Concentrations of contaminants in surface water samples collected in west-central Indiana impacted by acidic mine drainage   总被引：1，自引：0，他引：1  

S. K. Allen  J. M. Allen  S. Lucas 《Environmental Geology》1996,27(1):34-37

The results of analyses of surface waters collected from a variety of locations in west-central Indiana indicate extensive contamination by acidic mine drainage. These samples had pH values as low as 2.1 and total iron concentrations as high as 1200 mg1^–1. The speciation of iron, expressed as the ratio [Fe(II)]/[Fe(III)] ranged from 0.08 to 8.27. Measured lead concentrations were as high as 811 mgl^–1. In addition, the concentrations of nitrate and sulfate ions were as high as 359 and 624 mgl^–1, respectively.  相似文献   

Data for coastal GIS: issues and implications for management     

A. E. Lucas 《GeoJournal》1996,39(2):133-142

Geographic information systems can provide easy access to large quantities of geographically-referenced data for monitoring, planning and environmental decision support for coastal applications. The dynamic and variable nature of the coastal ocean environment gives rise to data issues different than those associated with land-based GIS. This paper investigates, in particular, the use of different data, including those produced by numerical simulations or ocean models, for coastal management and is illustrated with examples from a Baltic Sea GIS implementation. Implications for the use of these data in environmental management are discussed.  相似文献   

The Thornton Beach Mammoth: Consistency of Numerical Age and Morphology     

Spencer G. Lucas 《Quaternary Research》1996,45(3):332-333

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Trace element incorporation into pyrope–grossular solid solutions: an atomistic simulation study     

W. van Westrenen  N. L. Allan  J. D. Blundy  M. Yu Lavrentiev  B. R. Lucas  J. A. Purton 《Physics and Chemistry of Minerals》2003,30(4):217-229

 We have performed atomistic computer simulations on trace element incorporation into the divalent dodecahedral X-sites of pyrope (Py — Mg₃Al₂Si₃O₁₂) – grossular (Gr — Ca₃Al₂Si₃O₁₂) solid solutions. An ionic model and the Mott–Littleton two-region approach to defect energies were used to calculate the energetics of substitution by a range of divalent trace-elements and of charge-balanced substitution by trivalent ions in the static limit. Results are compared with experimental high-temperature, high-pressure garnet-melt trace element partitioning data obtained for the same garnet solid solution to refine our understanding of the factors controlling element partitioning into solid solutions. Defect energies (U _def,f), relaxation (lattice strain) energies (U _rel), and solution energies (U _sol) were derived using two different approaches. One approach assumes the presence of one type of hybrid X-site with properties intermediate between pure Mg and Ca sites, and the other assumes discrete Mg and Ca X-sites, and thus two distinct cation sublattices. The hybrid model is shown to be inadequate, since it averages out local distortions in the garnet structure. The discrete model results suggest trace elements are more soluble in Py₅₀Gy₅₀ than in either end-member compound. Physically this is due to small changes in size of the X-sites and the removal of unfavourable interactions between third nearest neighbours of the same size. Surprisingly, depending on the local order, large trace element cations may substitute for Mg²⁺ and small trace elements for Ca²⁺ in Py₅₀Gr₅₀. These solubilities provide an explanation for the anomalous trace-element partitioning behaviour along the pyrope–grossular join observed experimentally. Received: 27 January 2000 / Accepted: 14 February 2003  相似文献   

The world energy book: David Crabbe and Richard McBride. Kogan Page, 259 pp., UK £ 12.90     

N.J.D. Lucas 《Physics of the Earth and Planetary Interiors》1979,19(4):359-360

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Oceanography and marine biology. An Annual Review: Vol. 19, edited by Margaret Barnes,Aberdeen University Press,Aberdeen, 1981. 655 pp. ISBN 0 08 028439 6. Price: £39.00     

Sir Cyril Lucas 《Marine pollution bulletin》1982,13(4):142-143

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Ecosystèmes continentaux du mésozoïque: Edited by Ph. Taquet. Mémoires de la Société Géologique de France,Nouvelle Série,LIX, Mémoire no 139, 212 pp., 300 FF     

N.J. Mateer  S.G. Lucas 《Cretaceous Research》1981,2(2):251-257

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Summer Floods in Central Europe – Climate Change Track?     

Zbigniew W. Kundzewicz  Uwe Ulbrich  Tim brücher  Dariusz Graczyk  Andreas Krüger  Gregor C. Leckebusch  Lucas Menzel  Iwona Pińskwar  Maciej Radziejewski  Małgorzata Szwed 《Natural Hazards》2005,36(1-2):165-189

In Central Europe, river flooding has been recently recognized as a major hazard, in particular after the 1997 Odra /Oder flood, the 2001 Vistula flood, and the most destructive 2002 deluge on the Labe/Elbe. Major recent floods in central Europe are put in perspective and their common elements are identified. Having observed that flood risk and vulnerability are likely to have grown in many areas, one is curious to understand the reasons for growth. These can be sought in socio-economic domain (humans encroaching into floodplain areas), terrestrial systems (land-cover changes – urbanization, deforestation, reduction of wetlands, river regulation), and climate system. The atmospheric capacity to absorb moisture, its potential water content, and thus potential for intense precipitation, are likely to increase in a warmer climate. The changes in intense precipitation and high flows are examined, based on observations and projections. Study of projected changes in intense precipitation, using climate models, for several areas of central Europe, and in particular, for drainage basins of the upper Labe/Elbe, Odra/Oder, and Vistula is reported. Significant changes have been identified between future projections and the reference period, of relevance to flood hazard in areas, which have experienced severe recent floodings.  相似文献   

Late Pleistocene and Holocene history of Lake Terrasovoje,Amery Oasis,East Antarctica,and its climatic and environmental implications   总被引：1，自引：3，他引：1  

Bernd Wagner  Holger Cremer  Nadja Hultzsch  Damian B. Gore  Martin Melles 《Journal of Paleolimnology》2004,32(4):321-339

A 5.52 m long sediment sequence was recovered from Lake Terrasovoje, Amery Oasis, East Antarctica, in order to reconstruct the regional environmental history. The basal sediments, which are dominated by glacial and glaciofluvial clastic sediments, attest to a Late Pleistocene deglaciation of the lake basin. These sediments are overlain by 2.70 m of laminated algal and microbial mats and a few interspersed moss layers. Radiocarbon dating, conducted on bulk organic carbon of 12 samples throughout the organic sequence, provides a reliable chronology since the onset of biogenic accumulation at c. 12,400 cal. year BP. Successful diatom colonization, however, was probably hampered by extensive ice and snow cover on the lake and restricted input of nutrients until 10,200 cal. year BP. A subsequent increase of nutrient supply culminated between 8600 and 8200 cal. year BP and is related to warm summer temperatures and reduced albedo in the catchment. Warm conditions lasted until 6700 cal. year BP, supporting the establishment of a diatom community. Colder temperatures from 6700 cal. year BP culminated in several periods between 6200 and 3700 cal. year BP, when high amounts of sulphur and low abundances of diatoms were deposited due to a perennial ice and snow cover on the lake. During the late Holocene, relatively warm conditions between 3200 and 2300 cal. year BP and between 1500 to 1000 cal. year BP, respectively, indicated by high accumulation of organic matter and reducing bottom water conditions, were interrupted and followed by colder periods.  相似文献   

Kinematics of the Rockland Brook Fault, Nova Scotia: Implications for the interaction of the Meguma and Avalon terranes     

Brent V. Miller  R. Damian Nance  J. Brendan Murphy 《Journal of Geodynamics》1995,19(3-4)

The Cobequid-Chedabucto fault system of northern mainland Nova Scotia represents the surface expression of the Avalon-Meguma terrane boundary, but because it is exposed at high crustal levels in the Cobequid Highlands, the fault system provides little information as to the kinematic relationships of the two terranes in this area. In the eastern Cobequid Highlands, the Rockland Brook Fault (RBF) is exposed within the more deeply eroded highlands massif and juxtaposes units of widely varying ages and lithologies. Therefore, this fault is better suited to define the nature and timing of fault movement associated with Avalon-Meguma terrane interaction.In several large Carboniferous plutons along the length of the RBF, and in previously deformed Precambrian rocks, mylonitic foliation orientations are predominantly east-west trending and mineral lineations plunge southeast. Kinematic indicators such as minor fold vergence, porphyroclast systems, asymmetric boudins, shear-band fabrics, and preferred recrystallization orientations indicate dextral shear. These data are taken to infer that the central section of the RBF is dominated by dextral strike-slip motion. Transpression occurs locally where the RBF curves into restraining bends. Kinematic data in these bends indicate top to the northwest thrusting. At the easternmost extent of the RBF, high-level brittle normal faults predominate in the locally extensional environment. The timing of RBF movement is constrained only by the ca 360 Ma granite bodies which it deforms and by the Westphalian sedimentary rocks which are affected by only the latest stages of movement.These kinematic data are consistent with previously published kinematic models for the interaction of the southern margin of the Avalon Composite Terrane with the Meguma Terrane in mainland Nova Scotia. These models suggest that regional dextral shear was accompanied by localized components of transpressional thrusting, wrench tectonism, and small-scale sedimentary basin development during Devonian to Carboniferous terrane interaction.  相似文献