重力场定义的澄清

《朗曼现代英文词典》(LongmanModernEnglishDictionary)、《牛津高阶英汉双解词典》(OxfordAdvancedLearner’sEnglish ChineseDictionary)、《韦氏词典》(Merriam Webster’sNewCollegiateDictionary)、作为地球物理专业词汇定义源的《勘探地球物理百科词典》(EncyclopedicDictionaryofExplorationGeo physics)以及中国的一些重力教科书、专著及词典 ,把重力场定义为重力或重力作用存在的空间 ,重力效应可以测量的空间 ,即 :力或重力存在的空间。这个定义不同于国外英文地球物理教科书、专著及中、英、俄文场论教科书对重力场的定义 :空间中的重力。定义重力场为重力存在的空间 ,混淆了“场”本身及“场域”的概念 ,并不是一个标准的物理或地球物理定义 ,是一种误导。物理场是空间中存在的一种物理作用或效应 ,分布于引起它的场源体周围。两个物体之间存在着的相互作用力 ,通过每个物体引起的引力场给予另一个物体。重力场可以定义如下 :地球内部及其附近空间一点处存在的重力作用 ,或单位质量受到的重力。重力场是一种力或力场 ,存在于地球表面及其附近的空间。重力场不是空间 ,重力场的测量应当是在重力场存在的空间或场域中 ,而不是在重力场中进行。     

Correlation of reefal Oxfordian episodes and climatic implications in the eastern Paris Basin (France)

Oxfordian reefal episodes of Lorraine and Burgundy have a long time been considered as contemporaneous. Biostratigraphic data and sequential evolutions peculiar to each region indicate their structural autonomy during Oxfordian times. A north‐south‐oriented well‐logging transect shows that, during the Middle Oxfordian, a shallow reefal platform developed in Lorraine while thin deeper deposits occurred in Burgundy. In spite of their different ages, reefal episodes of Middle Oxfordian in Lorraine and Upper Oxfordian in Burgundy exhibit a broadly similar vertical evolution of coral communities. During the Late Oxfordian, the contemporaneous occurrence of a diversified assemblage in the Burgundy region, a colder coral assemblage characterized by eurytopic genera and the decrease in seawater isotopic temperatures in Lorraine can be explained by a shift in trophic conditions, a climatic change related to structural rearrangements in this strategic place and a modification of oceanic circulations between the arctic and the Tethyan regions.     

Listric versus planar normal fault geometry: an example from the Eisenstadt-Sopron Basin (E Austria)

In a gravel pit at the eastern margin of the Eisenstadt-Sopron Basin, a satellite of Vienna Basin (Austria), Neogene sediments are exposed in the hanging wall of a major normal fault. The anticlinal structure and associated conjugated secondary normal faults were previously interpreted as a rollover anticline above a listric normal fault. The spatial orientation and distribution of sedimentary horizons and crosscutting faults were mapped in detail on a laser scan of the outcrop wall. Subsequently, in order to assess the 3D distribution and geometry of this fault system, a series of parallel ground penetrating radar (GPR) profiles were recorded behind the outcrop wall. Both outcrop and GPR data were compiled in a 3D structural model, providing the basis for a kinematic reconstruction of the fault plane using balanced cross-section techniques. However, the kinematic reconstruction results in a geologically meaningless normal fault cutting down- and up-section. Additionally, no evidence for a weak layer serving as ductile detachment horizon (i.e. salt or clay horizon) can be identified in stratigraphic profiles. Instead, the observed deflection of stratigraphic horizons may be caused by a displacement gradient along a planar master fault, with a maximum displacement in the fault centre, decreasing towards the fault tips. Accordingly, the observed deflection of markers in the hanging wall—and in a nearby location in the footwall of the normal fault—is interpreted as large-scale fault drag along a planar fault that records a displacement gradient, instead of a rollover anticline related to a listric fault.     

基于标准化降水指数的内蒙古地区干旱时空变化特征

利用内蒙古及周边地区70个气象站1951~2014年降水数据,采用标准化降水指数等方法,对内蒙古近64年气候干旱时空变化进行分析。结果表明:研究区近64年来除西部年际、春、秋、冬季,中部春、秋季及东部春、冬季气候趋于湿润外,其他均趋于干旱。中、东部年际、植(作)物生长期SPI在2001年和1990年左右发生突变,东部突变后趋于干旱并在2006年左右又发生明显转折后趋于湿润。西部在1960s干旱严重,中、东部在1990s至2000s干旱严重。西部年际SPI由西北向东南、东部由南向北干旱趋势速率呈阶梯状下降,中部干旱趋势速率较西、东部快;植(作)物生长期SPI空间变化与年际一致,但西、中部干旱趋势明显的区域有所扩大。     

1961-2010年西藏季节性冻土对气候变化的响应

利用西藏1961-2010年17个站点最大冻土深度、 土壤解冻日期等资料, 采用气候倾向率、 累积距平、 信噪比和R/S分析等方法, 分析了近50 a西藏季节性冻土的年际和年代际变化特征, 预估了未来50 a和100 a最大冻土深度变化. 结果表明: 近50 a林芝最大冻土深度以1.4 cm·(10a)^-1的速度增大, 其他站点均呈减小趋势, 为-0.7~-21.3 cm·(10a)^-1, 以那曲减幅最大. 近30 a来大部分站点最大冻土深度减幅更大, 为-0.92~-37.2 cm·(10a)^-1, 并随着海拔升高, 最大冻土深度减幅在加大. 近40 a来当雄、 江孜和林芝土壤解冻日期表现为推迟趋势, 为2.1~5.2 d·(10a)^-1, 其他站点呈提早趋势, 平均每10 a提早1.8~12.7 d. 在10 a际尺度变化上, 近40 a大部分站点年最大冻土深度呈逐年代变浅趋势, 土壤解冻日趋于提早. 那曲、 安多和泽当年最大冻土深度分别在1984、 1987年和1979年发生了突变, 从一个相对偏深期跃变为一个相对偏浅期. 近40 a来各站点年最大冻土深度的Hurst值均大于0.5, 说明未来大部分站点年最大冻土深度仍将变薄. 如果未来气候按升温率0.044 ℃·a^-1变化, 50 a后西藏最大冻土深度减小1.1~77.3 cm, 未来100 a可能减小1.2~91.4 cm; 气候按升温率0.052 ℃·a^-1变化, 50 a后最大冻土深度减小2.1~155 cm, 未来100 a可能减小2.5~183 cm. 最大冻土深度变浅显然与气温、 地温的显著升高直接有关.     

南京汤山温泉区地热水成因模式分析

汤山温泉是中国四大著名温泉疗养胜地之一,阐明其成因模式对于该温泉区的进一步开发和热水资源的可持续利用具有一定意义。基于硅-焓图解法和水文地球化学方法对其进行了系统研究,结果表明该区热储温度为90℃,岩溶热水与岩溶冷水、孔隙潜水和地表水之间在水化学和同位素组成上存在明显差异,地热井深度越大,冷水混入相对较少,地热水温度相对较高。经分析,该地热系统成因上属于中低温对流型。其补给区主要来自汤山山体(宁镇山区)及句容盆地东侧茅山山脉,循环深度为2.6~2.9 km,地热水通过汤山-东昌街断裂在浅部与区内NW向断裂、NE向断裂交汇形成温泉水。     

新疆乌拉泊水均衡试验场凝结水对地下水补给的观测研究

通过1989~1995年新疆乌拉泊水均衡试验场潜水埋深4m处包气带凝结水对地下水补给的观测:卵砾石2.58mm/a、细砾3.15mm/a、中砂9.90mm/a、细砂35..87mm/a、粉土10.04mm/a。最有利于包气带凝结水形成的时间是每年的4~9月;包气带凝结水量的大小与土体颗粒相对比表面积和渗透系数相关,推测粉砂的凝结水量约为20mm/a,粘性土小于10mm/a;凝结水对地下水补给的最大量约为50mm/a。综合气候和水文地质条件分析,认为本试验研究成果在我国西北干旱区具有代表性,估算西北地区凝结水对地下水的总补给量大于3×1010m3/a,可能大于平原降水入渗量,在某些区域可能是最主要的地下水补给源。     

A formation model for debris flows in the Chenyulan River Watershed, Taiwan

Many debris flows were triggered in the Chenyulan River Watershed in Taiwan in a rainstorm caused by the Typhoon Toraji. There are 117 gullies with a significant steep topography in the catchment. During this Typhoon, debris flows were initiated in 43 of these gullies, while in 34 gullies, it was not certain whether they have occurred. High-intensity short-duration rainfall was the main triggering factor for these gully type debris flows which are probably entrained by a “fire hose” mechanism. Previous research identified 47 factors related to topography, geology, and hydrology, which may play a role in the formation of gully type debris flows. For a better understanding of the probability of the formation of debris flows, it is proposed to represent the factors related to topography, geology, and hydrology by one single factor. In addition to the existing topographic and geological factor, a normalized critical rainfall factor is suggested with an effective cumulative precipitation and a maximum hourly rainfall intensity. In this paper, a formation model for debris flows is proposed, which combines these topographic, geological, and hydraulic factors. A relationship of these factors with a triggering threshold is proposed. The model produces a good assessment of the probability of occurrence of debris flows in the study area. The model may be used for the prediction of debris flows in other areas because it is mostly based on the initiation mechanisms and not only on the statistical analyses of a unique variety of local factors. The research provides a new and exciting way to study the occurrence of debris flows initiated by a “fire hose” mechanism.     

Two timescales in beach erosion due to decrease in sediment sources with special reference to the formation and reduction of the delta of the Kurobe River flowing into the Japan sea

Beach erosion has advanced in many countries of the world, especially in Japan, because of a decrease in sediment sources from rivers and a lack of longshore sediment transport from the adjacent coasts due to coastal structures. The former cause concerns the reduction of river deltas due to a decrease in sediment input from the river. Two timescales important in beach erosion, a longer timescale which concerns a change in the location of the river mouth, and a shorter one which is due to a decrease in longshore sediment transport, are discussed in the formation and reduction of the delta of the Kurobe River. Based on these timescales, beach erosion control is considered.     

Boundary element analysis of axially loaded piles embedded in a multi-layered soil

In a field, piles are likely installed in a multi-layered soil. Analysis of axially loaded piles in a multi-layered soil is complicated and deserves more attention. A boundary element method is used in this study to analyze an axially loaded single pile in a multi-layered soil using the solution for vertical and horizontal axisymmetric ring loads in a multi-layered elastic medium. Good and reasonable agreement is obtained between the proposed and published solutions for a single pile in a homogenous soil, a finite soil, and a Gibson soil. The proposed solution is also used to evaluate an axially loaded single pile in a multi-layered (8 layers) soil.     

A demonstration of an affinity between pyrite and organic matter in a hydrothermal setting

One of the key-principles of the iron-sulphur world theory is to bring organic molecules close enough to interact with each other, using the surface of pyrite as a substrate in a hydrothermal setting. The present paper explores the relationship of pyrite and organic matter in a hydrothermal setting from the geological record; in hydrothermal calcite veins from Carboniferous limestones in central Ireland. Here, the organic matter is accumulated as coatings around, and through, pyrite grains. Most of the pyrite grains are euhedral-subhedral crystals, ranging in size from ca 0.1-0.5 mm in diameter, and they are scattered throughout the matrix of the vein calcite. The organic matter was deposited from a hydrothermal fluid at a temperature of at least 200°C, and gives a Raman signature of disordered carbon. This study points to an example from a hydrothermal setting in the geological record, demonstrating that pyrite can have a high potential for the concentration and accumulation of organic materials.     

某水准路线所经地区现代升降运动的初步探讨

本文主要是利用水准复测资料来阐述某地区的现代升降运动。文中将复、初测高程进行比较,作出了现代地壳运动幅度图,图中看出东都上升幅度小,速度梯度变化也小;西部上升幅度大,速度梯度变化也大。在整个剖面中更可以看出,在较短距离内出现大幅度的隆起,隆起中又有相对凹陷。由实际资料得出,本区现代地壳运动有继承性,并出现三种类型的上升运动:(1)平稳的上升运动;(2)掀斜的上升运动;(3)强烈隆起。     

Parallel stretching lineations and fold axes oblique to a shear displacement direction—a model and observations

Spatial variations in shear strain rate are expected in ductile shear zones. Where the variation is a change in shear strain perpendicular to the displacement direction, the effect is to rotate the shear slip planes. This is a mechanism for giving a rotation of fold axes into parallelism with the slip and extension direction in a rock. If such a variation in shear strain affects rocks with a strong planar anisotropy it is possible to produce a fabric with an apparent stretching lineation parallel to fold axes, but both significantly oblique to the slip direction. A possible example of this is seen in strongly deformed quartz-mica schists from Syros, Greece, where a stretching lineation is seen parallel to fold hinges over a range of fold axes orientations of at least 40°.     

Review on Researches of Aragonite Saturation State in the Southern Ocean:A Key Parameter of Southern Ocean Acidification

The Southern Ocean is a strong sink for atmospheric CO₂, making it especially vulnerable to ocean acidification (OA). The aragonite saturation state (Ω_arg) of seawater has been used as an index for the estimation of OA, which plays a critical role in evaluating the living environment of marine calcified organisms. However, it is very difficult to perform the studies of OA and Ω_arg in the Southern Ocean due to its harsh climate. Therefore, in order to better understand the OA and its further influences, the advances of Ω_arg studies were summarized in the oceans surrounding the Antarctica. Significant spatial and temporal variations of surface seawater Ω_arg are demonstrated in the Southern Ocean. In general, the surface seawater Ω_arg shows a lower value in the off-shore areas than in the open oceans. And, Ω_arg also exhibits a strong seasonal cycle with a higher value in summer than in winter. The distributions of Ω_arg in vertical water column generally present a declining tendency from surface to bottom. In addition, the shoaling of Ω_arg horizon at high latitude could be attributed to the ventilation and upwelling of deep waters in the Southern Ocean. There are many factors that could impact the Ω_arg in the Southern Ocean, including sea ice melting, sea-air CO₂ exchange, biological activities and hydrological processes, etc. Finally, the future changes and key scientific problems of OA in the Southern Ocean are proposed.     

波的传播及其与介质间断相互作用的数值模拟研究

本文用有限差分法模拟研究二维空间中波的传播、散射及其与介质间断的相互作用。文章第一部分运用所模拟的纵波波源讨论了半无限空间表面台阶地形或槽形裂隙所造成的波的散射。这些间断可模拟具有波长量级的悬崖或狭谷。第二部分用差分法与扰动法结合而成的混合法处理半无限空间表面有另一种物质构成的表面浅障碍时波的传播,以模拟山脊、堑沟等地形的影响。此混合法也被用于讨论半无限空间内含有水平夹层或孔隙的问题。所得研究结果对波的传播及其与介质间断的相互作用的理论研究和地震波破坏效应的分析和隔离等应用研究有一定的意义。     

Geography in Australian education

Geography in Australia has a heritage that is strongly British, but more recently has been influenced from other parts of the world, such as North America and New Zealand. Its popularity has fluctuated and it is now under threat as a separate subject in the compulsory years of schooling. In higher education, geography has retrieved lost ground to be a popular area of study, but not a research area in the current national priorities. Geography plays a focal role in the general education of Australians. It is a medium for education involving the education of people, about, in, and for the society and environment in which they live. Through education, geography will enable people to explore their life-roles as learners, social beings, recreators, producers, consumers and citizens. It will develop in people distinctive knowledge, thinking processes, attitudes and values, and encourage participation in social and environmental actions. Teachers in secondary and higher education have differing and distinctive roles. Being a geographer in Australia does have benefits including: working in an identifiable area of knowledge maintaining a bridge across the physical and social sciences; the promotion of inquiry approaches and as a focus for the various adjectival educations that have emerged. These are tempered by challenges such as: threats from emerging disciplines, current national research priorities and the movement to social science education. Therefore, promotion of geography in Australia needs to be much more forceful than it has until now. The work of groups such as the Institute of Australian Geographers and the Australian Geography Teachers' Association needs to be co-ordinated more closely to develop a strong lobby for geography in Australian education.     

A robust debris-flow and GLOF risk management strategy for a data-scarce catchment in Santa Teresa,Peru

The town of Santa Teresa (Cusco Region, Peru) has been affected by several large debris-flow events in the recent past, which destroyed parts of the town and resulted in a resettlement of the municipality. Here, we present a risk analysis and a risk management strategy for debris-flows and glacier lake outbursts in the Sacsara catchment. Data scarcity and limited understanding of both physical and social processes impede a full quantitative risk assessment. Therefore, a bottom-up approach is chosen in order to establish an integrated risk management strategy that is robust against uncertainties in the risk analysis. With the Rapid Mass Movement Simulation (RAMMS) model, a reconstruction of a major event from 1998 in the Sacsara catchment is calculated, including a sensitivity analysis for various model parameters. Based on the simulation results, potential future debris-flows scenarios of different magnitudes, including outbursts of two glacier lakes, are modeled for assessing the hazard. For the local communities in the catchment, the hazard assessment is complemented by the analysis of high-resolution satellite imagery and fieldwork. Physical, social, economic, and institutional vulnerability are considered for the vulnerability assessment, and risk is eventually evaluated by crossing the local hazard maps with the vulnerability. Based on this risk analysis, a risk management strategy is developed, consisting of three complementing elements: (i) standardized risk sheets for the communities; (ii) activities with the local population and authorities to increase social and institutional preparedness; and (iii) a simple Early Warning System. By combining scientific, technical, and social aspects, this work is an example of a framework for an integrated risk management strategy in a data scarce, remote mountain catchment in a developing country.     

江苏镇江韦岗铁矿区深部找矿前景分析

镇江韦岗铁矿是一个已经勘查开发数十年的老矿山,目前保有资源储量保证程度已达严重危机。分析矿区成矿地质条件和矿床特征,铁矿体主要分布在碳酸盐岩层与中酸性侵入岩的接触带上,铁矿体普遍磁性强,且在地表形成一定规模的磁异常,梯度北陡南缓,向南有规则地递减呈梯形散开,说明矿体有一定的延伸。深部已施工的见矿钻孔和井中磁测异常对应,反映矿区深部-200m～-800m找矿前景良好。     

Geoheritage at the small scale: tidal-zone bubble-sand structures as diagnostic paleo-environmental indicators,and their geoheritage significance

In identifying sites of geoheritage significance, commonly there has been an emphasis on the larger-scale features. However, the story of geology and the significant features that are critical to unravel geological processes and geological history are commonly small in scale. This contribution focuses on bubble sand and bubble-sand structures as features that are small-scale but nonetheless important to geology, and hence are of geoheritage significance. Bubble sand and bubble-sand structures are ubiquitous on modern beaches and tidal flats, occurring in the uppermost tidal zone of sandy beaches, as a distinct layer in a shoaling beach-to-dune stratigraphy, and are a diagnostic indicator of upper-tidal conditions where a rising tide and a concomitantly rising water-table interacts with the upper swash-zone wave processes. On sandy tidal flats, bubble sand and bubble-sand structures may occur in the mid- to upper-tidal zones; here they are also diagnostic indicators of tidal conditions, forming during a rising tide where a rising water-table forces air upwards to be trapped in moist sand. If found in ancient sequences, bubble-sand structures are a powerful environmental indicator of tidal conditions and, for beach sequences, an indicator of the high-tide level and sea level. Bubble-sand structures have been found in a number of ancient sequences throughout the geological record as far back as the Neoproterozoic, e.g. within beach-to-dune stratigraphy in Pleistocene limestones of the Perth Basin and in southeastern USA, and in tidal-flat sands of the Mesozoic Broome Sandstone of the Canning Basin. The bubble-sand structure is a significant geological tool for use in paleo-environmental and paleo-oceanographic reconstructions, and determination of the position of a paleo-water-table. Given the rarity of their preservation, these occurrences of bubble-sand structures are of geoheritage significance in their own right and, depending on age of sequence and how common they are in the region, they may be nationally significant or globally significant.     

青海玉树断裂带地震落石的地震地质意义

2010年青海玉树Ms 7.1级大地震引发了一系列次生地质灾害,其中地震落石是除地震滑坡外沿断裂带及其邻侧最常见的现象。对玉树震区落石的调查发现,该区多处存在非常典型的多期地震落石分布现象,指示该区地震落石的发育与其他古地震现象类似,具有多期性和一定的原地复发性。实地调查表明,该区地震落石分布的主要特征为:多集中发育在活动断裂带附近的陡峭基岩斜坡下方,分布零散,且滚动较远,并常与古地震滑坡相伴生。初步获得的8个地震落石钙膜U系测年结果分布在距今6030±300a BP、4720±210a BP、3530±490~3560±280a BP、2010±160a BP、1090±70a BP、760±20a BP和230±20a BP年龄段,与该区古地震探槽和滑坡反映的地震事件比较吻合,进一步揭示玉树断裂带附近在全新世中晚期发生过多期可导致地表产生地震落石的事件。同时也说明,地震落石及其钙膜测年是特别值得进一步探索的潜在古地震研究方法或途径。