江西省九江市规划区地下水特征及其环境评价

在分析介绍九江地区地下水类型(松散岩类孔隙水、碳酸盐岩裂隙岩溶水、基岩裂隙水)和地下水环境条件及其动态变化规律的基础上,采用《生活饮用水卫生标准》,对研究区地下水环境,包括地下水质量和地下水污染现状进行了评价。研究区内合格的地下水占56%,不合格的占12%,中等不合格占16%,严重不合格占16%。地下水污染形成了4个严重污染区块,全区未污染地下水仅占8%、轻微污染占36%、中等污染占20%、严重污染占36%。污染项目主要为PH、氨氮、硝酸盐、亚硝酸盐、氛等指标。由此提出了保护地下水资源的建议。     

Evolution of the passive continental margins of India—a geophysical appraisal

The passive continental margins of India have evolved as India broke and drifted away from East Antarctica, Madagascar and Seychelles at various geological times. In this study, we have attempted to collate and re-examine gravity and topographic/bathymetry data over India and the adjoining oceans to understand the structure and tectonic evolution of these margins, including processes such as crustal/lithosphere extension, subsidence due to sedimentation, magmatic underplating and so on. The Eastern Continental Margin of India (ECMI) seems to have evolved in a complex rift and shear tectonic settings in its northern and southern segments, respectively, and bears similarities with its conjugate in East Antarctica. Crustal extension rates are uniform along the stretch of the ECMI in spite of the presence or absence of crustal underplated material, variability in lithospheric strength and tectonic style of evolution ranging from rifting to shearing. The Krishna-Godavari basin is underlain by a strong ( 30 km) elastic lithosphere, while the Cauvery basin is underlain by a thin elastic lithosphere ( 3 km). The coupling between the ocean and continent lithosphere along the rifted segment of the ECMI is across a stretched continental crust, while it is direct beneath the Cauvery basin. The Western Continental Margin of India (WCMI) seems to have developed in an oblique rift setting with a strike-slip component. Unlike the ECMI, the WCMI is in striking contrast with its conjugate in the eastern margin of Madagascar in respect of sedimentation processes and alignment of magnetic lineations and fracture zones. The break up between eastern India and East Antarctica seems to have been accommodated along a Proterozoic mobile belt, while that between western India and Madagascar is along a combination of both mobile belt and cratonic blocks.     

The Indian monsoon and its economic impact

Indian economy is vitally linked with the monsoon because of its water resources. A large part of the country gets more than 75% of the annual rainfall during the four months, June to September.The production of foodgrains depends fairly closely on the amount and distribution of monsoon rainfall over the country. Further the generation of hydro-electric power from monsoon rain water has been traced over the last 20 years. While hydro-electric power constitutes about 40% of power from all sources, with proper surveys and planning additional hydro-electric power projects this percentage could, perhaps, be further substantially increased. The distinct advantage of hydro-electric power over all other types of power is that its source, i.e. monsoon water, is perennial, although it shows some fluctuations from year to year. The power of the monsoon winds at four and two stations on the West coast and in the interior resp. has been assessed on the basis of five years hourly wind data. The wind at New Kandla on the West coast has a good potentiality for power. The wind power could be used for electricity, grinding corn and drawing water. On the debit side, Indian economy suffers heavy losses due to floods and droughts almost every year.The population of India is increasing at a much faster rate than the total foodgrains production and soon the country may be facing a serious economic crisis. A large part of the monsoon water which is currently unutilized should be held at suitable locations for irrigation and possible power generation.     

西安地铁施工诱发地表沉降及对城墙的影响

以西安地铁2号线为背景,利用3种预测公式对实测地表沉降值进行拟合,得到了沉降槽形态参数。利用拟合参数,借鉴“刚度修正法”原理对地铁下穿城墙施工诱发其基础的沉降进行预测,并建立城墙的三维有限元模型,对城墙所能承受的极限变形能力和承载力进行量化分析,分析结果表明：Peck公式能较好地描述地表沉降特征;考虑后期蠕变和固结作用,盾构施工所诱发的城墙基础最大沉降量不得超过20 mm,期望对后期地铁施工引起地表沉降及其对建筑物的响应提供科学参考。     

The illite 'crystallinity'technique: a critical appraisal of its precision

Analysis of the precision of the illite 'crystallinity'technique shows that machine errors are <5%, while intra- and inter-sample errors are variable but are up to 12% and 14%, respectively (1σ). Consideration of this error analysis shows that the isocryst approach, which involves close contouring (e.g. 0.03 Δ2°) of illite 'crystallinity'data, has a very low degree of confidence (<0.5) and thus is not regarded as statistically valid. If contouring is to be undertaken with a high degree of confidence (>0.8) it is necessary that contours should be at intervals of 0.1 ΔΘ2°, which is equivalent to subdivision of the anchizone into upper and lower units. Where previous interpretations have relied upon an isocryst method of contouring at less than 0.1 ΔΘ2° the conclusions must be regarded as unsubstantiated.
Centrifuge separation of clay fractions (based on a Stokes'law application) gives separations in which a significant, but variable, percentage of grains have long axes greater than the size calculated. For the typical <2-μm fraction utilized, some 20% of grains lie in the 2–4-μm range, although the proportion is not believed to have a significant effect upon 'crystallinity'values. The formula is applicable for grain-sizes down to 0.5 μm. Illite 'crystallinity'values on samples prepared by an ultrasonic disaggregation method show a small increase on those prepared by ball mill crushing. The differences are minimal at the epi/anchizone level but increase to some 10% at the anchizone/diagenetic level. The effect on grade determinations is again thought to be minimal and indicates that concern over unsuitability of the ultrasonic disaggregation method is unfounded.     

黑龙江省五常市多目标地球化学调查与评价研究

文章对五常市开展二年多的首次多目标地球化学调查研究工作进行了总结,对多目标地球化学调查的工作方法及取得的初步成果进行了简要的介绍,针对多目标地球化学调查工作中存在的土壤元素地球化学的基准值确定方法、土壤污染检查与评价、农业生态地球化学研究等相关问题,提出了自己的见解和今后开展类似工作的具体思路。     

The city of Tyre,Lebanon and its semi-artificial tombolo

The sedimentological history of the peninsular city of Tyre, located on the southern coast of Lebanon, reflects the political events surrounding Alexander the Great's conquest of the East (332 B.C.E.). Like many other Phoenician settlements, the city was originally situated on a small, relict rocky islet, but was later connected to the mainland by an artificial causeway constructed by Alexander's troops. As a result of the causeway construction, a gigantic tombolo formed, composed of at least 10 million m³ of sediment, mostly sand. Calculations based on the present size of the land tombolo of Tyre show that the average regional yearly volume of sand drift from the south and the north for the past 2300 years was approximately 4000 m³. If the present composition of high carbonate tombolo sands is representative of the entire sand body of the tombolo, about two thirds of the mass originates from nearby beaches which formed as a result of the erosion of the Pleistocene carbonate sandstone known as “Hajar Ramli.” © 1996 John Wiley & Sons, Inc.     

The GIN Sea—A synthesis of its physical oceanography and literature review 1972–1985

A synthesis and review of the physical oceanography of the GIN Sea (Greenland, Iceland and Norwegian Seas) is presented. An accompanying bibliography is included from 1972 through 1985. Some 1986 works are also noted. Emphasis is placed on describing the GIN Sea as a major semi-enclosed basin that plays a role unique among the world's oceans: by providing a strong two-way advective exchange between the ice-covered Polar Sea and the North Atlantic Ocean and at the same time acting as the primary site for Northern Hemisphere bottom water formation. The water masses for the GIN Sea are defined, in a manner as consistent as possible with the literature. The large-scale oceanographic and meteorological factors influencing the water mass formation and circulation are described. A sample calculation of the various horizontal and vertical thermohaline-driven exchanges is given.     

The city of Matera and its ‘Sassi’ (Italy): an opportunity to broadcast geology in the European Capital of Culture 2019

Matera is an ancient city located at the top of Italy's high heel that has been anointed the European Capital of Culture 2019 and which, since 1993, has been included in the UNESCO World Heritage list. The close relationship between the urban development of the old town and its geology offers the unique opportunity to discover, in one shot, the cultural and geological history of a wonderful city that is often left out of the spotlight. As a corollary to this, the rupestrian old town of Matera and nearby areas are known also for having been the location of several movies (e.g. Bond 25 ‘No time to die’). Accordingly, media and tourists alike are showing a growing interest in Matera.     

East-Kounrad ore-field and its economic perspective

The fissure structure is the decisive controlling factor of mineralization distribution with the limits of the East-Kounrad ore-field, according to Bol'shakov. Genetically speaking, “All zones have an overlapping ‘coulisse-like’ structure of single lodes.” The totality of available structural and mineralogic data authorize predictions to the industrial prospect of single lots. The ore-field comprises several ore-bearing lots: the Geophysical lot, the South lot, the North lot, and the Wol'fram lot. The strengthening and broadening of the mineral background is possible through development of these adjacent areas of the East-Kounrad deposit. — A.W. Bellais     

Heterogeneity in the mantle—its creation, evolution and destruction

Small-scale seismic heterogeneity exists at different levels in the lower mantle, and is detected by methods that analyze scattered–not direct–energy from natural and artificial sources. Its vertical distribution, association with subduction, and its ≤ 10-km characteristic scale length strongly suggest that it is chemical/petrological in nature and originally created by melting and differentiation during mid-ocean ridge formation. What is of interest is that the scale lengths of both upper and lower mantle seismic heterogeneity are similar, which supports the view of a common origin explored here. Unlike the lower mantle however, which is broadly homogeneous in structure, the upper mantle contains things that trap and impede the dispersal and re-mixing of heterogeneity: continental crust, lithosphere and cratonic roots. These probably control the depths, the longevity and the age of heterogeneities at shallow mantle levels, and suggest that heterogeneities observed in continental mantle lithosphere are probably old, trapped by the process that grows continental roots. Alternatively, if crustal heterogeneity is controlled by the details of a magmatic process, it must either be somehow continually renewed, for which there is no recognizable surface expression, or it must be depleted over time and the present is a time when, by luck, we may still witness it.     

The economic impact of the port of Liverpool on the economy of Merseyside — Using a multiplier approach

Liverpool developed round the Port which brought prosperity to the region dating from the 18th century. Over the last twenty years, however, changes in trading patterns and cargo-handling methods have had a distinct and drastic impact upon the Port. Today it is struggling to compete with South and East coast rivals. Its economic impact on the local economy is also declining. Through examining activity linked with the Port it was found that (a) jobs totally dependent upon the Port number less than 15,000, (b) firms supplying the Port are generally only dependent upon it for an extremely small proportion of their total turnover and (c) the Port's customers, which tend to be located in the North West, West Midlands and Yorkshire-Humberside, are decreasing in number and are frequently constrained by shipping companies for their choice of port.     

The 2014 Northern Thailand Mw 6.1 Earthquake and its Seismogenic Tectonics

On May 5, 2014, an earthquake with a magnitude of Mw 6.1 (the largest earthquake in Thailand so far) occurred in Chiang Rai of the Golden Triangle area in northern Thailand. We had an opportunity to conduct field survey immediately after the earthquake. Serious damage to buildings and casualties of lives were observed, and the estimated Maximum Mercalli Intensity (MMI) of the earthquake is VIII (evaluated according to the MMI scale of the Chinese Standard). No long continuous ground ruptures were produced during the earthquake,??but in the epicenter (commonly within MMI VIII extent), massive small linear ruptures (usually several tens of meters long) developed and displayed intriguing structural features, offsetting many roads several centimeters left laterally on NE trending cracks or offsetting right laterally on NW trending ones. The focal mechanism solution of earthquake shows that this is a pure strike-slip event, and two nodal planes in NW and NE directions had the same motion senses respectively as those of breakage associated with the earthquake. The long axis of the isoseismals and aftershock distributions are in NE direction,which is consistent with the strike of Luang Namtha fault. The 230-km-long Luang Namtha fault which starts from the border of China and Laos, runs through northern Laos, and terminates at Chiang Rai of Thailand is predominated by left-lateral strike-slip and active in late Quaternary, and two earthquakes over Ms 6.0 occurred along the fault in 1925 and 2007 respectively. This Mw 6.1 earthquake occurred at the southwestern end of the fault. All related features such as evident structural rupturing, elongated orientation of MMI and aftershock distribution,as well as the location of the epicenter,suggest that the Luang Namtha fault may be responsible for the 2014 Northern Thailand earthquake.     

The Levantine Basin—crustal structure and origin

The origin of the Levantine Basin in the Southeastern Mediterranean Sea is related to the opening of the Neo-Tethys. The nature of its crust has been debated for decades. Therefore, we conducted a geophysical experiment in the Levantine Basin. We recorded two refraction seismic lines with 19 and 20 ocean bottom hydrophones, respectively, and developed velocity models. Additional seismic reflection data yield structural information about the upper layers in the first few kilometers. The crystalline basement in the Levantine Basin consists of two layers with a P-wave velocity of 6.0–6.4 km/s in the upper and 6.5–6.9 km/s in the lower crust. Towards the center of the basin, the Moho depth decreases from 27 to 22 km. Local variations of the velocity gradient can be attributed to previously postulated shear zones like the Pelusium Line, the Damietta–Latakia Line and the Baltim–Hecateus Line. Both layers of the crystalline crust are continuous and no indication for a transition from continental to oceanic crust is observed. These results are confirmed by gravity data. Comparison with other seismic refraction studies in prolongation of our profiles under Israel and Jordan and in the Mediterranean Sea near Greece and Sardinia reveal similarities between the crust in the Levantine Basin and thinned continental crust, which is found in that region. The presence of thinned continental crust under the Levantine Basin is therefore suggested. A β-factor of 2.3–3 is estimated. Based on these findings, we conclude that sea-floor spreading in the Eastern Mediterranean Sea only occurred north of the Eratosthenes Seamount, and the oceanic crust was later subducted at the Cyprus Arc.     

The age of the Cretaceous Santana Formation fossil Konservat Lagerstätte of north-east Brazil: a historical review and an appraisal of the biochronostratigraphic utility of its palaeobiota

This paper is concerned with the famous fossil-bearing carbonate concretions of the Romualdo Member of the Santana Formation Konservat Lagerstätten of north-east Brazil. This palaeontologically important horizon was first dated as Cretaceous by the French palaeoichthyologist Louis Agassiz on the basis of fish fossils obtained by Bavarian explorers Spix and Martius between 1817 and 1820 and Scottish botanist and explorer George Gardner between 1836 and 1841. Gardner equated the concretion level with the English Albian ‘Upper Greensands’ on the basis of an imagined similarity of stratigraphic sequence with that of the Isle of Wight, southern England. Since then high precision dating of this remarkable deposit has proved elusive and the concretion-bearing part of the Santana Formation has been variously dated as early Late Cretaceous or late Early Cretaceous. Attempts at greater precision over the last 30 years have cited its age variously as Aptian, Albian or possibly Cenomanian, but few reliable data have been presented to support these dates.