On the Influence of Sea Surface Height Variability on Satellite Altimeter Derived Gravity

The effect of sea surface height (SSH) variability is one of the primary factors that limit the accuracy and resolution of altimeter-derived gravity values. We propose a method to estimate the influence of variation of the sea surface height on the accuracy of satellite-derived gravity by simulation technique, with a case study around Indonesian waters. Wederived an Indonesian marine gravity map using the Geosat-geodetic mission (GM). Since most of the area studied is located around coastal and shallow areas, the measurement of SSH of this area is less accurate. To obtain a distribution of SSH variability over the study area, Topex/Poseidon (T/P) data were first processed and assessed. Processing 52 cycles of the Topex/Poseidon data, the root mean square (RMS) of SSH variability for each cycle was found to vary from 1 to 179 cm. Further, for the purpose of estimating the accuracy of altimeter-derived gravity, we derived several levels of Gaussian noise, computed simulation data by adding the Gaussian noise to Geosat data, and determined simulated gravity maps. Based on the distribution of RMS values from T/P data and standard deviation (STD) differences between the simulated and the original gravity maps, we estimated the accuracy of the gravity map. Around Indonesian waters, the accuracy of the gravity map influenced by SSH variation was estimated to be within the range 0.8~93 mgal.     

Variance Component Estimation in Linear Inverse Ill-posed Models

Regularization has been applied by implicitly assuming that the weight matrix of measurements is known. If measurements are assumed to be heteroscedastic with different unknown variance components, all regularization techniques may not be proper to apply, unless techniques of variance component estimation are directly implemented. Although variance component estimation techniques have been proposed to simultaneously estimate the variance components and provide a means of regularization, the regularization parameter is treated as if it were also an extra variance component. In this paper, we assume no prior information on the model parameters and do not treat the regularization parameter as an extra variance component. Instead, we first analyze the biases of estimated variance components due to the regularization parameter and then propose bias-corrected variance component estimators. The results have shown that they work very well. Finally, we propose and investigate through simulations an iterative scheme to simultaneously estimate the variance components and the regularization parameter, in order to eliminate the effect of regularization parameter on variance components and the effect of incorrect prior weights or initial variance components on the regularization parameter.     

Geochemical Features of Vein Anhydrite from the Kakkonda Geothermal System, Northeast Japan

Abstract. Cathodoluminescence (CL) color, rare earth element (REE) content, sulfur and oxygen isotopes and fluid inclusions of anhydrite, which frequently filled in hydrothermal veins in the Kakkonda geothermal system, were investigated to elucidate the spatial, temporal and genetical evolution of fluids in the deep reservoir. The anhydrite samples studied are classified into four types based on CL colors and REE contents: type-N (no color), type-G (green color), type-T (tan color) and type-S (tan color with a high REE content). In the shallow reservoir, only type-N anhydrite is observed. In the deep reservoir, type-G anhydrite occurs in vertical veins whereas type-T and -N in lateral veins. Type-S anhydrite occurs in the heat-source Kakkonda Granite. The CL textures revealed that type-G anhydrite deposited earlier than type-T in the deep reservoir, implying that fracture system was changed from predominantly vertical to lateral.
Studies of fluid inclusions and δ³⁴S and δ¹⁸O values of the samples indicate that type-N anhydrite deposited from diluted fluids derived from meteoric water, whereas type-G, -T and -S anhydrites deposited from magmatic brines derived from the Kakkonda Granite with the exception of some of type-G with recrystallization texture and no primary fluid inclusion, which deposited from fossil seawater preserved in the sedimentary rocks. Type-G, -T and -S anhydrites exhibit remarkably different chondrite-normalized REE patterns with a positive Eu anomaly, with a convex shape (peak at Sm or Eu) and with a negative Eu anomaly, respectively. The difference in the patterns might result from the different extent of hydrothermal alteration of the reservoir rocks and contribution of the magmatic fluids.     

Benthic ecosystem development in an artificial tidal flat constructed from dredged spoil

Dredged spoil (DS) was used as a silt and clay additive in the construction of artificial tidal flats from mountain sand (MS). As the ratio of DS in the sediment media increased, the number of emerging macrobenthos increased. The composition of the macrobenthic community was also affected by the addition of DS, and the changes might be dependent on the ratio of DS to MS. In addition, the macrobenthos in the artificial tidal flats was more abundant than that in the control tidal flat, which was constructed with natural tidal flat sediment. With a silt and clay content of 25%, polychaetes Ceratonereis erythraeensis and Capitella sp. and the gastropod Batillaria cumingii were dominant, whereas no bivalves were present. With less silt and clay (5% and 10%), the bivalves Ruditapes philippinarum and Musculista senhousia were observed in the artificial flats, while their numbers in the control tidal flat were lower.     

Simultaneous Analysis of Natural Free Estrogens and Their Conjugates in Wastewater by GC‐MS

A solid‐phase extraction (SPE)‐gas chromatography (GC)‐mass spectrometry (MS) analytical method was developed for the simultaneous analysis of natural free estrogens and their conjugates in wastewater samples. Natural free estrogens and their conjugates in wastewater were successfully separated by the oasis hydrophilic‐lipophilic balance solid phase extraction (Oasis HLB SPE) method, and the conjugates were initially enzyme hydrolyzed by β‐glucuronidase or arylsulfatase from Helix pomatia prior to derivatization. N‐methyl‐N‐(tert‐butyldimethylsilyl)trifluoroacetamide (MTBSTFA) plus 1% tert‐butyldimetheylchlorosilane (TBDMCS) was chosen as the derivatization reagent, and the most appropriate conditions of derivatization were determined to be at 95°C for 90 min. The recovery ratios of nine target chemicals were determined by spiking them in 1 L of ultra‐purified water or the influent of a wastewater treatment plant (WWTP). The recovery ratios of six out of nine for the analytes ranged from 73.3–114.9% with relative standard deviations (RSD) from 1.6–19.9%. The established method was successfully applied to environmental wastewater samples which were collected from one municipal wastewater treatment plant (WWTP) in Osaka, Japan, for the determination of natural free estrogens and their conjugates. In the influent sample, E1, E2, E1‐3S, E3‐3S, and E1‐3G were detected at concentrations of 16.6, 9.6, 8.2, 21.9, and 3.2 ng L^–1, respectively. However, only E1 was detected at a high concentration of 44 ng L^–1 in the effluent sample, suggesting that it is the dominant natural free estrogen in the effluent.     

Low energy neutral atom imaging on the Moon with the SARA instrument aboard Chandrayaan-1 mission

This paper reports on the Sub-keV Atom Reflecting Analyzer (SARA) experiment that will be flown on the first Indian lunar mission Chandrayaan-1. The SARA is a low energy neutral atom (LENA) imaging mass spectrometer, which will perform remote sensing of the lunar surface via detection of neutral atoms in the energy range from 10 eV to 3 keV from a 100km polar orbit. In this report we present the basic design of the SARA experiment and discuss various scientific issues that will be addressed. The SARA instrument consists of three major subsystems: a LENA sensor (CENA), a solar wind monitor (SWIM), and a digital processing unit (DPU). SARA will be used to image the solar wind-surface interaction to study primarily the surface composition and surface magnetic anomalies and associated mini-magnetospheres. Studies of lunar exosphere sources and space weathering on the Moon will also be attempted. SARA is the first LENA imaging mass spectrometer of its kind to be flown on a space mission. A replica of SARA is planned to fly to Mercury onboard the BepiColombo mission.     

Experimental Constraints on the Thermal Peak of a Granulite from McIntyre Island, Enderby Land, East Antarctica

High-pressure experiments have been carried out at 11-22 kbar and 900-1200°C using a piston cylinder apparatus to constrain the thermal peak condition of a granulite characterized by the mineral assemblage of orthopyroxene+sillimanite+quartz from McIntyre Island, Enderby Land, East Antarctica. The bulk composition of the starting material is 85 wt.% McIntyre granulite+15 wt.% sillimanite. At 11 kbar, orthopyroxene, sillimanite and quartz are stable below 1000°C. At 1050°C sillimanite does not appear, and sapphirine coexists with orthopyroxene and quartz. These experimental results indicate that the McIntyre granulite has undergone the ultra high-temperature metamorphism at 1000-1050°C represented by the diagnostic mineral assemblage of orthopyroxene, sillimanite and quartz.     

Geology and K-Ar Ages of the South, Huh Bulgiin Hundii, Saran Uul, Taats Gol and Han Uul deposits in the Bayankhongor Region, Mongolia

Abstract: The Bayankhongor region in central Mongolia consists of a Paleozoic subduction system including Precambrian microcontinents (Baidrag and Burd Gol zones), obducted ophiolites and accretionary sedimentary rocks (Bayankhongor and Dzag zones), and forearc sedimentary rocks (Khangay zone). Arc magmatism in the Bayankhongor region is characterized by dominance of Early Paleozoic ilmenite-series and Late Paleozoic magnetite-series granitoids. These granitoids accompany many hydrothermal deposits of such various types as porphyry, skarn and vein. K-Ar dating on four deposits in the region revealed that the South porphyry Cu-Au, Huh Bulgiin Hundii skarn Cu-Au, Han Uul shear zone-hosted Au and Taats Gol pegmatite W-Au deposits formed at 240±5 Ma, 252±5 Ma, 283±6 Ma and 329±7 Ma, respectively.
Thus the former three are related to the Permian to earliest Triassic magnetite-series granitoids, whereas the W-Au pegmatite at Taats Gol to the Early Carboniferous ilmenite-series granitoids. Porphyry and skarn Cu-Au mineralization occurred at latest Permian to earliest Triassic, when the Andean-type arc magmatism was immediately followed by the collision between the Baidrag and Tarbagatai microcontinents.     

Mixed-water and hydrothermal dolomitization of the Pliocene Shirahama Limestone, Izu Peninsula, central Japan

The early Pliocene Shirahama Limestone is a grainstone-packstone principally composed of fragments of algae, bryozoa, and echinoderm and subordinate volcanic rocks. The limestone was variously dolomitized and the regional distribution of dolomite is patchy. Dolomite occurs as isolated crystals filling pores, moulds, and solution vugs, and mosaic aggregates replacing bioclasts. Calcite occurs as rim and pore-filling sparry cements, and as calcareous skeletons. Isotopically, the dolomites are classified into a heavy oxygen group (?2 to ? 3.5%₀ PDB) and a light oxygen group (?5.5 to ? 7.5%₀ PDB). Calcite associated with heavy oxygen dolomite has δ¹⁸O of ? 6.5 to ?8.5%₀ PDB, whereas those associated with light oxygen dolomite have a wide range from ?7.5 to ?14%₀ PDB. Calcite in dolomite-free limestone has an oxygen isotopic composition of ?2 to ?8.5%₀ PDB. Textures, chemistry, and isotopic evidence indicate that heavy oxygen calcite formed in freshwater, and heavy oxygen dolomite in a meteoric-marine mixture of 10–30% seawater. Light oxygen calcite and dolomite precipitated from modified hydrothermal fluids at approximately 30–65°C. Petrographic features, and both isotopic and chemical evidence suggest that the Shirahama Limestone was exposed to freshwater soon after deposition. Subsequently blocky calcite precipitated (Stage I). The limestone was locally submerged in the meteoric-marine mixture due to gradual subsidence or eustatic movement. This led to the precipitation of heavy oxygen, zoned dolomite and dolospar (Stage II). Hydrothermal alterations occurred in the area a few Myr ago, and related hydrothermal fluids and mixed meteoric-hydrothermal waters caused dedolomitization of some zoned dolomite, partial dissolution of vuggy dolomite, precipitation of limpid dolomite and recrystallization of some earlier dolomites (Stage III). Zeolites were also precipitated from these fluids. Finally, the Shirahama Limestone was exposed again to freshwater and sparry calcite precipitated to plug some of the remaining pores (Stage IV).     

浙江东阳晚白垩世早期翼龙足迹

根据中国浙江东阳上白垩统金华组发现的4个翼龙足迹,建立翼龙一新的遗迹种：东阳翼龙足迹。它具有以下特征：手迹的第Ⅱ和第Ⅲ指夹角为29°,第Ⅰ指和第Ⅱ指的夹角为52°;足迹的长与宽的比率为0.17,除了翼龙足迹外,在同一层位中还发现有蜥脚类、鸟脚类、兽脚类、帯蹼和不具蹼的鸟类足迹。这些足迹化石的发现,为研究该地区的古生态环境及以后动物的骨骼化石,尤其是翼龙骨骼化石提供了重要依据。