattern (Bai & van Groos, 1999;Chen, Zhou, Zheng, Chen, & Hu, 2015;Dragovic, Samanta, Baxter, & Selverstone, 2012;Yang et al, 2013) and high Lu/Hf and Sm/Nd ratios (Hensen & Zhou, 1995;Smit, Scherer, & Mezger, 2013). Garnet is also a common mineral in skarntype deposits (Baghban et al, 2016;Meinert, 1992;Peng et al, 2015;Zhai et al, 2014) and is generally composed of andradite-grossular solid solution series, displaying variable REE patterns (Gaspar, Knaack, Meinert, & Moretti, 2008;Ismail et al, 2014;Zuo et al, 2015). Garnet in skarn-type deposits is generally precipitated during the prograde stage and is typically spatially related to magmatic intrusions Somarin, 2004).…”

LA-ICP-MS Analysis of Clinopyroxenes in Basaltic Pyroclastic Rocks from the Xisha Islands, Northwestern South China Sea

“…Relative to other minerals in mafic-ultramafic rocks, clinopyroxene is considered to be the main carrier for most trace elements and holds a unique further record of magma history [33,34]. The mineral chemistry of relict clinopyroxene in igneous rocks can reflect the characteristics of the primary magma well and has been widely used to study the nature of the original magma and complicated processes that have affected the lithospheric mantle [21,[35][36][37][38][39][40][41][42]. Furthermore, clinopyroxenes in altered basalts are of interest, because they often survive in a relatively pristine form, after the matrix and other minerals have been converted to secondary minerals.…”