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1.
Durbar RAY Dalayya KOTA Pranab DAS L. Surya PRAKASH V.D. KHEDEKAR Anil L. PAROPKARI Abhay V. MUDHOLKAR 《《地质学报》英文版》2014,88(1):213-225
An extinct hydrothermal barite-silica chimney from the Franklin Seamount of the Woodlark Basin, in the southwestern Pacific Ocean, was investigated for mineral distribution and geochemical composition. Six layers on either side of the orifice of a chimney show significant disparity in color, mineral assemblage and major element composition. Electron microscope(SEM) images reveal that the peripheral wall of the chimney is composed of colloform silica, suggesting that incipient precipitation of silica-saturated hydrothermal fluid initiated the development of the chimney wall. Intermediate layers, between the exterior wall and the inner fluid-orifice, dominate with barite and sulfides. Low Sr-to-Ba ratios(SrO/BaO = 0.015–0.017) indicate restricted fluid-seawater mixing, which causes relatively high-temperature formation of the intermediate layers. Whereas the innermost layer bordering the chimney orifice is characterized by more silica and a higher Sr-to-Ba ratio(SrO/BaO = 0.023), could have formed due to a paragenetic shift from a high-temperature active phase to a cooler waning stage of formation. A paragenetic shift is also probably responsible for the change in mineral formation mechanism that resulted in the textural variation of barite and colloform silica developed during different growth phases of this barite-silica chimney. 相似文献
2.
Hg and As Minerals in Fluid Inclusions from the Williams Mine,Hemlo,and Their Genetic Implications 总被引:1,自引:0,他引:1
卢焕章 《中国地球化学学报》2002,21(1):1-18
The Hemlo mineralization is enigmatic compared to general Archean lode gold deposits based on the fact that is characterized by an exotic mineralogy containing elements such as As,Hg,Sb,Ba,V and Mo.The genetic concepts range from syngenetc to epigenetic types of mineralization.This reconnaissance study was designed to examine the relationshp of Hg-As minerals with respect of fluid inclusions in the Williams mine(formerly known as the Page Williams mine)covering the A and C ore zones. 相似文献
3.
《Geoforum》2017
REDD+ is a global scale climate change mitigation program aiming at creating financial values for carbon stored in forests. According to the proponents, REDD+ is an effective, efficient, and equitable mechanism for reducing emissions from deforestation and forest degradation. Some scholars question this assumption, and some call for further analysis to understand how REDD+ can contribute to economic, environmental, and social goals, and what are the synergies and trade-offs between them. The purpose of this paper is to contribute to the debate about whether REDD+ projects can be brought to accommodate economic (efficiency), environmental (effectiveness), and social (equity) concerns at the same time by drawing on own field results from a REDD+ project in Cambodia. The paper follows three tracks. The first is to develop and explain the conceptual and analytical framework for our empirical investigations. The second is to explain the field results. The third track is to discuss what general lessons can be learnt. Our case illustrates some of the mechanisms that are likely to work against the willingness and ability of REDD+ projects to ensure local people’s net-gains, and the risk that effectiveness and equity will suffer if REDD+ projects rely solely on the private market. Our case thus indicates a tension between the objectives of creating financial value from carbon stored in trees through the private market, and environmental and social equity concerns. However, we call for more comparative studies of REDD+ projects, and hope our conceptual framework can assist such studies. 相似文献
4.
In this research, a float-sink test was applied to a Late Permian high-sulfur coal collected from Pu’an coalfield, Southwest in Guizhou, China. To investigate the occurrence modes and the mobility of various trace elements, as well as the cleaning potential of some harmful elements in density separation, coal quality parameters and concentrations of 46 elements of 7 density fractionated samples were determined and statistically analyzed. Results show that larger size and higher density fractions have higher total sulfur content and ash yield than the smaller and lower ones. In fact, most (74.39 %) of the total sulfur occurs in the inorganic matter. Affinity and correlation analysis show that Mo and Ni have apparently strong organic affinity, whereas Rh, Cs, Sr, Co, Nb, Zr, V, Ga, Sc, Be, Ge, Hf, Th, U, Ag, As, In, Cu, Cd, Ta, Li, TI, and Ba are mostly in the heavy fractions. Rare earth element (REE) patterns for the seven density fractions present good uniformity and show that they are of right-inclined pattern type characterized by Light REE (LREE, La ~ Eu) enrichment relative to Heavy REE (HREE, Gd ~ Lu) and pronounced negative δ Eu anomalies. This suggests that REE was mainly derived from basalt-weathered materials. LRREE/HREE ratio variations reveal that LREE has stronger affinity with the organic matter relative to the HREE, while high LRREE/HREE in heavy fractions may be related to pyrite. Supposing the maximum sulfur content of the cleaned coal is 1.00 %, the theoretical removal ratios of Co, TI, and Ba are as high as 90.94, 93.73, and 92.29 %, respectively, while those of As, Ni and Mo are only 56.33, 48.85, and 45.05 %, respectively. As these figures change with different maximum sulfur contents required for the cleaned coal, not only the decrease of sulfur and ash in coal washing, but also the mobility of some harmful trace elements should be taken into consideration. 相似文献
5.
Guichun Liu Zaibo Sun Jianwei Zi M.Santosh Tianyu Zhao Qinglai Feng Guangyan Chen Xiaomei Nie Jing Li Shitao Zhang 《地学前缘(英文版)》2021,12(5):281-297
An early Paleozoic Proto-Tethys ocean in western Yunnan has long been postulated although no robust geological evidence has been identified.Here we investigated the recently-identified Mayidui and Wanhe ophiolitic melanges in SW Yunnan,which occurs in a N-S trending belt east of the late Paleozoic Changning-Menglian suture zone.The ophiolites consist mainly of meta-basalts(amphibole schists),meta-(cumulate) gabbros and gabbroic diorites,and meta-chert-shale,representing ancient oceanic crust and pelagic and hemipelagic sediments,respectively.Six samples of gabbros and gabbroic diorites from 3 profiles(Mayidui,Kongjiao and Yinchanghe) yielded zircon U-Pb ages between 462±6 Ma and 447±9 Ma,constraining the formation of the Mayidui and Wanhe ophiolites to Middle Ordovician.Gabbros from the Mayidui and Kongjiao profiles share similar geochemical characteristics with affinities to tholeiitic series,and are characterized by depleted to slightly enriched LREEs relative to HREEs with(La/Sm)_N=0.69-1.87,(La/Yb)_N=0.66-4.72).These,along with their predominantly positive wholerock ε_(Nd)(t) and zircon ε_(Hf)(t) values,indicate a MORB-like magma source.By contrast,the meta-mafic rocks from the Yinchanghe profile show significantly enriched LREEs((La/Sm)_N=0.97-3.33,(La/Yb)N=1.19-14.93),as well as positive whole-rock ε_(Nd)(t) and positive to negative zircon ε_(Hf)(t) values,indicating an E-MORB-type mantle source.These geochemical features are consistent with an intra-oceanic setting for the formation of the Mayidui-Wanhe ophiolites.Our data,integrated with available geological evidence,provide robust constraints on the timing and nature of the Mayidui-Wanhe ophiolitic melange,and suggest that the ophiolites represent remnants of the Proto-Tethys Ocean,which opened through separation of the Indochina and Simao blocks from the northern margin of Gondwana before the Early Cambrian,and evolved through to the Silurian. 相似文献
6.
正The most of high/ultrahigh-pressure(HP/UHP)terranes of the world are characterized by the occurrence of numerous pods,lenses or layered blocks of eclogite and amphibolites(e.g.O’Brien,1997;Elvevold and Gilotti,2000;Zhang et al.,2003;and references there in).Field and petrological features suggest that amphibolites should 相似文献
7.
Paula C. Ugalde Calogero M. Santoro Eugenia M. Gayo Claudio Latorre Sebastin Maldonado Ricardo De Pol‐Holz Donald Jackson 《Geoarchaeology》2015,30(4):352-368
Archaeological sites composed only of surficial lithics are widespread in arid environments. Numerical dating of such sites is challenging, however, and even establishing a relative chronology can be daunting. One potentially helpful method for assigning relative chronologies is to use lithic weathering, on the assumption that the most weathered artifacts are also the oldest. Yet, few studies have systematically assessed how local environmental processes affect weathering of surficial lithics. Using macroscopic analyses, we compared the weathering of surficial lithic assemblages from seven mid‐to‐late Holocene archaeological sites sampled from four different microenvironments in the Atacama Desert of northern Chile. Changes in polish, texture, shine, and color were used to establish significant differences in weathering between two kinds of locations: interfluves and canyon sites. Lithics from interfluve sites were moderately to highly weathered by wind and possessed a dark coating, whereas canyon lithics were mildly weathered despite greater exposure to moisture, often lacked indications of eolian abrasion, and lacked dark coatings. Our results show that lithic weathering can be used as a proxy for relative age, but only after considering local environmental factors. The power of such chronologies can be improved by combining archaeological, paleoenvironmental, geomorphological, and taphonomic data. 相似文献
8.
Inherited zircons from S-type granites provide exceptionally good insight into the isotopic heterogeneity of their sources.
Zircons from four samples (one granite, two granodiorites, one granodioritic enclave) of Pan-African S-type granite of the
Cape Granite Suite (c. 540 Ma) have been the subject of a laser LA-ICP-MS zircon U/Pb study to determine emplacement ages
and inheritance. Zircons from three of these samples (2 granodiorites and 1 granodioritic enclave) were also analysed for
Hf isotopes by LA-MC-ICP-MS. Ages of inherited cores range from 1,200 to 570 Ma and show Hafnium isotope values (εHf,t
) for the crystallisation age (t) of the different cores that range from −14.1 to +9.1. Magmatic zircons and magmatic overgrowth with concordant spot ages
between ca. 525 and ca. 555 Ma show a similar range of εHf,t
, between −8.6 and +1.5, whilst εHf values calculated at 540 Ma (εHf,540) for inherited cores range from −15.2 to +1.7. Thus, our results show that the time evolved εHf arrays of the inherited cores overlap closely with the εHf range displayed by the magmatic rims at the time of crystallisation of the pluton. These similarities imply a genetic relationship
between magmatic and inherited zircons. Within the inherited cores, four main peak ages can be identified. This, coupled with
their large Hf isotopic range, emphasises that the source of the granite is highly heterogeneous. The combination of the U/Pb
zircon ages ranges and Hf isotope data implies that: (1) The source of S-type granite consists of crustal material recording
several regional events between 1,200 and 600 Ma. This material records the recycling of a much older crust derived from depleted
mantle between 1.14 and 2.02 Ga. (2) The homogenisation of Hf isotopic variation in the magma acquired through dissolution
of the entrained zircon, via mechanical mixing and/or diffusion between within the granite was particularly inefficient. (3)
This evidence argues for the assembly of the pluton through many relatively small magma batches that undergo rapid cooling
from their intrusion temperature (ca. 850°C) to background magma chamber temperature that is low enough to ensure that much
of the magmatic zircon crystallised rapidly (>80% by 700°C). (4) There is no evidence for the addition of mantle-derived material
in the genesis of S-type Cape Granite Suite, where the most mafic granodiorites are strongly peraluminous, relatively low
in CaO and K2O rich. Interpreted more widely, these findings imply that S-type granites inherit their isotopic characteristic from the
source. Source heterogeneity transfers to the granite magma via the genesis of discrete magma batches. The information documented
from the S-type CGS zircons has been recorded because the individual batches of magma crystallised the bulk of their magmatic
zircon prior to mechanical or diffusional magma homogenisation. This is favoured by zirconium saturation in the magma shortly
after emplacement, by partial dissolution of the entrained zircon fraction, as well as by the intrusion of volumetrically
subordinate magma batches into a relatively cool pluton. Consequently, evidence recorded within inherited cores will most
likely be best preserved in S-type granite plutons intruded at shallow depths. Other studies that have documented similar
εHf arrays in magmatic zircons have interpreted these to reflect mixing between crustal- and mantle-derived magmas. This study
indicates that such arrays may be wholly source inherited, reflecting mixing of a range of crustal materials of different
ages and original isotopic signatures. 相似文献
9.
Concentrations of As, Ba, Co, Cr, Cu, Mn, Ni, Pb, V, and Zn in campus dust from kindergartens and elementary schools in Xi’an, China, were analyzed using X-ray fluorescence spectrometry and heavy metal contamination levels were assessed based on the geoaccumulation index (I geo), enrichment factor (EF) and numero synthesis pollution index (NSPI). The results indicate that, in comparison with Shaanxi soil, dust samples have elevated metal concentrations as a whole, except for V, Mn, Ni, and As. The assessment results of I geo and EF indicate that V, Mn, Ni, and As in campus dust are uncontaminated, while Ba and Cr are uncontaminated to moderately contaminated, and Co, Cu, Pb, and Zn are moderately to strongly contaminated. The NSPI results show that most dust samples presented heavily contaminated by heavy metals. More attention should be paid to heavy metal contamination of campus dust from kindergartens and elementary schools of Xi’an. 相似文献
10.
正Pseudosection modeling for the garnet amphibolite samples from the Western Dabie Mountains show they have experienced similar HP metamorphic evolution with that of the adjected eclogites.The common assemblage of 相似文献
11.
This paper explores the personal narratives of 12 women members of the Heiveld, a rooibos1 producer cooperative in the Northern Cape province of South Africa. It contributes to the emerging literature in geography and allied disciplines on so-called ‘alternative economies’, the aims of which often include the conceptual re-location of agency from the capitalist system to the realm of the human. This work suggests that human development – both individual and collective – is central to the success and indeed the alterity of alternative economies. The Heiveld members’ narratives support these ideas, in particular through their accounts of the importance of autonomous work and the significance of learning from and with others. We argue, however, that these narratives also foreground a theme that tends to be neglected in the alternative economies literature – that of consumption and the possession of material things. Our interviewees repeatedly emphasise buying and owning things as being among the most meaningful outcomes of alternative economic activity. They see great value both in having their own money, homes, and furnishings, and in being able to give to others. Through an analysis of the reciprocal, meaningful relationships between these women and everyday objects, we suggest that consumption is not opposed to human development but can be part of it. More attention should therefore be paid to the ways in which tangible, material things help constitute the more commonly researched, intangible benefits of alternative economic participation, such as empowerment, dignity, knowledge-sharing and care for others. 相似文献
12.
Previous studies have suggested that coal from the 1891 shipwreck of a collier off Victoria, BC, Canada is responsible for elevated parent (unsubstituted) PAH concentrations in sediments near deep marine outfalls from Esquimalt and Victoria in the Strait of Juan de Fuca. To resolve this question, we analysed a comprehensive suite of resolved and unresolved complex mixture (UCM) alkanes, tricyclic terpane, hopane and sterane biomarkers, and parent and alkyl polycyclic aromatic hydrocarbons (PAHs) in samples of coal, wastewater and sediments. Composition patterns, principal components analysis (PCA) models and PAH and biomarker ratios all indicate that coal from the collier does not make a dominant contribution to any sediment sample. Mass balance calculations based on the n-C24 content and 24/4 tetracyclic terpane to 26/3R tricyclic terpane ratio in coal provide a particularly good match between predicted and observed alkyl PAH concentrations for sediments with high alkyl naphthalenes and phenanthrene/anthracenes and low UCM, but the predicted coal contribution substantially underestimates the measured parent PAHs for all sediment samples. Methylbenz[a]anthracene/chrysene profiles for sediments with a dominance of parent PAHs are very close to coal tar, with a marked predominance of methylbenz[a]anthracenes and the possible 10-methylbenz[a]anthracene as a major constituent, while the methylchrysenes predominate in coal. Hence, coal from the collier could account for most alkyl PAHs in the sediments, but dredged sediment containing pyrolised coal waste from a former coal gas plant in Victoria Harbour is a more likely source for the samples with elevated parent PAHs. PAH ratios indicate that these sources are superimposed on combustion PAHs introduced by a combination of atmospheric deposition and delivery via stormwater and the outfalls. Parent PAH distributions also suggest that PAHs in wastewater that originate from oils and soot in liquid fossil fuel combustion are dispersed and degraded, while the larger wood char particles (containing PAHs more protected from degradation) settle closer to the outfalls. Overall, results suggest that PAHs have predominant sources in wood combustion, coal and possibly coke, with a likelihood of much lower bioavailability than would be expected from wastewater dominated by oils and soot from vehicle combustion. 相似文献
13.
S?awomir Ilnicki 《International Journal of Earth Sciences》2012,101(5):1253-1272
Amphibolites from the Szklarska Por?ba hornfels belt (northern part of the Karkonosze-Izera Massif) represent rocks of alkali-basalt composition metamorphosed during Variscan times. Despite the intense thermal influence of the Karkonosze granite superimposed on the effects of regional amphibolite-facies metamorphism, the geochemical affinities of the Szklarska Por?ba amphibolites are well preserved. They are similar to alkaline OIB basalts derived from an enriched (undepleted) sub-lithospheric source in the garnet stability field at depths ca 80–120?km. Trace-element characteristics and geochemical modelling indicate that the source was not modified by metasomatism in a supra-subduction zone or by alkali (silicate, carbonatitic) infiltration. Subsequent intra-crustal fractional crystallization involved olivine and clinopyroxene, and subordinate spinel and, presumably, plagioclase. The chemical composition of the rocks is most similar to that of modern magmas generated in an extensional setting (intra-continental rift). Neither geochemical characteristics nor estimated mantle temperatures only slightly higher than those of ambient mantle convincingly attest to the involvement of deep-mantle plume activity. Instead, decompression melting of passively upwelling asthenosphere beneath opening fractures in fragmented lithosphere is invoked. The origin of the amphibolite protolith was presumably associated with the Early Palaeozoic rifting of northern Gondwana, well documented throughout the Karkonosze-Izera massif. Locally rifting must have ceased earlier (immature rift) as reflected by mafic dykes exposed in the northern part of the massif, i.e., in the Szklarska Por?ba hornfelses, and by the Izera gneisses and the Stara Kamienica metapelites. A passive rift system controlled by lithosphere extension provides a plausible explanation for the origin of mafic rocks in the Karkonosze-Izera Massif and sheds light on possible mechanisms involved in the break-up of Gondwana. 相似文献
14.
İbrahim Uysal Mahmud Tarkian M. Burhan Sadiklar Federica Zaccarini Thomas Meisel Giorgio Garuti Stefanie Heidrich 《Contributions to Mineralogy and Petrology》2009,158(5):659-674
Ultramafic rocks around the city of Muğla in SW Turkey are represented by mantle peridotites depleted to various degrees,
ranging from cpx-rich harzburgites to depleted harzburgite and dunite. Cpx-rich harzburgites are thought to be the residua
left after extraction of MORB-type basalt, from which high-Al chromitite [49.2 < Cr# = 100 × Cr/(Cr + Al) < 53.5] crystallised
with a higher proportion of 187Os/188Os (average of 0.1361). However, depleted harzburgites are assumed to be the residua left after extraction of hydrous boninitic
melt produced by second stage partial melting of already depleted mantle due to a subducting slab, from which high-Cr chromitites
(64.2 < Cr# < 85.9) with lower and heterogeneous 187Os/188Os ratio (average of 0.1324) were crystallised as a result of melt–rock interaction in a supra-subduction environment. Dunites
around the chromite deposits are considered to be the product of melt–peridotite interaction. Most of the chromitites contain
high-Cr chromite and display enrichment in IPGE (Os, Ir, Ru) over PPGE (Rh, Pt, Pd), with PGE concentrations between 61 and
1,305 ppb. Consistently, laurite-erlichmanite series minerals with various Os concentrations are found to be the most abundant
PGM inclusions in chromite. Os–Ir–Ru alloy, irarsite, and kashinite, as well as Pt–Fe alloy and Pt-oxide, which are not common
in ophiolitic chromitites, were also detected as magmatic PGM inclusions. Pentlandite, millerite, and, rarely heazlewoodite
form the magmatic inclusions of base-metal sulphide. The presence of olivine and clinopyroxene, as well as hydrous silicate
inclusions such as amphibole and phlogopite, in high-Cr chromitite supports the idea that high-Cr chromitites were formed
in a supra-subduction environment. 相似文献
15.
Angelos Mavromatidis 《International Journal of Earth Sciences》2008,97(3):623-634
Seismic reflection profiles indicate the compressive nature of the structural style associated with the major uplift events
in the Cooper–Eromanga Basins. Inversion geometries and reactivated features attest to a period of compression during Late
Triassic–Early Jurassic times. In the Eromanga Basin, compressional structural styles associated with Late Cretaceous–Tertiary
are apparent. Many of the Late Cretaceous–Tertiary structures coincide with exhumation highs in Late Cretaceous–Tertiary times.
The two-layer lithospheric compression model is considered as the most complete explanation of both the uplift of areas subject
to compression and crustal thickening, and of the regional uplift of areas not subject to any apparent Late Cretaceous–Tertiary
compression. In the model, compression and thickening in the lower lithosphere is decoupled and laterally displaced from that
in the upper crust. Thickening of the mantle lithosphere without thickening of the overlying crust can account for the initial
subsidence then uplift of not inverted platform areas. The opening of the Tasman Sea and the Coral Seas can lead to stress
transmission in the interior of the continent. These stresses are likely to generate uplift but cannot explain the distribution
of uplift in areas not subject to compression. 相似文献
16.
《Tectonophysics》1999,301(1-2):35-60
The Solomon Islands are a complex collage of crustal units or terrains (herein termed the `Solomon block') which have formed and accreted within an intra-oceanic environment since Cretaceous times. Predominantly Cretaceous basaltic basement sequences are divided into: (1) a plume-related Ontong Java Plateau terrain (OJPT) which includes Malaita, Ulawa, and northern Santa Isabel; (2) a `normal' ocean ridge related South Solomon MORB terrain (SSMT) which includes Choiseul and Guadalcanal; and (3) a hybrid `Makira terrain' which has both MORB and plume/plateau affinities. The OJPT formed as an integral part of the massive Ontong Java Plateau (OJP), at c. 122 Ma and 90 Ma, respectively, was subsequently affected by Eocene–Oligocene alkaline and alnoitic magmatism, and was unaffected by subsequent arc development. The SSMT initially formed within a `normal' ocean ridge environment which produced a MORB-like basaltic basement through which two stages of arc crustal growth subsequently developed from the Eocene onwards. The Makira terrain records the intermingling of basalts with plume/plateau and MORB affinities from c. 90 Ma to c. 30 Ma, and a contribution from Late Miocene–present-day arc growth. Two distinct stages of arc growth occurred within the Solomon block from the Eocene to the Early Miocene (stage 1) and from the Late Miocene to the present day (stage 2). Stage 1 arc growth created the basement of the central part of the Solomon block (the Central Solomon terrain, CST), which includes the Shortland, Florida and south Isabel islands. Stage 2 arc growth led to crustal growth in the west and south (the New Georgia terrain or NGT) which includes Savo, and the New Georgia and Russell islands. Both stages of arc growth also added new material to pre-existing crustal units within other terrains. The Solomon block terrane collage records the collision between the Alaska sized OJP and the Solomon arc. Initial contact possibly first occurred some 25–20 Ma but it is only since around 4 Ma that the OJP has more forcefully collided with the Solomon arc, and has been actively accreting since that time, continuing to the present day. We present a number of tectonic models in an attempt to understand the mechanism of plateau accretion. One model depicts the OJP as splitting in two with the upper 4–10 km forming an imbricate stack verging to the northeast, over which the Solomon arc is overthrust, whilst deeper portions of the OJP (beneath a critical detachment surface) are subducted. The subduction of young (<5 Ma), hot, oceanic lithosphere belonging to the Woodlark basin at the SSTS has resulted in a sequence of tectonic phenomena including: the production of unusual magma compositions (e.g. Na–Ti-rich basalts, and an abundance of picrites); an anomalously small arc–trench gap between the SSTS and the Quaternary–Recent arc front; calc-alkaline arc growth within the downgoing Woodlark basin lithospheric plate as a consequence of calc-alkaline magma transfer along leaky NE–SW-trending faults; rapid fore-arc uplift; and rapid infilling of intra-arc basins. The present-day highly oblique collision between the Pacific and Australian plates has resulted in the formation of rhombohedral intra- and back-arc basins. 相似文献
17.
Immediately after an earthquake event, how long people survive in place using their limited resources is relatively unknown, as is the behavioural response to resource scarcity. Computer-aided personal interviews were conducted with 172 householders to examine how many days people believed they were able to shelter in place without official aid in a simulated earthquake event, taking into account not only the water, food and medicine they had stockpiled, but also the availability of less obvious sources (such as water in the hot water cylinder or food from gardens). Based on recommended daily resource allowances, after a 3-day period without aid, 46 % of people had run out of at least one of these necessary resources and this increased to 90 % of people after 7 days. After a 7-day period without official aid, there is an increase in people’s perceived willingness to (1) ask for assistance from neighbours (but a reduction in people’s willingness to offer aid to others), (2) commit less socially acceptable acts (such as breaking into an empty house to take food and water) and (3) commit unsafe acts (such as drinking unpurified water). The results are discussed with regard to particular post-disaster social behaviours and how social norms shift as people adapt to survive. 相似文献
18.
The provenance of Eocene–Oligocene turbidites from the Pindos Foreland Basin, SW Greece, has been constrained using petrographical and geochemical techniques. Modal petrographic analysis of the studied sandstones shows that the source area comprises sedimentary, metamorphic, and plutonic igneous rocks deposited in a recycled orogenic environment and in magmatic arc province. The relative proportions of the detrital components indicate that the Late Eocene–Early Oligocene sandstones of West Peloponnesus are quartz-rich and were primarily derived from granitic and metamorphic basement rocks typically of a tectonically active area. Major, trace, and rare earth element (REE) concentrations in both sandstones and mudstones complement the petrographical data indicating an active continental margin/continental island arc signature. All the samples are light REE, enriched relative to heavy REE (HREE), with flat HREE pattern and positive Eu anomalies, suggesting that the processes of intra-crustal differentiation (involving plagioclase fractionation) were not of great importance. The results derived from the multi-element diagrams also suggest an active margin character and a mafic/ultramafic source rock composition. 相似文献
19.
20.
Anton Zubrik David Šaman Soňa Vašíčková Bernd R.T. Simoneit L’udmila Turčániová Michal Lovás Josef Cvačka 《Organic Geochemistry》2009,40(1):126-134
Aliphatic diterpenes were isolated from brown coal from Handlová, Slovakia, using microwave assisted extraction of mechanically activated coal powder. The parameters of the extraction procedure were optimized to get the target compounds in high yield. The total extract was separated using adsorption chromatography. GC–MS revealed tetracyclic and tricyclic diterpanes in the aliphatic fraction; they were identified as 16α(H)-phyllocladane (83%), isopimarane (11%), 18-norisopimarane (4%), abietane (2%) and fichtelite (<0.1%). It was found that more than 2 g of the most abundant diterpane, 16α(H)-phyllocladane could be extracted from 1 kg of Handlová coal. Because of the scarcity of relevant analytical data, 16α(H)-phyllocladane was thoroughly characterized by spectroscopic and chromatographic methods. A complete set of 1H and 13C NMR data is given including their comparison with published values and ab initio calculations. EI mass and IR spectra of 16α(H)-phyllocladane are shown and discussed. Kováts retention indices measured on two common GC stationary phases are also given. 相似文献