1993年10－12月的全球地震动态     

吴佳翼 《国际地震动态》1994,(5)

１９９３年第四季度，全球地震活动为中等水平，三个月内共发生三次７．１级浅源地震。新几内亚东部发生６－７级地震多次。美州地震带地震活动表现不强。堪察加以东近海发生７．１级地震。亚欧带于１０月２日发生中国新疆南部（若羌）地震。全球浅源地震相对活跃。  相似文献   

Organic biomarkers for tracing carbon cycling in the Gulf of Papua (Papua New Guinea)   总被引：1，自引：0，他引：1  

K.A. Burns  P. Greenwood  R. Benner  D. Brinkman  G. Brunskill  S. Codi  I. Zagorskis 《Continental Shelf Research》2004,24(19):2373-2394

Sediment traps were deployed in the Gulf of Papua in June–July 1997, to determine fluxes of organic matter and inorganic elements from the photic zone to deeper waters at the base of the continental slope and in the northern Coral Sea. Three stations, ranging from 900 to 1500 m depth, had “shallow” traps at 300 m below the water surface and “deep” traps set 100 m above the bottom. Infiltrex II water samplers collected particulate and dissolved organic matter from the Fly, Purari and Kikori rivers, and near-surface water from the shelf of the Gulf of Papua. Samples were analysed for molecular organic biomarkers to estimate the sources of organic carbon and its cycling processes.Dry weight fluxes from the shallow traps ranged from 115 to 181 mg m⁻² day⁻¹ and particulate organic carbon (POC) fluxes ranged from 1.2 to 1.9 mM OC m⁻² d⁻¹ with molar organic carbon to particulate nitrogen ratios (C/N) ranging from 6.0 to 6.5. Fluxes in deep traps were likely influenced by both early diagenesis and entrapment of resuspended shelf sediments. Dry weight fluxes in deep traps ranged from 106 to 574 mg m⁻² day⁻¹ and POC fluxes ranged from 0.6 to 1.5 mM OC m⁻² d⁻¹, with C/N ratios ranging from 8.5 to 10.8. ¹³C/¹²C ratios were −20.2‰ to −21.7‰ in all trap samples, indicating that most of the settling POC was “marine-derived”. Shallow traps had δ¹⁵N values of 6.3‰ to 7.2‰ while the values in deep traps were 4.9–5.0‰, indicating the N-rich near-surface OC was less degraded than that in the deep traps. The biogenic lipids consisted of hydrocarbon, sterol and fatty acid biomarkers indicative of marine zooplankton, phytoplankton and bacteria. Sterol markers for diatoms and dinoflagellates were abundant in the water samples. Highly branched isoprenoid alkenes, usually attributable to diatoms, were also detected in both water and shallow traps. Traces of C₂₆–C₃₄ n-alcohols indicative of land–plant biomarkers, were found in river water samples and in the shallow sediment traps. A large unresolved complex mixture (UCM) of hydrocarbons, and a uniform distribution of n-alkanes, indicative of petroleum hydrocarbons, were also detected in the traps. Hopane and sterane biomarkers detected in the trap oil were characteristic of a marine carbonate source, and the aromatic hydrocarbon composition distinguished at least two different oil signatures.We concluded that mass and POC fluxes were similar to those reported for other continental shelves and marginal oceans in tropical and subtropical regions. There was a dramatic decrease in POC as particles sank, due to zooplankton repackaging and photochemical and bacterial decomposition. Carbon isotopic and biomarker patterns showed most of the POC in the sediment traps was marine-sourced with only traces of terrestrial input. There was a significant flux of petroleum, which may signal the existence of natural petroleum seeps in this region.  相似文献   

Clinoform mechanics in the Gulf of Papua, New Guinea   总被引：1，自引：0，他引：1  

J.P. Walsh  C.A. Nittrouer  C.M. Palinkas  A.S. Ogston  R.W. Sternberg  G.J. Brunskill 《Continental Shelf Research》2004,24(19):2487-2510

The largest islands of the Indo-Pacific Archipelago are estimated to account for 20–25% of the global sediment discharge to the ocean, and much (>50%) of this sediment is supplied to wide (>150 km) continental shelves. These conditions are conducive to creation of large-scale morphologic features known as clinoforms—sigmoidal-shaped deposits on the continental shelf. The Gulf of Papua (GOP) receives 3.84 ×10⁸ tons of sediment annually from three principal sediment suppliers, the Fly, Kikori and Purari Rivers, and its prograding clinoform is the focus of this study. During three research cruises, 80 cores and 37 CTD/optical backscatter casts were collected, and an instrumented tripod was deployed twice. Sedimentological and radiochemical results indicate that the GOP clinoform has characteristics similar to those seaward of other major rivers (e.g., Amazon, Ganges–Brahmaputra), specifically sand/mud interbedding on the topset, rapidly accumulating muds on the foreset, and siliciclastic mud mixed with carbonate sand on the bottomset.Using core data and field observations, the mechanics of clinoform progradation are examined. Discrete, large sedimentation events are identified as processes building the clinoform feature. X-radiographs from foreset cores reveal thick beds (>5 cm) between bioturbated sections. Detailed ²¹⁰Pb and grain-size data indicate that low activities and increased clay contents are associated with these beds. They are hypothesized to be formed by fluid–mud deposition in response to periods of large wave-tide bed shear stresses, more likely during the SE-tradewind season, and their regular occurrence produces high rates of mean accumulation (4 cm/y). Bed preservation is determined by the rates of sediment accumulation and bioturbation.To assess the influence of physical oceanographic factors on clinoform shape, bottom shear stresses from tides and surface waves were calculated using available wave and tripod data. This effort reveals that the depth range (25–40 m) of the clinoform rollover point (seaward edge of the topset region) is roughly consistent with the sediment-transport regime. Furthermore, calculations corroborate the core data that suggest possible seasonal sediment storage in the inner topset region (<15-m water depth, during the NW-monsoon winds) with subsequent transfer to foreset beds (more probable during SE-tradewind conditions).A 100-yr sediment budget created with accumulation rate data suggests approximately 20% of the total sediment supplied to the GOP accumulates on the clinoform (creating the clinoform morphology). Less than 5% is believed to escape to the adjacent slope, and much of the remaining 75% is likely trapped on the inner-topset region (<20 m water depth) and within the mangrove forests and flood/delta plains of the northern GOP.  相似文献   

A seismological study of the eastern New Guinea and the western Solomon Sea regions and its tectonic implications   总被引：1，自引：0，他引：1  

G. Pegler  S. Das  J. H. Woodhouse 《Geophysical Journal International》1995,122(3):961-981

  相似文献   

The discourses of climate change science: Scientific reporting,climate negotiations and the case of Papua New Guinea     

《Global Environmental Change》2019

This paper analyses climate science as a discourse to reveal how it enables and constrains climate change negotiations and action. Focusing on long-term outcomes projected in the Intergovernmental Panel on Climate Change’s Fifth Assessment Report and the World Bank’s “Turn Down the Heat” reports, this paper examines processes of discourse structuration and institutionalization to identify the dominant discourses which frame climate action. We trace the dominant discourses identified in the scientific reports – Survivalism, Ecological Modernisation and Economic Rationalism – through the Paris Agreement and selected Leader Statements and Intended Nationally Determined Contributions from COP21. From the 24 states included in this analysis, Papua New Guinea (PNG) is developed as a case study to investigate the hybridity and institutionalization of discourses. Even though PNG’s rhetoric and commitments at COP21 express Survivalism, the state’s policy frameworks rarely move beyond solutions found in Economic Rationalism and Ecological Modernisation. This suggests that states strategically adopt hybrid discourses drawn from climate science in line with their positionality, political economy and interests. Understanding how discourses drawn from climate science manifest in national policies has significant implications not only for how science is communicated at the international level but also for understanding different state positions in the global climate governance regime.  相似文献   

几内亚矿产开发现状及矿业投资展望     

宋崇宇 《地质与勘探》2021,57(6):1287-1296

几内亚矿产资源丰富,铝土矿储量居世界首位,拥有宁巴山和西芒杜两座世界级铁矿床,石墨、金、金刚石等矿产资源也较丰富。矿业在其国民经济中占有十分重要的地位,丰富的资源吸引了力拓、俄罗斯铝业等国际大型矿业公司和赢联盟、中国铝业集团、中国河南国际等中资矿企在几内亚从事矿业开发。中几两国友好交往源远流长,经济互利合作不断发展。中国是几内亚第一大铝土矿出口国,同时也是几内亚第二大进口来源国,据商务部统计,2019年我与几内亚双边贸易额同比增长17.6%。本文系统梳理了几内亚的地质概况、主要矿产资源、勘查开发现状,认为几内亚丰富的矿产资源与我国具有良好的资源互补性。双方矿业合作互利共赢,随着政府及企业在基础设施建设的投资不断增加,几内亚矿业投资前景良好,有望成为中国海外矿业新基地。  相似文献   

Tidal sediment transport versus freshwater flood events in the Konkouré Estuary, Republic of Guinea     

Sylvain Capo  Isabelle Brenon  Aldo Sottolichio  Patrice Castaing  Patrick Le Goulven 《Journal of African Earth Sciences》2009,55(1-2):52

In comparison to their temperate counterparts, sediment processes in tropical estuaries are poorly known and especially in African ones. The hydrodynamics of such environments is controlled by a combination of multiple processes including morphology, salinity, mangrove vegetation, tidal processes, river discharge, settling and erosion of mud and by physico-chemical processes as well as sediment dynamics.The aim of this study is to understand the sediment processes in this transitional stage of the estuary when the balance between river discharges and marine processes is reversing. Studying the hydrodynamics and sediment dynamics of the Konkouré Estuary has recently been made possible thanks to new data on bathymetry, sedimentary cover, salinity, water elevations, and current velocities. The Lower Konkouré is a shallow, funnel shaped, mesotidal mangrove-fringed, tide-dominated estuary, well mixed during low river discharge and stratified during high river discharge. The Konkouré Estuary is turbid despite the small amount of terrestrial input and its residual velocity at the mouth during low river discharges, landwards for two of the three branches, suggests a landward migration by tidal pumping of the suspended particulate matter. A Turbidity Maximum Zone (TMZ) is identified for typical states of the estuary with regard to fluvial and tidal components. Suspended sediment transport during a transitional stage between the rainy and dry seasons is known thanks to current velocity and Suspended Sediment Concentration (SSC) measurements taken in November 2003. The Richardson layered number calculation assesses that turbulence is the major mixing process in the water column, at least during the flood and ebb stages, whereas stratification occurs during the slack water periods. Tidal currents generate bottom erosion, and turbulence mixes the suspended sediment throughout the water column. As a result, a net sediment input is calculated from the western Konkouré outlet for two consecutive tidal cycles. Despite the net water export, almost 300 tons per tide reach the estuary through this outlet, for a moderate river flow.  相似文献   

几内亚红土型铝土矿床地质特征   总被引：1，自引：0，他引：1  

高灶其  樊克锋 《火山地质与矿产》2009,(2):115-118

几内亚铝土矿资源丰富,并具有品位高,富铝、高铁、低硅、易采、易选之特点,属富含三水铝石的红土型铝土矿。硅铝铁风化壳是本区的含矿岩系,主要矿石类型为蜂窝状、土状和块状铝土矿。矿体多赋存于山体顶部和坡度适中的斜坡上,地形平坦地段和沟谷部位矿体质量差或无矿体。几内亚属于湿热多雨和干湿交替的热带气候,为红土型铝土矿的形成提供了有利条件。广泛分布的富铝基性岩石是铝土矿的母岩,也是形成铝土矿的基本前提。  相似文献   

Finding common ground: relational concepts of land tenure and economy in the oil palm frontier of Papua New Guinea   总被引：1，自引：0，他引：1  

GEORGE N CURRY  GINA KOCZBERSKI 《The Geographical journal》2009,175(2):98-111

In the oil palm frontier regions of West New Britain and Oro provinces, Papua New Guinea, customary land tenure arrangements are changing in response to the growing demand for land for agricultural development. This paper examines one aspect of these changes, namely the gifting and selling of customary land for oil palm development to people who have no customary birthrights to the land. By analysing how access rights are maintained over the relatively long cultivation cycle of oil palm (approximately 25 years), and in the context of the rapidly changing socio-economic and demographic environments of the oil palm frontiers, the paper demonstrates that while land transactions seemingly entail the commodification of land, land rights and security of land tenure remain embedded in social relationships. For customary landowners, the moral basis of land rights is contingent on 'outsiders' maintaining particular kinds of social and economic relationships with their customary landowning 'hosts'. In exploring how these social relationships are constituted through the performance of particular kinds of exchange relationships, the paper provides insights into relational concepts of land rights and how these are able to persist in Papua New Guinea's oil palm frontier regions where resource struggles are often intense and where large migrant populations are seeking land for agricultural development.  相似文献   

Copper‐gold mineralisation in New Guinea: Tectonics,lineaments, thermochronology and structure     

K. C. Hill  R. D. Kendrick  P. V. Crowhurst  P. A. Gow 《Australian Journal of Earth Sciences》2013,60(4):737-752

In New Guinea, the upper crust is rich in Late Miocene and Pliocene copper‐gold deposits, yet the host intrusives are mainly in the New Guinea Fold Belt and are of mantle origin and not directly subduction‐related. Structural, thermochronological and geodynamic analyses of the Grasberg, Porgera, Ok Tedi and Frieda River deposits show that the richest deposits occur along the eastern edge of the intersections between long‐lived crustal transfers perpendicular to strike and strike‐parallel crustal extensional faults that were strongly inverted during Late Miocene ‐ Pliocene orogenesis. The deposits are all associated with north‐northeast‐trending transfers, parallel to the aeromagnetic grain in basement, across which the continent‐ocean suture shows >50 km horizontal separation, as identified by the southern limit of the central New Guinea ophiolites. In the fold belt, the transfers coincide with the termination of regional anticlines or uplifts that are 150–200 km long and 30–60 km wide. Balanced sections reveal that the southern limit of these regional anticlines is commonly fault‐bound and coincides with major facies and thickness changes, indicating long‐lived, crustal extensional faults that were inverted. Fission track and ⁴⁰Ar/³⁹Ar cooling ages show that mineralisation occurred during inversion of these faults and, hence, correlates with propagation of orogenesis from northeast to southwest. It is proposed that the pre‐compression New Guinea margin comprised step‐like promontories and embayments delineated by long‐lived crustal fracture zones, as on Australia's North West Shelf. During Late Miocene ‐ Pliocene compression the crust was thickened, accompanying melting of the underlying mantle, and the crustal fracture zones were reactivated as transfers. Where the transfers intersected crustal extensional faults that were being inverted, local zones of dilation occurred, allowing emplacement of mantle magmas and associated mineralisation. When the deformation propagated southwards, so did the crustal thickening and the reactivation of major faults, allowing emplacement of younger magmas and mineralisation.  相似文献