Primary Ore Mineral Assemblage and Fluid Inclusion Study of the Batu Hijau Porphyry Cu-Au Deposit, Sumbawa, Indonesia

Abstract. The Batu Hijau porphyry Cu‐Au deposit, Sumbawa Island, Indonesia, is associated with a tonalitic intrusive complex. The temperature‐pressure condition of mineralization at the Batu Hijau deposit is discussed on the basis of fluid inclusion microthermometry. Then, the initial Cu‐Fe sulfide mineral assemblage is discussed. Bornite and chalcopyrite are major copper ore minerals associated with quartz veinlets. The quartz veinlets have been classified into ‘A’ veinlets associated with bornite, digenite, chalcocite and chalcopyrite, ‘B’ veinlets having chalcopyrite bornite along vuggy center‐line, rare ‘C’ chalcopyrite‐quartz veinlets, and late ‘D’ veinlets consisting of massive pyrite and quartz (Clode et al., 1999). Copper and gold mineralization is associated with abundant ‘A’ quartz veinlets. Abundant fluid inclusions are found in veinlet quartz consisting mainly of gas‐rich inclusions and polyphase inclusions throughout the veinlet types. The hydrothermal activity occurred in temperature‐pressure conditions of aqueous fluid immiscibility into hypersaline brine and dilute vapor. The halite dissolution (Tm[halite]) and liquid‐vapor homogenization (Th) temperatures of the polyphase inclusions in veinlet quartz range from 270 to 472d?C and from 280 to 454d?C, respectively. The estimated salinity ranges from 36 to 47 wt% (NaCl equiv.). The apparent pressures lower than 300 bars are estimated to have been along the liquid‐vapor‐halite curve for the fluid inclusions having the Th lower than the Tm that trapped the brine saturated with halite, or at slightly higher pressure relative to liquid‐vapor‐halite curve for the fluid inclusions having the Th higher than the Tm that trapped the brine unsaturated with halite. The actual temperature and pressure during the hydrothermal activity at the Batu Hijau deposit are estimated to have been around 300d?C and 50 bars. At such temperature‐pressure conditions, the principal and initial Cu‐Fe sulfide mineral assemblages are thought to be chalcopyrite + bornite solid solution (bnss) for the chalcopyrite‐bearing assemblage, and chalcocite‐digenite solid solution and bnss for the chalcopyrite‐free assemblage.     

Experimental study on the bidirectional inelastic deformation capacity of U‐shaped steel dampers for seismic isolated buildings

Hysteretic dampers are used to dissipate earthquake‐induced energy in base‐isolated structures by acquiring inelastic deformations, rendering their hysteretic behavior of vital importance. The present paper focuses on investigating the behavior of U‐shaped steel dampers under bidirectional loading; this is significantly different from their corresponding uniaxial behavior. Two main sets of loading tests on full‐scale specimens are conducted in this regard: (i) quasi‐static tests with simple histories and (ii) dynamic tests with realistic loading histories. Based on the results obtained in the quasi‐static tests, an interaction curve that accounts for the reduction of the cyclic deformation capacity is proposed. However, the fidelity of this relation must be assessed under loading conditions similar to those of a seismically isolated structure subjected to an earthquake, which represents the goal of the second set of tests. The results of the dynamic tests validate the proposed interaction curve for estimating the deformation capacity of U‐shaped steel dampers under bidirectional loading. Copyright © 2015 John Wiley & Sons, Ltd.     

Field survey of the East Java earthquake and tsunami of June 3, 1994

A field survey of the June 3, 1994 East Java earthquake tsunami was conducted within three weeks, and the distributions of the seismic intensities, tsunami heights, and human and house damages were surveyed. The seismic intensities on the south coasts of Java and Bali Islands were small for an earthquake with magnitudeM 7.6. The earthquake caused no land damage. About 40 minutes after the main shock, a huge tsunami attacked the coasts, several villages in East Java Province were damaged severely, and 223 persons perished. At Pancer Village about 70 percent of the houses were swept away and 121 persons were killed by the tsunami. The relationship between tsunami heights and distances from the source shows that the Hatori's tsunami magnitude wasm=3, which seems to be larger for the earthquake magnitude. But we should not consider this an extraordinary event because it was pointed out byHatori (1994) that the magnitudes of tsunamis in the Indonesia-Philippine region generally exceed 1–2 grade larger than those of other regions.     

Instruments, Detectors and the Future of Astronomy with Large Ground Based Telescopes

Results of a survey of instrumentation and detector systems, either currently deployed or planned for use at telescopes larger than 3.5 m, in ground based observatories world-wide, are presented. This survey revealed a number of instrumentation design trends at optical, near, and mid-infrared wavelengths. Some of the most prominent trends include the development of vastly larger optical detector systems (> 10⁹ pixels) than anything built to date, and the frequent use of mosaics of near-infrared detectors – something that was quite rare only a decade ago in astronomy. Some future science applications for detectors are then explored, in an attempt to build a bridge between current detectors and what will be needed to support the research ambitions of astronomers in the future.     

Disturbance of recruitment success of mantis shrimp in Tokyo Bay associated with effects of hypoxia on the early life history

We investigated effects of severe hypoxia (dissolved oxygen <1 ml l⁻¹) on recruitment of mantis shrimp Oratosquilla oratoria in Tokyo Bay. Ten-year field surveys were conducted to examine quantitative relationships in annual mean densities of larvae and juveniles, and spatial distribution of juveniles and severe hypoxia. There was no significant correlation between annual mean densities of larvae and juveniles, suggesting that mortality during larval or juvenile stages varies among years, which might have regulated abundance of young-of-the-year juveniles. Juvenile density was low in the severely hypoxic area, implying that hypoxia could affect survivals and spatial distribution of juveniles. Meanwhile, there are yearly fluctuations in juvenile density in normoxic areas of both northern and southern part of the bay. This evidence suggests that abundance of post-settled juveniles might have been determined by not only effects of hypoxia, but also other factors influencing mortality during the early life stages.     

Multivariate correlation analysis of suspended-sediment characteristics

Principal component analysis (PCA) was employed to investigate interrelationships among various characteristics of seawater and suspended sediments obtained from surface waters of two Asian marginal seas. On the basis of multivariate correlation analysis for the two marginal seas combined, three important factors were extracted and interpreted: (1) current-energy conditions, (2) the influence of rivers, and (3) biochemical conditions of seawater. A relationship between anisotropic mineral grains and combustible organic matter is suggested by the fact that suspended sediment, containing coarser anisotropic mineral grains, also contains larger amounts of combustible organic matter.     

Preservation of the shell matrix protein dermatopontin in 1500 year old land snail fossils from the Bonin islands

Organic molecules such as proteins can be preserved in certain fossils. The bulk properties of fossil proteins of both vertebrates and invertebrates have been studied for over half a century. Named proteins have so far been identified, however, only in vertebrate fossils, such as collagen from mammoth bones. Using immunological assays, we examined 1500 year old fossils of the extinct land snail Mandarina luhuana from the Bonin islands for the presence of dermatopontin, a molluscan shell matrix protein. First, we examined the shell microstructure and mineralogy of the fossil shells using scanning electron microscopy (SEM) and powder X-ray diffraction (XRD) in order to estimate the extent of diagenetic alteration. The results suggest that the original microstructure and mineralogy of the shells are preserved. Antiserum raised against the Type-1 dermatopontin fragment of the living land snail Euhadra brandtii showed significant immunological reactivity with the extracts from the fossil shells of M. luhuana. Immunological binding curves drawn for the shell extracts of extant M. aureola and the extinct M. luhuana confirmed the presence of dermatopontin in the fossil shells and provided an estimate that about 75–98% of the original dermatopontin was lost from the M. luhuana fossils. This is the first report of a named protein being identified in invertebrate fossils.     

The influence of alongshore and cross‐shore wave energy flux on large‐ and small‐scale coastal erosion patterns

A strong low‐pressure system traveled along the Japanese main island Honshu in October 2006. High waves and storm surge attacked the Kashima Coast resulting in huge erosion over the area. Airborne laser data measured in October 2005 and November 2006 were analyzed to estimate cross‐sectional changes within the subaerial zone. The results of the alongshore distribution of the changes of cross‐sectional area indicate that the amount of erosion of the 38 km‐long northern and 15 km‐long southern parts decreased toward the south in each part and that the amount of erosion was smaller in protected areas with artificial headlands than in unprotected areas. The local alongshore variation of the erosion and accretion patterns showed wavy fluctuations of several hundreds of meters. The total amounts of the estimated eroded volume of the subaerial zone over the northern and southern parts were 620 000 m³ and 600 000 m³, respectively. The Simulating Waves Nearshore (SWAN) wave model was applied to estimate wave conditions along the coast during the storm. The computational results were verified, and then the alongshore distribution of wave energies, expressed as the alongshore and cross‐shore components of the wave energy flux, was compared with the alongshore distribution of cross‐sectional change. The results show that the distribution of energy flux explains the distribution of erosion well: The alongshore variability in the cross‐shore energy flux is responsible for the large‐scale variability in erosion, and shorter‐scale variability is due to gradients in the alongshore energy fluxes, especially for the areas without coastal works. Copyright © 2011 John Wiley & Sons, Ltd.     

Distribution of <Emphasis Type="Italic">Nemopilema nomurai</Emphasis> in the southwestern Sea of Japan related to meandering of the Tsushima Warm Current

We investigated the horizontal distribution of Nemopilema nomurai medusae using a midwater trawl in the southwestern Sea of Japan from September to October of each year from 2006 to 2012. Numerous medusae of this species found in 2006, 2007, and 2009 were mainly distributed far (>40 km) from the mainland of Japan in the western part of the survey area, but were distributed in the stations closest (<25 km) to the mainland in the eastern part, particularly in 2006 and 2009. These distribution patterns were associated with the path of the second branch of the Tsushima Warm Current (TWC) that flows offshore to the west of Oki Islands and usually approaches the mainland of Japan to the east of Oki Islands. Differences in jellyfish distribution across the survey periods were related to the distribution of the second branch being associated with types, position and intensity of eddies in the eastern part of the survey area. Hence, the formations of eddies and consequent variation in the path of the TWC would be responsible for transporting medusae from offshore to near the mainland to the east of Oki Islands. Individuals with large bells accumulated in the northwestern part of the survey area, where a cyclonic eddy was present downstream of the third branch of the TWC. This variation in bell size distribution may be ascribed to differences in the physical and/or biological factors among the three branches of the TWC.     

Trans-Equatorial Loop System Arising from Coronal Hole Boundaries through Interactions between Active Regions and Coronal Holes

It is not clear how trans-equatorial loop systems (TLSs) are formed, although they have been observed often with Yohkoh/SXT. We focus here on a TLS that appeared on 27 May 1998. Yokoyama and Masuda (Solar Phys. 254, 285, 2009) proposed a new scenario for the formation mechanism of the TLS. In this scenario, they pointed out the importance of magnetic interaction between an active region and a coronal hole to make “strong-seed magnetic fields” before a transient (bright and short-lived) trans-equatorial loop was created. The main aims of this study are to verify the scenario and to make the TLS formation mechanism clear, based on observational data. Yohkoh/SXT images, SOHO/MDI magnetograph data, and Kitt Peak coronal-hole maps were mainly used for our analyses. We investigated the TLS in detail from the time that there were no signatures of the TLS to its clear appearance. The following results are obtained: i) an active region emerged in the vicinity of a coronal-hole boundary, ii) the coronal-hole boundary retreated during the period when the active region was developing, iii) temporal variations of soft X-ray intensities were roughly synchronized between the coronal-hole boundary and a trans-equatorial region, and iv) new closed loops were observed in soft X-rays clearly at the coronal-hole boundary. Since i), ii), iii), and iv) are just what we expect in the scenario of YM2009, the scenario found support. We conclude that the TLS was originating with large-scale magnetic fields of the coronal-hole boundary through magnetic reconnection between the active region and a coronal hole.