新疆康古尔断裂带东段的地球化学特征

新疆康古尔断裂带东段(土墩—黄山)的地球化学异常规模大,元素组合为铜、钴、镍铁、钒、钛、铬、钇、锆、铌、金、银等.从聚类分析、因子分析结果及镍、铬、钴、钛、钒累乘等值线图表明,康古尔断裂两侧地球化学系统明显不同,是性质不同的两个壳块.断裂带存在有“榴辉岩化地壳”.康古尔断裂可能是哈萨克斯坦—准噶尔古板块与塔里木古板块间的分界线.     

基于MBR的多边形内点自动生成算法

在分析传统多边形内点生成方法的基础上,提出一种基于MBR（MinimumBoundingRectangle,最小外切矩形）的内点自动生成算法,该方法不仅适用于凹、凸多边形,而且可保证在多边形具有“岛屿”时,内点正确。     

Facies characteristics and magma–water interaction of the White Trachytic Tuffs (Roccamonfina Volcano, southern Italy)

 The Quaternary White Trachytic Tuffs Formation from Roccamonfina Volcano (southern Italy) comprises four non-welded, trachytic, pyroclastic sequences bounded by paleosols, each of which corresponds to small- to intermediate-volume explosive eruptions from central vents. From oldest to youngest they are: White Trachytic Tuff (WTT) Cupa, WTT Aulpi, WTT S. Clemente, and WTT Galluccio. The WTT Galluccio eruption was the largest and emplaced ∼ 4 km³ of magma. The internal stratigraphy of all four WTT eruptive units is a complex association of fallout, surge, and pyroclastic flow deposits. Each eruptive unit is organized into two facies associations, Facies Association A below Facies Association B. The emplacement of the two facies associations may have been separated by short time breaks allowing for limited reworking and erosion. Facies Association A consists of interbedded fallout deposits, surge deposits, and subordinate ignimbrites. This facies association involved the eruption of the most evolved trachytic magma, and pumice clasts are white and well vesiculated. The grain size coarsens upward in Facies Association A, with upward increases of dune bedform wavelengths and a decrease in the proportion of fine ash. These trends could reflect an increase in eruption column height from the onset of the eruption and possibly also in mass eruption rate. Facies Association B comprises massive ignimbrites that are progressively richer in lithic clast content. This association involved the eruption of more mafic magma, and pumice clasts are gray and poorly vesiculated. Facies Association B is interpreted to record the climax of the eruption. Phreatomagmatic deposits occur at different stratigraphic levels in the four WTT and have different facies characteristics. The deposits reflect the style and degree of magma–water interaction and the local hydrogeology. Very fine-grained, lithic-poor phreatomagmatic surge deposits found at the base of WTT Cupa and WTT Galluccio could record the interaction of the erupting magma with a lake that occupied the Roccamonfina summit depression. Renewed magma–water interaction later in the WTT Galluccio eruption is indicated by fine grained, lithic-bearing phreatomagmatic fall and surge deposits occurring at the top of Facies Association A. They could be interpreted to reflect shifts of the magma fragmentation level to highly transmissive, regional aquifers located beneath the Roccamonfina edifice, possibly heralding a caldera collapse event. Received: 26 August 1996 / Accepted: 27 February 1998     

再论大震区的“长期活动”

从实际应用的需要出发,研究了中国大陆在发生Ｍｓ≥７．０地震２０年后震源区进入“长期活动”过程中后续地震强度演变的全部史料,发现在我国南北地震带以东的中国东部地区,发生Ｍｓ≥７．０大震后２－３年,最后１２年内,震区当地会发生Ｍｓ≥６．０地震。     

Spatial management of geotechnical data for site selection

A ground characterisation exercise was conducted in order to identify sites suitable for a blast furnace at the Redcar steelworks in northeast England. The purpose of this exercise, conducted some 20 years after the investigations were carried out and a decade after the steelworks had been constructed, was to develop techniques for managing spatial data using Geographical Information Systems (GIS) and geostatistics.

Borehole details, from the factual site investigation reports, were entered into a database using a relational structure with linked files. The borehole location and lithology files were keyed in using codes for geological material, weathering grade, strength, borehole type and verification status. Laboratory and field test data were input by scanning tables in the ground investigation reports and processing the scanned images using optical character recognition software.

The XBase programming language was used to execute graphing, GIS and geostatistics programs; thereby enabling repetitive tasks to be carried out by the computer. This both saved time and reduced errors and inconsistencies that could result from repeated manual execution of the same program. Some simple spatial operations could also be carried out entirely from within dBase, an example being the use of moving-window statistics employing rectangular windows aligned parallel to the axes of the coordinate system to study local stationarity.

GIS have been found to offer an effective tool for analysing, querying and presenting spatial site investigation information. Geostatistical kriging and simulation techniques offer powerful spatial modelling tools for creating visualisations of the spatial variability of parameters measured at points during a ground investigation.

The Redcar case history demonstrates how a database management system (DBMS) can be used to manipulate site investigation data as part of a modelling and interpretation exercise. DBase source code allows others to follow the same path or build upon the foundations herein.     

Zonation in primary halos and geochemical prospecting pattern for the Guilaizhuang gold deposit, eastern China

The Guilaizhuang gold deposit, with an average grade of 8.10 g/t Au and reserves of over 30 mt, is a subvolcanic epithermal deposit. The deposit is hosted in Paleozoic carbonate rocks in the western Shandong metallogenic terrane of the littorine Pacific metallogenic domain, eastern China, and is associated spatially with an early Mesozoic subvolcanic alkalic intrusive complex (188–190 Ma). The orebody was discovered at the end of the 1980s based on anomalies of Au in stream sediment samples at a map scale of 1∶200,000. The ore is rich in Au, Ag, Te, V, F, As, Sb, Tl, W, and Mo but poor in Cu, Pb, and Zn. The ore is similar in its trace elements to Carlin-type Au deposits. The transverse element association zonation of the deposit is as follows: (on the hanging wall) F⟸ W−Mo−As−Tl⟸Se−Sb−Bi⟸Au−Ag−Te (orebody) ⟹ Se−Sb−Bi (on the foot wall). The axial zonation is as follows: Au⟹Ag⟹Sb⟹V⟹Zn ⟹W⟹F⟹Mo⟹Tl⟹As. Indexes such as (Au+Sb) _d / (As+Tl) _d and (Au+ Ag) _d /(As+Tl) _d decrease with depth but dramatically increase at the level where the orebody pinches out, which indicates another orebody might exist at depth. Multivariate statistical analysis suggests that the ore (halo)-forming process can be divided into two stages: alteration and mineralization. The former includes: potash feldsparization, albitization, silicification, and fluoritization. The latter includes the following substages: arsenopyritization and scheelitization; pyritization, chalcopyritization, and sphaleritization; and native gold, electrum, and calaveritization. The last substage is considered to be the main ore-forming stage in the formation of the deposit.     

第四纪孢粉分析的时间序列与空间模型

论述了第四纪孢粉时间序列和孢粉空间模型在不同尺度上的时空代表性,同时介绍了一些相关的研究方法和主要成果。利用数理统计方法来定量恢复古气候已成为目前第四纪孢粉时间序列研究的一个发展趋势。各种尺度的第四纪孢粉空间模型图可以反映植被对第四纪气候变化的响应。根据孢粉数据与气候变量之间的函数关系还可换算成古气候图。此外,在全球气候模拟和植被模拟中,孢粉数据成为必不可少的诊断工具。     

论汽车工业空间组织之变化——生产方式转变的影响

汽车工业出现一百多年来空间组织发生了几次重要变化,而生产方式的转变是导致空间演化的主导因素之一。本文首先回顾了８０年代以前世界汽车工业空间组织的主要特征,并将其演化过程归纳为四个阶段,即初始分散阶段、大规模生产初期的高度集中阶段、“核心—边缘”结构阶段和网络化分散阶段。其次介绍了８０年代以来世界汽车工业发展的新特点,特别是精益生产方式的广泛扩散。最后归纳了新的生产方式下汽车工业空间组织的影响因素和特征,即网络化聚集,并简要地讨论了这种发展趋势对中国汽车工业的启示。     

Scaling smallholder tree cover restoration across the tropics

Restoring tree cover in tropical countries has the potential to benefit millions of smallholders through improvements in income and environmental services. However, despite their dominant landholding shares in many countries, smallholders’ role in restoration has not been addressed in prior global or pan-tropical restoration studies. We fill this lacuna by using global spatial data on trees and people, national indicators of enabling conditions, and micro-level expert information. We find that by 2050, low-cost restoration is feasible within 280, 200, and 60 million hectares of tropical croplands, pasturelands, and degraded forestlands, respectively. Such restoration could affect 210 million people in croplands, 59 million people in pasturelands and 22 million people in degraded forestlands. This predominance of low-cost restoration opportunity in populated agricultural lands has not been revealed by prior analyses of tree cover restoration potential. In countries with low-cost tropical restoration potential, smallholdings comprise a significant proportion of agricultural lands in Asia (∼76 %) and Africa (∼60 %) but not the Americas (∼3%). Thus, while the Americas account for approximately half of 21st century tropical deforestation, smallholder-based reforestation may play a larger role in efforts to reverse recent forest loss in Asia and Africa than in the Americas. Furthermore, our analyses show that countries with low-cost restoration potential largely lack policy commitments or smallholder supportive institutional and market conditions. Discussions among practitioners and researchers suggest that four principles – partnering with farmers and prioritizing their preferences, reducing uncertainty, strengthening markets, and mobilizing innovative financing – can help scale smallholder-driven restoration in the face of these challenges.     

An Investigation into the Ionic Chemical Composition and Mixing State of Biomass Burning Particles Recorded During TRACE-P P3B Flight#10

In this study bulk airborne aerosol composition measured by the PILS-IC (integration time of 3 min 24 s) during TRACE-P P3B Flight 10 are used to investigate the ionic chemical composition and mixing state of biomass burning particles. A biomass burning plume, roughly 3–4 days old, moderately influenced by urban pollution aerosols recorded in the Philippine Sea is investigated. Focusing on the fine particle NO₃⁻, SO₄²⁻, K⁺, NH₄⁺, and water-soluble organics, the observed correlations and nearly 1-to-1 molar ratios between K⁺ and NO₃⁻ and between NH₄⁺ and (SO₄²⁻+ inferred Organics) suggest the presence of fine-mode KNO₃, (NH₄)₂SO₄, and NH₄(Organics) aerosols. Under the assumption that these ion pairs existed, and because KNO₃ is thermodynamically less favored than K₂SO₄ in a mixture of NO₃⁻, SO₄²⁻, K⁺, NH₄⁺, and Organic anions, the measurements suggest that aerosols could be composed of biomass burning particles (KNO₃) mixed to a large degree externally with the (NH₄)₂SO₄ aerosols. A “closed-mode” thermodynamic aerosol simulation predicts that a degree of external mixing (by SO₄²⁻ mass) of 60 to 100% is necessary to achieve the observed ionic associations in terms of the existence of KNO₃. However, the degree of external mixing is most likely larger than 90%, based on both the presence of KNO₃ and the amounts of NH₄NO₃. Calculations are also shown that the aerosol mixing state significantly impacts particle growth by water condensation/evaporation. In the case of P3B Flight #10, the internal mixture is generally more hygroscopic than the external mixture. This method for estimating particle mixing state from bulk aerosol data is less definitive than single particle analysis, but because the data are quantitative, it may provide a complementary method to single particle chemical analysis.