Soil liquefaction susceptibility and hazard mapping in the residential area of Kütahya (Turkey)

This study presents the results of both field and laboratory tests that have been undertaken to assess liquefaction susceptibilities of the soils in Kütahya city, located in the well-known seismically active fault zone. Liquefaction potentials of the sub-surface materials at Kütahya city were estimated by using the geological aspect and geotechnical methods such as SPT method of field testing. And, the data obtained have been mapped according to susceptibility and hazard. The susceptibility map indicated “liquefable” and “marginally liquefable” areas in alluvium, and “non-liquefable” areas in Neogene unit for the magnitude of earthquake of M=6.5; whereas, liquefaction hazard map produced by using of liquefaction potential index showed the severity categories from “very low” to “high.” However, a large area in the study area is prone to liquefy according to liquefaction susceptibility map; the large parts of the liquefable horizon are mapped as “low” class of severity by the use of the liquefaction potential index. It can be said that hazard mapping of liquefaction for a given site is crucial than producing liquefaction susceptibility map for estimating the severity. Both the susceptibility and hazard maps should be produced and correlated with each other for planning in an engineering point of view.     

Some features of twisting of the Earth in geological history: the tectonophysical aspect

In this work some examples of “twisting” of the Earth in the geologic past are given: displacement of the northern parts of the global submeridional structures to the west relative to their southern parts; the rotation of the “geodynamic pair” of Siberia-Laurentia in the Proterozoic; sinistral displacement of the Northern Hemisphere relative to the Southern Hemisphere after the collapse of the last Pangaea; the equatorial rotation of the continental plates; oblique orientation of the global network of planetary fracturing; an inclination of the axis of submeridional compression; sinistral “beveling”; the dextral “twisting” of Venus. All these examples confirm the idea of possible sinistral “twisting” of the Earth that has been proposed by many authors. The cause of such “twisting” is unclear, although it is likely connected with the Earth’s rotation around its axis. Some of these examples show that many paleomagnetic reconstructions can be usefully discussed in a tectonophysical aspect. Moreover, in connection with this data, the development of a new scientific field, called “paleomagnetic tectonophysics”, is possible.     

Characteristics of ring seismicity in different depth ranges before large and great earthquakes in the Sumatra region

Characteristics of the seismicity in depth ranges 0–33 and 34–70 km before ten large and great (M _w = 7.0−9.0) earthquakes of 2000–2008 in the Sumatra region are studied, as are those in the seismic gap zones where no large earthquakes have occurred since at least 1935. Ring seismicity structures are revealed in both depth ranges. It is shown that the epicenters of the main seismic events lie, as a rule, close to regions of overlap or in close proximity to “shallow” and “deep” rings. Correlation dependences of ring sizes and threshold earthquakes magnitudes on energy of the main seismic event in the ring seismicity regions are obtained. Identification of ring structures in the seismic gap zones (in the regions of Central and South Sumatra) suggests active processes of large earthquake preparation proceed in the region. The probable magnitudes of imminent seismic events are estimated from the data on the seismicity ring sizes.     

Gated minds and gated lives as worlds of exclusion and fear

Three interrelated concepts about the “gatedness of life” are addressed in this essay: gated communities, gated lives, and gated minds. All are important components in understanding the places where gated communities are located within a city as well as those who live in them. Mapping these concepts is a further theme discussed.     

Dodging alligators,rattlesnakes, and backyard docks: a political ecology of sweetgrass basket-making and conservation in the South Carolina Lowcountry,USA

There is growing recognition among political ecologists of the need to examine shifting natural resource regimes and their effects on livelihoods in “First World” places. This emerging literature has variously examined the “Third World within,” the persistence of “subsistence activities” in the “First World,” and the “reterritorialization” of land tenure and access. However, much of this work has tended to focus on traditional extractive industries in the American West, indigenous claims to lands and resources in the U.S. and Canada, and non-timber resources on public lands. In contrast, we use a case study of African-American sweetgrass basket-makers, associated with the Gullah culture, in South Carolina’s lowcountry to examine the ways in which ongoing amenity-driven residential development is fundamentally reshaping resource access on private lands. Historically, basket-makers harvested the materials (primarily sweetgrass or Mulenbergia filipes) needed for their culturally important art form from accessible, rural, and privately held tracts of land in close proximity to their communities, but development pressures and changes in resident interpretation of property rights has decreased access to basket-making resources. The case is particularly illuminating, as it examines the emergence of ‘conservation subdivisions’ in the region and raises important questions about what “rural uses” and users are being conserved through responses to exurban, suburban, and urban development in formerly rural areas.     

Clinopyroxenes from metasomatized spinel-peridotite mantle xenoliths from Nemby (Paraguay): crystal chemistry and petrological implications

Summary The Nemby mantle xenoliths are represented by spinel peridotites variably affected by “metasomatic processes” in Proterozoic times (1.2–0.5 Ga). Clinopyroxene compositional variations mainly reflect variably degrees of basalt extraction and mantle “metasomatic processes”. Clinopyroxene crystal chemistry allows to estimate the equilibration pressure by V(Cell) and V(M1) relationship. The investigated clinopyroxenes yielded a pressure range of 12–18 kb. Therefore, the Nemby xenoliths are representative of about 20 km thickness of subcontinental lithospheric mantle of the South America platform at Tertiary times (ca. 46 Ma).

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Zusammenfassung Klinopyroxene aus metasomatischen Spinell-Peridotit-Mantel Xenolithen aus Nemby (Paraguay): Kristallchemie und petrologische Bedeutung Die Mantelxenolithe aus Nemby sind Spinellperidodite, die in verschiedenem Ausma? im Proterozoikum (1.2 bis 0.5 Ga) durch “metasomatische Prozesse” beeinflusst wurden. Variationen in der Zusammensetzung der Klinopyroxene lassen variable Ausma?e von Basaltextraktion und Mantelmetasomatose erkennen. Die Kristallchemie der Pyroxene erm?glicht es, den Gleichgewichtsdruck durch V(Cell) und V(M1) Beziehungen zu bestimmen. Die untersuchten Klinopyroxene zeigten Drucke im Bereich von 12 bis 18 kb. Die Nemby Xenolithe sind deshalb repr?sentativ für einen ungef?hr 20 km dicken subkontinentalen lithosph?rischen Mantel der südamerikanischen Plattform im Terti?r (ca. 46 Ma).

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Received February 1, 1999; revised version accepted November 26, 1999     

Strontium and oxygen isotopic variations in Mesozoic and Tertiary plutons of central Idaho

Regional variations in initial ⁸⁷Sr/⁸⁶Sr ratios (r _i) of Mesozoic plutons in central Idaho locate the edge of Precambrian continental crust at the boundary between the late Paleozoic-Mesozoic accreted terranes and Precambrian sialic crust in western Idaho. The r _i values increase abruptly but continuously from less than 0.704 in the accreted terranes to greater than 0.708 across a narrow, 5 to 15 km zone, characterized by elongate, lens-shaped, highly deformed plutons and schistose metasedimentary and metavolcanic units. The chemical and petrologic character of the plutons changes concomitantly from ocean-arc-type, diorite-tonalite-trondhjemite units to a weakly peraluminous, calcic to calcalkalic tonalite-granodiorite-granite suite (the Idaho batholith). Plutons in both suites yield Late Cretaceous ages, but Permian through Early Cretaceous bodies are confined to the accreted terranes and early Tertiary intrusions are restricted to areas underlain by Precambrian crust. The two major terranes were juxtaposed between 75 and 130 m.y. ago, probably between 80 and 95 m.y. Oxygen and strontium isotopic ratios and Rb and Sr concentrations of the plutonic rocks document a significant upper-crustal contribution to the magmas that intrude Precambrian crust. Magmas intruding the arc terranes were derived from the upper mantle/subducted oceanic lithosphere and may have been modified by anatexis of earlier island-arc volcanic and sedimentary units. Plutons near the edge of Precambrian sialic crust represent simple mixtures of the Precambrian wall-rocks with melts derived from the upper mantle or subducted oceanic lithosphere with r _i of 0.7035. Rb/Sr varies linearly with r _i, producing “pseudoisochrons” with apparent “ages” close to the age of the wall rocks. Measured δ ¹⁸O values of the wall rocks are less than those required for the assimilated end-member by Sr-O covariation in the plutons, however, indicating that wall-rock δ ¹⁸O was reduced significantly by exchange with circulating fluids. Metasedimentary rocks of the Belt Supergroup are similarly affected near the batholith, documenting a systematic depletion in ¹⁸O as much as 50 km from the margin of the batholith. Plutons of the Bitterroot lobe of the Idaho batholith are remote from the accreted terranes and represent mixtures of Precambrian wall-rocks with melts dominated by continental lower crust (r _i>0.708) rather than mantle. “Pseudoisochrons” resulting from these data are actually mixing lines that yield apparent “ages” less than the true age of the wall rocks and meaningless “r_i”. Assimilation/ fractional-crystallization models permit only insignificant amounts of crystal fractionation during anatexis and mixing for the majority of plutons of the region.     

Using ALSM to map sinkholes in the urbanized covered karst of Pinellas County,Florida—2. Accuracy statistics

We apply the logic of clinical epidemiological studies to quantify the accuracy of mapping sinkholes by ALSM in the 750 km² Pinellas County. By such studies, a new diagnostic procedure is tested by comparing the diagnoses in a clinical trial to diagnoses on the same patients from a more reliable, but more elaborate and expensive procedure (“gold standard” in epidemiological context). A relatively undeveloped, 65 km² focus area where we have aerial photographs that are effectively contemporaneous with the ALSM flights serves as the “clinical trial”. The xy-locations in the focus area are the “patients” in the trial. The “diagnostic test” for having “sinkhole disease” is inclusion in a database of sinkhole polygons delimited by ALSM contours (“ALSM-alone”), as detailed in Part 1. The standard of comparison (“gold standard” would be an overstatement in the absence of geophysical testing) is inclusion in a database of sinkhole outlines derived by best judgment of conjunctive interpretation of ALSM and aerial photography. GIS intersections that indicate the sensitivity and specificity of the test (ALSM-alone) are 43 and 98.3%, respectively, and, in the focus area where the prevalence of “sinkhole disease” is 4.7%, the positive and negative predictive values are 55.5 and 97.2%, respectively. Over much of the rest of the county, where only the test can be applied, the prevalence of sinkholes is sufficiently small that it cannot be determined to be any different from zero given the paucity of interpreted sinkholes (positive diagnoses) and the low specificity of the test method. The conclusion, therefore, is that contemporaneous aerial photography is essential to compile an ALSM-derived database that aims to state that the given xy-points lay inside or outside of topographic depressions in the covered karst of west-central Florida.     

Synthetic “Cooperite”, “Braggite”, and “Vysotskite” in the system PtS-PdS-NiS at 1100°C, 1000°C, and 900°C

Summary ?Results of experimental investigations in the dry system PtS-PdS-NiS at 1100°C, 1000°C, and 900°C are presented. The phases observed at 1100°C are “cooperite” and a melt, at 1000°C “cooperite”, “braggite”, and a melt and at 900°C “cooperite”, “braggite”, “vysotskite”, Ni_1−xS, and a melt. At 1100°C the maximum solubility of Ni in ideal, Pd-free “cooperite” is 2.7 atomic per cent and the Pd-content limit in Ni-free “cooperite” is 12.8 atomic per cent. At 1000°C the maximum solubility of Ni in ideal, Pd-free “cooperite” is 3.3 atomic per cent and the Pd-content in Ni-free “cooperite” is 13.7 atomic per cent. The “braggite” composition ranges from Pt_0.56Pd_0.38Ni_0.06S and Pt_0.59Pd_0.41S in a Ni-saturated and Ni-free environment respectively to Pt_0.18Pd_0.80Ni_0.02S and Pt_0.14Pd_0.86S respectively. At 900°C the maximum Ni-content in ideal Pd-free “cooperite” is 3.1 atomic per cent and the Pd-limit in Ni-free “cooperite” is 12.5 atomic per cent. The “braggite” composition ranges from Pt_0.59Pd_0.29Ni_0.12S and Pt_0.60Pd_0.40S for a Ni-saturated and Ni-free environment respectively, to Pd_0.91Ni_0.09S and PdS respectively. The Ni-content in “braggite” and “vysotskite” increases slightly with increasing Pt/Pd ratios and is higher at 900°C than at 1000°C. Comparison of experimental trends with cooperite, braggite, and vysotskite analyses from the literature implies high temperatures of formation for Pt-Pd-Ni sulphides in placers if Ni-saturation is assumed.

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Zusammenfassung ?Synthetischer ,,Cooperit”, ,,Braggit” und “Vysotskit” im System PtS-PdS-NiS bei 1100°C, 1000°C und 900°C Ergebnisse experimenteller Untersuchungen im trockenen System PtS-PdS-NiS bei 1100°C, 1000°C und 900°C werden dargestellt. Bei 1100°C sind die Phasen “Cooperit” und Schmelze, bei 1000°C “Cooperit”, “Braggit” und Schmelze und bei 900°C “Cooperit”, “Braggit”, “Vysotskit”, Ni_1−xS und Schmelze stabil. Bei 1100°C ist die maximale L?slichkeit von Ni in idealem, Pd-freiem “Cooperit” 2.7 Atomprozent und der Pd-Gehalt in Ni-freien “Cooperit” liegt bei maximal 12.8 Atomprozent. Bei 1000°C ist die maximale L?slichkeit von Ni in idealem, Pd-freien “Cooperit” 3.3 Atomprozent und der Pd-Gehalt in Ni-freien “Cooperit” liegt bei maximal 13.7 Atomprozent. Die Zusammensetzung des “Braggits” variiert zwischen Pt_0.56Pd_0.38Ni_0.06S und Pt_0.18Pd_0.80Ni_0.02S in einem Ni-ges?ttigtem und zwischen Pt_0.59Pd_0.41S und Pt_0.14Pd_0.86S in einem Ni-freien Umfeld. Bei 900°C liegt die maximale L?slichkeit von Ni in idealem Pd-freien “Cooperit” bei 3.1 Atomprozent und der Pd-Gehalt in Ni-freien “Cooperit” liegt bei maximal 12.5 Atomprozent. Die Zusammensetzung des “Braggits” variiert zwischen Pt_0.59Pd_0.29Ni_0.12S und Pd_0.89Ni_0.08S in einem Ni-ges?ttigten und zwischen Pt_0.59Pd_0.40S und PdS in einem Ni-freien Umfeld. Der Nickelgehalt in “Braggit” und “Vysotskit” nimmt mit zunehmendem Pt/Pd Verh?ltnis zu und ist bei 900°C h?her als bei 1000°C. Ein Vergleich der experimentellen Trends mit Cooperit, Braggit und Vysotskit Analysen aus der Literatur weist auf eine Hochtemperaturbildung der Pt-Pd-Ni Sulfide in Seifenlagerst?tten hin, wenn man von Nickels?ttigung ausgeht.

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Received October 1, 1998;/revised version accepted September 7, 1999     

Medium-scale maps after survey from space—The “Metric-Camera”—Experiment

Airphotos have been used for topographic survey since the Twenties. The “European Space Agency” (ESA), the “Deutsche Forschungs- und Versuchsanstalt für Luft- und Raumfahrt” (DFVLR) and “Carl Zeiss” have modified this successful technique for spacecraft and recently have tested the system over four continents. Each of these satellite photos covers a region of 189×189 km to the scale of 1∶800000 and may be enlarged to 1∶250000 or 1∶100000. Between the altitudes of 200 and 300 km, mapmaking or-revision seems to be economic in zones or in countries, where existing maps are of minor quality or outdated. In this paper, examples from deserts and semideserts in the Sudan are presented.     

Becoming “Hispanic” in the “New South”: Central American immigrants’ racialization experiences in Atlanta,GA, USA

For many migrants from Latin America, “Hispanic/Latino(a)” is an identity that they encounter in the United States with which they were unfamiliar in their home countries and must negotiate in their everyday lives in a new context. Specifically, immigrants from Central America are unlikely to see themselves as “Hispanic” or “Latino(a)” prior to living in the United States, more often identifying with their home country, city, town, village, or neighborhood. This paper draws on racialization theory and twenty-seven in-depth interviews with Central American immigrants in Atlanta, GA to examine this process of identity negotiation across the traditionally black/white racialized landscapes of a “New South” city. Interview participants adopt a racialized Hispanic identity through a complex process involving the interplay between how they think of themselves and their perceptions of how native-born Atlantans view them. The interview analysis presented herein demonstrates that although Central American immigrants actively negotiate a Hispanic racialized moniker, they do so within an urban context dominated by native-born residents whose racialized assumptions lump Spanish-speaking, brown skinned individuals into a monolithic “Mexican” category. Thus the ways in which racialized difference is constructed in contemporary Atlanta for recent Central American immigrants is very much bound up in such false presumptions of national identity and cultural group belonging.     

Identifying sources of groundwater recharge in the Merguellil basin (Tunisia) using isotopic methods: implication of dam reservoir water accounting

Thirty-two groundwater samples collected from the Merguellil Wadi basin (central Tunisia) complemented by the Haouareb dam reservoir water samples have been isotopically analysed in order to investigate the implication of the reservoir water to recharging the aquifer, and also to infer the sources, relative ages and mixing processes in the aquifer system. Plots of the stable isotopes data against the local meteoric lines of Tunis-Carthage and Sfax indicate a strong implication of the dam water noticeable up to a distance of 6–7 km. A contribution as much as 80% of the pumped water has been evidenced using isotopic mass balance. In addition, poorly distinguished water clusters in the stable isotope plots, but clearly identified in the diagrams δ¹⁸O versus ³H and ³H versus ¹⁴C, indicate various water types related to sources and timing of recharge. The isotopic signatures of the dam accounting water, the “old” and “native” recharged waters, have been evidenced in relation to their geographical distribution and also to their radiogenic isotopes (³H and ¹⁴C) contents. In the south-western part of the aquifer, mixing process occurs between the dam reservoir water and both the “old” and “native” water components.     

“[W]e do not lose our treaty rights outside the... reserve”: challenging the scales of social service provision for First Nations women in Canadian cities

Recent work in political geography has emphasised how scale plays a role in constituting relationships and identities. Historically, the Canadian federal government has taken responsibilities for social services for First Nations people on reserves, leaving this responsibility to provinces for First Nations people in cities. This constitutes First Nations women as individuals with Aboriginal rights only on reserves, and as part of mainstream society in urban areas. First Nations women have challenged the definitions of their identities embedded in these scales of service provision. In presenting alternative geographies for organising the provision of services, they demonstrate the importance of paying attention to the diversity of women’s everyday geographies in the city. This is a phrase from Vicki English’s (1993) presentation to the Royal Commission on Aboriginal Peoples, where she argues that treaty rights to housing, education, medicare and other services should not be confined to the boundaries of reserves. I use the term “First Nations” to refer to people who identify themselves as such, including people who are and are not registered pursuant to the Indian Act. By “Aboriginal peoples” I mean the descendants of the indigenous people in Canada, including First Nations people, Métis and Inuit. The Census of Canada uses the term “North American Indian” to refer to First Nations people, and I employ this terminology for clarity in some cases.

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Redox environment effect on redox sensitive elements in surface sediments of the Changjiang Estuary hypoxia zone

The grain size and element (including redox sensitive elements and terrigenous elements) concentration of surface sediments from the Changjiang Estuary hypoxia zone and its adjacent sea area were measured in this research. Based on the obtained data, the hypoxic environment’s influence on the distribution of elements in surface sediments was further studied. We believe that the “redox environment effect” greatly influences the distribution of the RSE, which reveals the “patchy enrichment pattern” offshore in the hypoxia zone, while the distribution of the terrigenous elements which shows the “stripped enrichment pattern” near shore is mainly affected by “granularity effects”. Due to the existence of the hypoxia zone of the Changjiang Estuary, the distribution of the RSE such as Mo, Cd and V in the study area exhibits the characteristics of “redox environment effects”. __________ Translated from Marine Geology & Quaternary Geology, 2007, 27(3):1–8 [译自: 海洋地质与第四纪地质]     

Earliest record of rhinocerotoids (Mammalia: Perissodactyla) from Switzerland: systematics and biostratigraphy

Earliest rhinocerotoids from Switzerland are reviewed on the basis of dental remains from the earliest Oligocene north-central Jura Molasse localities of Bressaucourt (MP21/22) and Kleinblauen (top MP22). The record in Bressaucourt is restricted to Ronzotherium and Cadurcotherium, representing Switzerland’s oldest, well-dated post-“Grande Coupure” large mammal association, the only occurrence of Cadurcotherium, and the earliest occurrence of rhinocerotoids in Switzerland. The correlation with high-resolution stratigraphy of this locality permitted a dating of the fauna to ca. 32.6 Ma, less than a million years after the “Grande Coupure” event. The rhinocerotoids of Kleinblauen are represented by Epiaceratherium, Ronzotherium and Eggysodon. With the presence of Plagiolophus ministri, they are the only well-dated Swiss post-“Grande Coupure” large mammal assemblage with the persistence of an endemic pre-“Grande Coupure” taxon. Moreover, the coexistence of Epiaceratherium magnum and E. aff. magnum could indicate a new speciation within the Epiaceratherium lineage around the top of MP22. The rhinocerotoid associations of Bressaucourt with Ronzotherium – Cadurcotherium on the western side of the southernmost Rhine Graben area, and Kleinblauen with Epiaceratherium – Ronzotherium – Eggysodon on the eastern side, respectively, reveal a possible environmental barrier constituted by the Early Oligocene Rhenish sea and its eventual connection with the Perialpine sea. This one could have separated an arid area in central-eastern France from a humid area in Switzerland and Germany. These results, combined with the repartition of similar rhinocerotoid associations in Western Europe, also give new insights into an alternative earliest Oligocene dispersal route of rhinocerotoids from Asia towards Western Europe via North Italy.     

The allochthonous genesis model about the extra-thick and high-quality coalbed in Xianfeng basin, Yunnan Province, China

An extra-thick high-quality brown coal was found to have accumulated in the Xianfeng basin in Yunnan Province, China. There are also abundant sedimentary marks of allochthonous genesis in the extra-thick coalbeds. These genesis indicators reveal a new submodel about allochthonous accumulation, which is: the long-distance river transportation of detrital plant and inorganic matter → the sedimentation of detrital plant fan delta + the hypautochthony accumulation of local lakeshore swamp peat → the autochthonous accumulation of local lacustrine peat + the sedimentation of fine inorganic matter → the mixing and transportation by flood current or weak storm flow or underwater gravity flow → the mechanical differentiation and their resedimentation between detrital plant and inorganic matter. This submodel can be called “the double accumulation of lacustrine detrital plant fan delta and underwater gravity flow” or “Xianfeng submodel”, which supplements the “allochthonous-hypautochthony lacustrine combination accumulation model” of the extra-thick coalbeds. The combination accumulation model is based on the Fuxin submodel and Fushun submodel in the Chinese Mesozoic and Cenozoic intarcontinental fault basin. Translated from Acta Sedimentologica Sinica, 2006, 24(1): 1–9 [译自: 沉积学报]     

Diamonds and eclogites of the Jericho kimberlite (Northern Canada)

We studied diamonds and barren and diamondiferous eclogite xenoliths from the Jericho kimberlite (Northern Slave craton). The majority of the diamonds are non-resorbed octahedral crystals, with moderately aggregated N (IaB < 50%, N < 300 ppm) and δ¹³C = −5 to −41‰. The diamonds belong to “eclogitic” (90% of the studied samples), “websteritic” (7%) and “peridotitic” (3%) assemblages. The Jericho diamonds differ from the majority of “eclogitic” diamonds worldwide in magnesian compositions of associated minerals and extremely light C isotopic compositions (δ¹³C = −24 to −41‰). We propose that metasomatism triggered by H₂O fluids may have been involved in the diamond formation. Multiple episodes of the metasomatism and associated melt extraction of various ages are evident in Jericho eclogite xenoliths where primary garnet and clinopyroxene have been recrystallized to more magnesian minerals with higher contents of some incompatible trace elements and to hydrous secondary phases. The model is supported by the general similarity of mineral compositions in diamondiferous eclogites to those in diamond inclusions and to secondary magnesian garnet and clinopyroxene in recrystallized barren eclogites. The ultimate products of the metasomatism could be “websteritic” diamond assemblages sourced from magnesian eclogites. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Genesis of diamonds in the lower mantle

The “forbidden” assemblage (ferropericlase + enstatite) as inclusions in diamonds has been taken as evidence to imply that these inclusions and their host diamonds formed initially in the lower mantle. Magnesite is probably the only stable carbonate at depths greater than ∼220 km. Like dehydration reactions, the reaction boundary for the decarbonation of magnesite has a positive dT/dP slope at lower pressures, which becomes negative at higher pressures, if no other phase intervenes. This reaction boundary probably intersects the geotherm between ∼900 and ∼1100 km, below which magnesite decomposes into an assemblage periclase + diamond + oxygen. Thus, ferropericlase is the most likely inclusion in diamond formed in the lower mantle. The high frequency of sole occurrence of ferropericlase in diamonds from Sao Luiz, Brazil seems to substantiate the present speculation. Received: 8 June 1998 / Accepted: 28 September 1998     

Chemodynamics of trace metal fractions in surface sediments of the Pandoh Lake,Lesser Himalaya,India

The seasonal variation in the trace metals’ concentrations (Cd, Co, Cu, Fe, Mn, Ni, Pb, and Zn) were investigated in surface sediments of the Pandoh Lake. The horizontal distribution of TC, TN, and TP reflects spatial and temporal differences in sedimentary organic production. The chemical sequential extraction of heavy metals was carried out by seven-step fractionation scheme (Leleyter and Probst in Int J Environ Chem 73:109–128, 1999). The significant concentrations of Ni and Cd were associated with “water soluble (Eua)” fraction in the monsoon and winter, respectively, while “exchangeable (Exch)” and “carbonate-bound (Carb)” fractions for Ni and Cd were abundant in winter and summer. The Cd, Cu, and Pb associated with “Exch” fraction in the summer season support their availability on exchange sites due to oxidized nature of surface sediments. Enrichment of Co, Fe, Mn, and Zn in “AFeO” fraction showed poor bioavailability, while Cd, Cu, and Mn in the monsoon, Co in the winter and summer, and Zn in the winter season showed significant “organically bound (Org)” fraction. The ANOVA was significant for chemical fractions of trace elements except “Carb” fraction of Pb and Zn and “CFeO” fraction of Pb. Factor analysis revealed that the “Eua”, “Exch”, and “Carb” fractions together control the metal enrichment of “MnO”, “AFeO”, and “CFeO” fractions in the summer season.     

Mercury in soil from the area of Dayton,Ohio

Mercury concentrations in “A-zone” soil from seventeen urban, suburban, and rural town locations in the area of Dayton, Ohio range from 0.24 to 1.50 ppm. A positive correlation is indicated between the mercury concentrations and the amount of fallout of settleable particulate matter from the air at these sites. Airborne pollution may be an important source of the element in Dayton area soils.