唐山几次强余震前地震活动标度的异常特征分析

本文计算了1980年1月——1987年4月唐山老震区余震序列的地震活动标度值。通过数据处理,分折讨论了在此期间所发生的4次强余震前,地震活动标度的异常特征。     

Economic value of marine ecosystem services in Zanzibar: Implications for marine conservation and sustainable development

Marine ecosystem services are seriously undervalued, resulting in under-investment in conservation and lost opportunities for economic growth and poverty reduction. Economic valuation provides a powerful tool for sustainable development by showing how dependent the economy is on an ecosystem and what would be lost if the ecosystem is not protected. This paper estimates the value of marine ecosystem services in Zanzibar, links the values to the national income accounts, and quantifies how the benefits from each ecosystem service are distributed among five different stakeholder groups. Marine ecosystem services contribute 30% of GDP, yet the ecosystem is seriously degraded due to both human and natural causes. The paper explores the reasons for this, focusing on the distribution of benefits and the (dis)incentives this creates for conservation, especially among local communities that steward the marine ecosystem.     

Sulphate-related equilibria in the hypersaline brines of the Tyro and Bannock Basins, eastern Mediterranean

The Tyro and Bannock Basins, which are depressions in the eastern Mediterranean, contain hypersaline anoxic brines. These brines are of different composition: Tyro brine is primarily an early-stage halite (NaCl) brine, whereas Bannock brine includes the more soluble ions of late-stage evaporite minerals. Accordingly, the Bannock brine contains a much greater sulphate concentration than the Tyro Brine. This difference in sulphate concentration is reflected in the concentrations of ions such as Ca, Sr and Ba, which form sparingly soluble sulphate minerals.Equilibrium calculations using the Pitzer specific ion interaction model indicate that the brines in both basins are saturated with respect to gypsum (CaSO₄-2H₂O) and supersaturated to saturated with respect to dolomite (CaMg(CO₃)₂). The degree of saturation with respect to dolomite is greater in the Bannock Basin than it is in the Tyro Basin. Correspondingly, recent gypsum crystals and dolomite hardgrounds have been found in the Bannock Basin but not in the Tyro Basin.The Tyro brine is homogeneous in composition, whereas the Bannock brine demonstrates a clear two-layer brine structure. At the interface of the upper and the lower brine distinct positive anomalies occur in the total alkalinity and the concentration of phosphate, and negative anomalies occur in the concentrations of Mn²⁺ and the rare earth elements (REE). These anomalies and the observed association of gypsum/dolomite in the sediments are all consistent with a recent precipitation of dolomite and gypsum in the Bannock Basin. The brines in both basins are also saturated with respect to barite (BaSO₄).The ⁸⁷Sr/⁸⁶Sr and δ³⁴S ratios of the Bannock brines are amazingly consistent but differ dramatically from the values for modern or Messinian-age seawater. The Sr concentration and Sr and S isotope ratios in the gypsum crystals indicate that most of these crystals have resulted from precipitation/recrystallization from the brine and not from seawater. The observed variations between crystals are thought to reflect the recrystallization of (sub-) outcropping Messinian gypsum with a low ⁸⁷Sr/⁸⁶Sr ratio in the presence of seawater or brine fluids and with different extents of diagenesis.     

Surface NMR within a geophysical study of an aquifer at Haldensleben (Germany)

The surface nuclear magnetic resonance (SNMR) method has been tested at a site in Haldensleben, northern Germany, to assess the suitability of this new method for groundwater exploration and environmental investigations. More information is obtained by SNMR, particularly with respect to aquifer parameters, than with other geophysical techniques. SNMR measurements were carried out at three borehole locations, together with 2D and 1D direct current geoelectrics, as well as ground-penetrating radar, and well logging (induction log, gamma-ray log and pulsed neutron-gamma log). Permeabilities were calculated from the grain-size distributions of core material determined in the laboratory. It is demonstrated that the SNMR method is able to detect groundwater and the results are in good agreement with other geophysical and hydrogeological data. Using the SNMR method, the water content of the unsaturated and saturated zones (i.e. porosity of an aquifer) can be reliably determined. This information and resistivity data permit in situ determination of other aquifer parameters. Comparison of the SNMR results with borehole data clearly shows that the water content determined by SNMR is the free or mobile water in the pores. The permeabilities estimated from the SNMR decay times are similar to those derived from sieve analysis of core material. Thus, the combination of SNMR with geoelectric methods promises to be a powerful tool for studying aquifer properties.     

Burial and degradation of Rena oil within coastal sediments of the Bay of Plenty

ABSTRACT

During the Rena oil spill, no data existed for New Zealand conditions on the likely depth of burial and the expected degradation of oil deposited on sandy beaches. Sediment cores were taken from 12 locations along the Bay of Plenty coastline c. 1 year after the Rena oil spill. No visible oil was detected in cores and trenches dug within the beaches. Chemical extraction was performed on 20?cm slices from the upper 40?cm of 26 cores, and the elutriates were analysed for the presence of polycyclic aromatic hydrocarbons (PAHs). The results were compared with known PAH fingerprints of Rena oil and its degradation products. Only seven samples contained some marker PAHs, and none had a complete Rena profile, indicating stormwater contamination. Despite extensive deposition of Rena oil on beaches, no evidence of ongoing contamination could be located, indicating that the clean-up and degradation were effective at removing the oil.     

Single-zircon Pb-evaporation and 40Ar/39Ar dating of the metamorphic and granitic rocks in north-west Spitsbergen

North-west Spitsbergen consists of a complex of Caledonian and Grenvillian crystalline rocks, situated at the north-west corner of the Barents Shelf. The aim of this study is to understand the extent of pre-Caledonian basement rocks and their protoliths. Micas and zircon grains from six rocks from north-west Spitsbergen have been dated by the ⁴⁰Ar/³⁹Ar and single-zircon Pb-evaporation methods. Two grey granites yielded Late Caledonian mica ⁴⁰Ar/³⁹Ar and zircon ages of ca. 420-430 My, with inherited zircon grains as old as 1725 My. Zircon grains from a gneissose granite xenolith in a grey granites gave crystallization ages of ca. 960 My; some grains from a migmatite neosome show similar ages. Zircon grains yielding Archean and late Palaeoproterozoic ages (1600-1800 My) are interpreted as xenocrysts of detrital origin. The youngest ages obtained from detrital zircon grains from a greenschist facies quartzite of the Signehamna unit are ca. 1800 My. Similar schists are included as xenoliths in the 960 My old gneissose granite; therefore, the sedimentary protoliths of the unit are Mesoproterozoic. The dating results suggest a significant tectonothermal event during Grenvillian time; subsequent Caledonian events had less extensive thermal effects. However, it is still a matter of debate whether Grenvillian or Caledonian metamorphism produced the majority of the migmatites. A large population of zircon grains with Late Palaeoproterozoic ages suggests a wide surface exposure of rocks of this age in the source area, with some Archean zircons.     

Late permian changes in conditions of the atmosphere and environments caused by halogenated gases

Doklady Earth Sciences -     

Matching INSPIRE Quality of Service Requirements with Hybrid Clouds

A lot of effort has been invested in Spatial Data Infrastructures (SDIs) during the last decade regarding interoperable standards for services and data. But still the scalability and performance of SDI services is reported to be crucial especially if they are accessed concurrently by a high number of users. Furthermore, laws and provisions such as the INSPIRE directive specify challenging requirements regarding the performance, availability and scalability of SDI services. This article presents a Hybrid Cloud architecture for matching INSPIRE‐related Quality of Service (QoS) requirements, without investing in rarely used hardware in advance, by occupying external third‐party resources on a pay‐as‐you‐go basis. The presented Hybrid Cloud is a composition of a local IT‐infrastructure (Private Cloud) and the computational resources of third‐party vendors (Public Cloud). The local infrastructure is laid out to handle the average main load of a service and in lasting peak times additional resources of external providers are allocated and integrated on demand into the local infrastructure to provide sufficient service quality automatically. A proof‐of‐concept implementation of the proposed Hybrid Cloud approach is evaluated and benchmarked with respect to INSPIRE‐related QoS requirements.     

THE GALATIA,KANSAS, CHONDRITE

The Galatia meteorite was found in August, 1971, approximately 7 km ENE of Galatia, Barton County, Kansas (98° 53′W., 38° 39.5′N). The single stone weighed 23.9 kg and is partially weathered. Olivine (Fa_24.9) and pyroxene (Fs_20.9) compositions indicate L-group classification, and textural observations indicate that the stone is of petrologic type 6. Galatia is similar in many respects to the Otis L6 chondrite (found 20 km to the west), but it does not have the brecciated structure of Otis and, thus, it is not part of the same fall.     

The structure of phytoplankton communities in the eastern part of the Laptev Sea

Studies have been performed on a transect along 130°30′ E from the Lena River delta (71°60′ N) to the continental slope and adjacent deepwater area (78°22′ N) of the Laptev Sea in September 2015. The structure of phytoplankton communities has distinct latitudinal zoning. The southern part of the shelf (southward of 73°10′ N), the most desalinated by riverine discharge, houses a phytoplankton community with a biomass of 175–840 mg/m², domination of freshwater Aulacoseira diatoms, and significant contribution of green algae (both in abundance and biomass). The northern border for the distribution range of the southern complex of phytoplankton species lies between the 8 and 18 psu isohalines (~73°10′ N). The continental slope and deepwater areas of the Laptev Sea (north of 77°30′ N), with a salinity of >27 psu in the upper mixed layer, are populated by the community prevalently composed of Chaetoceros and Rhizosolenia diatoms, very abundant in the Arctic, and dinoflagellates. The phytoplankton number in this area fall in the range of 430–1100 × 10⁶ cell/m², and the biomass, in the range of 3600 mg/m². A moderate desalinating impact of the Lena River discharge is observed in the outer shelf area between 73°20′ and 77°30′ N; the salinity in the upper mixed layer is 18–24 psu. The phytocenosis in this area has a mosaic spatial structure with between-station variation in the shares of different alga groups in the community, cell number of 117–1200 × 10⁶ cells/m², and a biomass of 1600–3600 mg/m². As is shown, local inflow of “fresh” nutrients to the euphotic layer in the fall season leads to mass growth of diatoms.