A number of word-class gold deposits in the Kassan area in the west Kyrgyzstan are associated with the Andagul granitic intrusion. These gold deposits share similarities with the class of “intrusion-related gold deposits”, implying that the gold mineralization may be genetically related to the intrusion. In order to evaluate this potential relationship, it is important to study the petrogenesis of the intrusion. This study examines the sources and physiochemical conditions of crystallization of the Andagul intrusion and their implications for gold mineralization, through an integrated study involving zircon geochronology, mineral chemistry, whole-rock chemistry and isotopic geochemistry. The Andagul intrusion consists mainly of granodiorite, which is characterized by metaluminous and medium-K calc-alkaline compositions, very high Ba (>2000 ppm) and Sr (>1500 ppm) abundances, high LREE, LILE, low HFSE , right-inclined REE pattern with a flat HREE pattern, and insignificant Eu anomalies ((Eu/Eu*)N = 0.80 - 0.85). These geochemical characteristics, together with relatively low positive εNd(t) values (+2.1 to +4.2), moderately low (87Sr/86Sr)i ratios (0.70497 to 0.70666), relatively low initial Pb isotopic ratios ( (206Pb/204Pb)t = 17.642 to 18.398, (207Pb/204Pb)t = 15.599 to 15.618, and (208Pb/204Pb)t = 38.034 to 38.297), juvenile εHf(t) (+2.29 to +4.78) and relatively young model ages (T2DM(Hf)=1027 to 1180 Ma, T2DM(Nd)= 729 - 898 Ma) indicate that the magma was sourced from partial melting of juvenile basaltic lower crust with amphibole as dominant residual. The high Zr saturation temperatures (807oC to 825 oC), relatively high Mg# values (43-52) and presence of mafic enclaves, and development of acicular apatite and oscillatory plagioclases and titanite, suggest that the magmatism was related to injection of hot mantle material into the lower crust, which took place in a slab-break off setting at ca. 300 Ma. The high water contents (4.0 to 5.2 wt.% H2O) and moderately oxidized to weakly reduced state (ΔFMQ = -0.29 ~ +2.82) deduced from amphibole composition and zircon Ce anomaly are favorable for enrichment of gold in magmatic fluids.

The Tieshan Fe-Cu skarn deposit in the Daye district of eastern China provides a valuable opportunity to better understand the nature and genesis of hydrothermal REEs mineralization associated with calc-alkaline intermediate magmatism. This deposit is genetically associated with an intrusive complex locally called Tieshan pluton. The Tieshan complex consists of six intrusive bodies which are, from a temporal order, syenodiorite, gabbroic diorite, monzodiorite, granodiorite, and quartz diorite or monzodiorite. The geochemical signatures, combined with whole-rock Sr-Nd and zircon Hf isotopic results, suggest that the Tieshan intrusion was derived from an enriched mantle sources metasomatized by slab-derived fluids and/or melts (Li et al., 2009). The Tieshan deposit contains proven reserves of 160 Mt Fe at an average of 53 % (up to 70 %) and 0.67 Mt Cu at 0.58 % (up to 12 %) (Yao et al., 1993). Skarn assemblages are well developed throughout the ore zones and consist of diopside, garnet, scapolite, phlogopite, actinolite, chlorite, albite, plagioclase, tremolite, pargasite, and epidote, which are frequently overprinted by quartz, calcite, ankerite, anhydrite, and fluorite. Common metallic minerals are magnetite, hematite, chalcopyrite, bornite, marcasite, pyrrhotite, molybdenite, specularite, and siderite. Native gold or electrum is present as inclusions mainly in pyrite and chalcopyrite. Our recent drill-core logging has revealed extensive REEs mineralization closely associated with the skarn assemblages and iron ores. The REEs mineralization is spatially related to the gabbroic diorite of the Tieshan complex and mostly developed in the endoskarn zone dominated by diopside. Individual REEs ore zones are 7.9-12 m thick and average in REE2O3 contents at 1-13 %. REEs ores are variably associated with Fe or Fe-Cu skarn ores. The ore minerals are dominated by allanite with minor parasite and titanite. They typically occur as hydrothermal overprints on diopside, garnet, scapolite, and albite, are texturally intergrown with minor magnetite, hematite, apatite, chlorite, and epidote, and are locally overprinted by anhydrite, pyrite, chalcopyrite, and calcite. Allanite grains typically show oscillatory zoning and dissolution-reprecipitation textures that indicate at least four generations of allanite. The textural relations imply episodic REEs mineralization. Allanite, epidote, and diopside host abundant primary fluid inclusions that have homogenization temperatures of 500-670 ºC and calculated salinities of 40-60 wt% NaCl equiv., consistent with common presence of multiple daughter minerals dominated by halite and sylvite. Parasite is locally observed in a few inclusions. The fluid inclusion data thus demonstrate the REEs were transported by and precipitated from high-temperature saline to hyposaline magmatic fluids. The widespread scapolite and the very high salinity of the fluid inclusions led us to conclude that chlorine has been important in transporting REEs at Daye. The skarn formation involving interaction between the carbonate wallrocks and the magmatic-derived fluids would have enhanced the pH of the latter and consequently facilitated the precipitation of REEs minerals to form the ores. On the U-Pb Tera-Wasserburg diagram, titanite has lower-intercept age of 141 ± 1 Ma and a weighted mean206Pb/238U age of 140 ± 2 Ma, which are consistent with the zircon U-Pb age of the gabbroic diorite. This age consistency demonstrate a genetic relations between the REEs mineralization and the intermediate magmatism represented by the Daye pluton. We suggest that REEs were sourced from the magmas produced by partial melting of an enriched mantle source that have previously been metasomatised by slab-derived fluids and/or melts, a processes enriching the mantle peridotite by REEs, particularly light REEs in the case of Daye deposit.

The carbon budget in the Earth interior is currently not well constrained because the sample of the Earth’s core is unavailable. Several ways have been used to estimate the Earth’s carbon inventory but their results vary more than one order of magnitude. Recently, using isotope signals to solve this kind of budget problem becomes an alternative way for various different isotope systems (Satish-Kumar et al., 2011; Shahar et al., 2011; Moynier et al., 2011; Lazar et al., 2012; Horita and Polyakov, 2015; Shahar et al., 2016; Elardo and Shahar, 2017; Liu et al., 2017). Here equilibrium carbon isotope fractionation factors for almost all kinds of carbon-bearing species in the deep Earth are provided by using first-principles methods. For the first time, silicate melts and iron melts are calculated directly other than using their crystalline analogues in the previous studies. We find that melts have very different compressibility than those crystalline analogues. Besides, compared to a fixed crystalline structure, melts have numerous local different configurations. A reasonable simulation of melts should considering the proper sampling of these local configurations to obtain a precise average result. Neglecting these differences between melts and crystalline analogues will let the estimations of isotope fractionation factors to be risky.In this study, we calculate the equilibrium isotopic fractionation factors of carbon between silicate melt, iron melt, magnesite, diamond, moissanite, and various iron-carbides at magma ocean conditions by first-principles density functional theory. The influences of pressure and redox condition on the chemical environment and isotope fractionation of carbon are also carefully investigated. The average value of δ13C of BSE is estimated to be about −7.2‰, according to the mantle derived diamonds (Cartigny et al., 2014). Although many people thought this signal can represent the carbon isotope composition of the whole mantle, we disagree with it. Diamonds can only represent the major C-bearing species at upper part of mantle, but not the major C-bearing species at lower mantle. Higher temperatures can destabilize diamond. Based on the mantle derived diamonds’ δ13C signal (−7.2‰) and those isotope fractionation factors we provided, we can deduce out the signal for the BSE. Our new carbon isotope fractionation results cannot compromise the mantle-core differentiation scenario at magma ocean period, no matter it is an equilibrium or a Rayleigh distillation process. However, if most of carbon was delivered from one or several giant impacts from the accretion feeding zone of Mars (i.e., with the similar chemistry), and with 2 times of the current mass of Mars to be delivered to the proto-Earth, all discrepancies will be resolved perfectly. This scenario coincides with the giant impact hypothesis of the Moon formation and the unexpected small size of Mars. Finally the carbon content of Earth’s core is estimated about 0.2wt% of the core. Carbon is not a major light element in the Earth's core.

I talk here keynote speech on geochemistry of hot springs in relation to the first co-sponsorship between Geochemical Society of Japan and Hot Spring Society of Japan. I present historical geochemical study of hot springs, geochemical features of volcanic hot springs, non-volcanic hot springs and deep wells. Radioactive springs containing radium and radon are distributed in non-volcanic hot springs. σ-diagram reveals hot spring waters originate from meteoric water with various influences of fossil seawater and magmatic water associated with supercritical water in the deep underground. Hydrothermal environments including hot springs are interested in the origin and evolution of life in the early earth, and probably played important role on the survive of photosynthetic organisms and eukaryotes in the snowball earth of 730-700 Ma and 665-635 Ma. Further organic geochemical studies on various biomarkers of molecular level isotope ratios in the hydrothermal environments including various hot springs such as Kuroyu Onsen.

Although no fumarolic activity on Mt. Iwoyama of Kirishima volcanic complex has been observed since 2007(Funasaki et al., 2017), new fumaroles have appeared in December 2015.In this study, chemical composition and the stable isotopic ratio of hydrogen and oxygen of thermal waters around Mt. Iwoyama of Kirishima volcanic complex were analyzed and their origin and water quality changes associated with volcanic activity were investigated. Most of them were classified as acid sulfate water and were considered to be originated through the mixing of meteoric water with volcanic fluid basically, but a water collected near the fumarolic area on the summit of Mt. Iwoyama has high chloride concentration and δD and δ¹⁸O values. The changes in water quality and δD and δ¹⁸O values associated with volcanic activity were also recognized.

The author proposes to use hot-spring water for one of the disaster measures in big cities. A drinking water shortage is possible one of big concerning in case of big earthquake such as Nankai/Tounankai earthquake. We should prepare engine pump for public bath and hotels to use their water for citizens.

Subducted slab contains two types of water; pore water (H2O) and mineral-bounded water (OH). The former has been expelled at shallow depth and the latter has released by decomposition of OH-bearing mineral at elevated temperature and pressure. Jarrard (2003) and Hacker (2008) has revealed the water budget of the subduction zones of the earth. We interpret the water circulation model of the two subduction zones; SW-Japan and NE-Japan arcs where distinctive differences on the fluid circulations are found between the two. And we show the areal distribution of the slab fluid mixed into groundwater using Li-Cl-Br indicator. And we try to show the consistency of the observational areal variation of slab fluid upwelling and the water circulation models.

The ubiquitous occurrence of sedimentary-pore-fluid-like halogens and noble gases in metamorphic rocks from the Sanbagawa belt is best explained by a model where water with a pore-fluid signature is incorporated into subducting oceanic lithosphere as serpentine along fracture zones developed at the outer rise and released to the mantle wedge associated with the serpentine dehydration without significant modification in the halogen and noble gas compositions.

We present recent progress in Marine Geochemistry using stable isotopes as tracers.

Trace elements in the ocean have become essential means and objects in modern oceanography as trace nutrients for marine organisms, tracers for modern ocean, and proxies for paleoceanography. International research programme GEOTRACES launched in 2000s is going to release the second Intermediate Data Product (IDP2017) this August. We have developed a multielemental analytical method for trace elements in seawater, which significantly contributed to produce reliable data in this programme. I will report major points of our analytical method and results of field observations.

Trace elements in the ocean show a vertical distribution that sharply reflects various material circulation processes and is very useful for elucidation of material circulation.Bismuth, which is a trace element, can be expected as an important tracer of marine material circulation occurring on a relatively short time scale because the residence time in the ocean is as short as about 20 years (Lee et al., 1985/1986). However, Bi concentration in open ocean water is extremely low and it is difficult to precisely quantify it, and the number of reported worldwide is poor. Therefore, in this research, using the already established analysis method (Norisuye & Sohrin, 2012), our purpose is elucidate the concentration distribution of dissolved Bi in the Western Pacific Ocean sampled by Hakuho Maru KH-14-6 cruise, KH-11-7 cruise and Shinsei Maru KS-13-T3 cruise. At the station in the western North Pacific, it showed a remarkable concentration maximum in the subsurface layer of the North Pacific subtropical mode water (NPSTMW). It was found that Bi concentration of each layer in the southern hemisphere stations is lower than that in the northern hemisphere. This study is the first in the data of the Southern Hemisphere.

140°04’10.0"E)試料中のモリブデン，タングステンの濃度ならびに同位体比を分析した．これらの結果から，日本海における過去45000年の酸化還元環境を推定し，その古海洋プロクシとしての可能性を議論する"

Introduction Trace metals such as Fe, Cu, and Zn are essential micronutrients for bacteria and phytoplankton in the ocean. These trace metals interact with organic ligands and form organic-metal complexes, which reduces the bioavailable fractions (Bruland et al., 1991). It is therefore important to clarify the chemical species of the trace metals and their biogeochemical cycles in the ocean. However, little information is available on the distributions of dissolved trace metals and those chemical speciation in the hydrothermal system, which show quite different chemical compositions with ambient seawater (Von Damm et al., 1985). In this study, distributions of trace metals (Mn, Fe, Cu and Zn) and Zn chemical speciation were determined to investigate the geochemical processes of trace metals in the Tachibana Bay, where active hydrothermal activity was reported at the coastal area.Methods Seawater samples were collected in the Tachibana Bay, Nagasaki Prefecture by using acid-cleaned X-type Niskin samplers during TS Kakuyo-maru cruise (May 2012). All of seawater samples were filtered with capsule filters (<0.2μm, Acropak). After fltration, sulfide in seawater was determined onboard by using CSV. Samples for the dissolved trace metal concentration were acidified to pH<1.8 with ultra pure HCl and samples for Zn speciation were frozen immediately onboard the ship. On a land-based laboratory, dissolved trace metal concentrations were determined by using ICP-MS. Additionally, dissolved Cu and Zn concentrations were determined by using CSV and compared with those by ICP-MS. For the Zn speciation, ligand concentrations (CL) and conditional stability constants (K′ZnL) were obtained from a titration using competitive ligand equilibrium / adsorptive cathodic stripping voltammetry (van den Berg, 1985).Results and Discussion In the Tachibana Bay, high sulfide concentration (60 nM) was observed at the bottom of the coastal area, reflecting active hydrothermal system. Dissolved Cu and Zn were sharply decreased at the bottom of the coastal area, whereas dissolved Mn and Fe were increased. Also, relatively high total ligand concentration for Zn (CL) was calculated near the bottom. We found relatively high dissolved Zn concentrations with the ICP-MS compared with CSV, while dissolved Cu concentrations were generally similar. Difference in dissolved Zn concentrations between ICP-MS and CSV methods may suggest the presence of nanoparticulate Zn sulfide in the dissolved phase, which is electrochemically inert. The biogeochemical cycling of trace metals in the Tachibana Bay is considerably affected by hydrothermal system.