Studies on budget of organic matter in mantle and crust of arc during subduction and magmatism

本研究的目的和目标是基于EPMA、CNS、FT-JR、Py-GC、Py-GC/MS和天然岩石稳定碳同位素分析，以及高P-T条件下天然玻璃+ H_2O +碳氢化合物实验，了解弧系俯冲、吸积和岩浆活动过程中地壳和楔幔挥发性组分的行为和平衡。研究结果总结如下：1) s型花岗岩中的碳质物质来源于花岗岩岩浆与周围泥质岩石的相互作用。花岗闪长岩矿物中的颗粒状碳质物质含有长脂肪烃键、含氧有机物和芳香碎片。这些有机群在长石、石英和黑云母中的分布不同。结果表明：(1)大部分有机质是在泥质岩石部分熔融过程中释放出来的，(2)少量有机质被困在高粘性的长英质熔体中，在不同氧化条件下花岗岩岩浆冷却和结晶过程中被聚合。2)荷罗曼橄榄岩块体和高镁安山岩的橄榄石和辉石中含有B、N、Cl等碳质物质。在荷罗曼橄榄岩块中，从尖晶石、斜长石、辉沸石和直辉石的热解块状岩石中，检测到含Cl和N、N - c_8烷烃和N - c_8烷烃的芳香族化合物。从高镁安山岩的热解块状岩石中发现了甲苯和萘等芳香族化合物。非碳酸盐碳的δ ^<13>C值为：辉橄榄岩：-25.5‰vs PDB，辉橄榄岩：-23.4‰，灰橄榄岩：-21.9‰和-28.0‰。这些结果表明，霍罗曼橄榄岩块体和HMA岩浆受到流体的影响，这些流体可能来源于楔状地幔中的俯冲板块。3)对中地壳条件下长英质岩浆及其凝固过程中沉积烃的转化进行了初步研究。起始原料和条件为：花岗岩玻璃+烃类[正己烷和正四己烷]+ h2o；5 kb、900℃。结果表明，所有实验产物中均存在残余碳质物质，不仅以碳酸盐和石墨的形式存在，而且以固态烃的形式存在，表明发生了聚合反应。少

The purpose and targets of the project are the understanding of the behavior and budget of volatile components an the crust and wedge mantle during subduction, accretion and magmatism in arc systems based on EPMA, CNS, FT-JR, Py-GC, Py-GC/MS and stable carbon isotopes analyses for natural rocks, and experiments using natural glass + H_2O + hydrocarbon under high P-T conditions.The results of researches are summarized as follows ;1)Carbonaceous matter in S-type granitoids was derived from interaction between granitoid magmas and surrounding pelitic rocks. Particulate carbonaceous materials in minerals in the granodiorite contain long-aliphatic hydrocarbon bonds, oxygen-bearing organic compounds, and aromatic fragments. The distribution of these organic groups differs between feldspar, quartz and biotite. We conclud that (a) most organic matter is released from the system during partial melting of pelitic rocks, however, (b) a small amount is trapped in highly viscous felsic melt and pol … More ymerized during cooling and crystallization of granitoid magma under differing oxidation conditions.2) Carbonaceous matter including B, N and Cl was found in olivine and pyroxene from the Horoman Peridotite Mass and high-Mg andesite. Aromatic compounds with Cl and N, n-C_8 alkane and n-C_<8-12> alkane were detected from pyrolyzed bulk rocks of spinel and plagioclase lherzolite, and harzburgite in the Horoman Peridotite Mass. Aromatic compounds such as toluene and naphthalene were found from pyrolyzed bulk rocks of high-Mg andesite. δ ^<13>C values of non-carbonate carbon are lherzolite : -25.5‰ vs PDB, harzburgite : -23.4‰, and dunite : -21.9‰ and -28.0‰. These results indicate that the Horoman Peridotite Mass and HMA magma were influenced by fluid, which was probably derived from subducted slab, in wedge mantle.3)Preliminary experiments were carried out to examine transformation of sediment -derived hydrocarbons in felsic magma and during its solidification at middle crustal condition. Starting materials and conditions were : granitic glass + hydrocarbon [n-hexane and n-tetracosane] + H_2O ; 5kb, 900℃. Results showed that remnant carbonaceous materials remained in all experimental products, not only as carbonate and graphite but also as solid state hydrocarbon, indicating that polymerization occurred. Less