On the Origin of the Carat as the Unit of Weight for Gemstones

The carat is the unit of weight for diamonds and other gemstones.It corresponds to the average weight of the seeds of a leguminous tree.What kind of tree is this?We have studied the samples from Ethiopia,Egypt,Cyprus and the United States.The tree is neither“Kuara“nor“Locust“（Robina pseudoacacia Linn.）,but rather Carob(Ceratonia Siliqua).In Ethiopia,as called by local inhabitants,“Kuara“is a species of Erythrina-E.brucei rather than E.abyssinica.As might be expected,using the seeds as a means of weighing an extremely valuable commodity is not very scientific.Before 1907,at various times and in various countries,there were at least twenty-three stan-dards for the carat ranging from 187.00mg to 215.990mg.The metric carat equal to 200mg was proposed in Paris in 1907.It was adopted in the United States on July1,1913 and now is the world-accepted standard.But in reality,the standard of the carat is still confused with respect to its usage throughout the world .This is why the author reiterates that the standard of the car-at should be integrated with the metric system.     

Analytical Model for the Palaeoenvironmental Evolution of the Nihewan Beds

In this paper, the evolutional characteristics of palaeoclimate and oxidation-reduction conditions as well asacidity-alkalinity environment are discussed by means of the step-regression, cluster, optimal partitioning andcorrelation analyses of CaCO_3, C / P_2O_5, Fe~(2+) / Fe~(3+), pH and Eh values, taking the Xiaodukou section in theNihewan basin as an example. The CaCO_3, C / P_2O_5 and pH were calculated respectively using the optimalpartitioning method. Thus five cold zones and six warm zones as well as five reduction and six oxidation zoneswere distinguished. Then the inductive method was used to produce four numerical groups: 8.10, 8.3-8.4,8.6-8.7 and 8.9-8,97. The above-mentioned results are respectively based on CaCO_3 content, C/P_2O_5 andpH values. From Fig. 3, Tables 1 and 2 it can be seen that the Nihewan Beds were formed mainly under a re-duction and slightly alkaline environment of cold climate, with pH values of 8.3-8.4. Fig. 3 shows that bed 35is approximately near the boundary between the Brunhes and Matuyama polarity epochs, 0.73 Ma in age; bed26 is roughly near the Jaramillo event (base), 0.97 Ma in age; bed 18 coincides roughly with themagnetostratigraphic boundary of 2.00 Ma (?). Bed 13 may be the Pleistocene-Pliocene boundary, 2.48 Ma inage. Thus geochemical zones Ⅰ, Ⅱ, Ⅲ and Ⅳ include respectively cold zones 1; 2 and 3; 4; and 5.     

Equation of state of magnesite for the conditions of the Earth’s lower mantle

A semiempirical equation of state was derived for magnesite under the thermodynamic conditions of the Earth’s mantle. Within experimental uncertainties, it is consistent with thermochemical, ultrasonic, X-ray, and shock-wave data at temperatures from 15 K to the melting point and pressures of up to 100–130 GPa. The following values were recommended for the isothermal bulk modulus and its pressure derivative: K _T = 111.71 GPa and K′ = 4.08. Thermodynamic analysis showed that magnesite does not decompose to periclase and CO₂ under the thermodynamic conditions of the Earth’s lower mantle and outer core.     

Degradation of Microbes for the Crude Oil Contaminants

Production and storage-transportation of crude oil can not only give rise to soil pollution but also destroy ecological environment．Degradation of microbes for oily soil was studied with the strument，Geofina Hydrocarbon Meter（GHM），by experimental analysis qualitatively and quantitatively in the paper．Analytical result showed that the crude oil could be considerably degraded by eating-oil microbes in oily soil and the number of eating-oil microbes increased while the working hours of oil-well rising．As a result，contaminated oil could be degraded more quickly by a lot of eating-oil microbes in the soil．At the same time，the degradation rate of contaminated oil increased gradually as the time went on．In addition，amount of gaseous component in the oily soil samples increased with degraded time and the microbes could selectively consume contaminated oil strongly，so biodegradation might alleviate the degree of contamination and destruction to the soil and environment in the process of oil production at oilfield．The law of oily soil degraded by microbes was investigated and some useful conclusions were drawn in the paper．     

The Principles for Discrimination of the Source Composition of Mantle-Derived Igneous Rocks and the Nature of the Mantle Source Region of the Emeishan Basalts

This paper discusses the discrimination principles. deduction and methods for probing into the source composition of mantle-derived magma. The magmatophile (incompatible) source elements are not all optimal tracers for mantle source composition. The ratios of two strong magmatophile elements (D<1) or the ratios of two trace elements with the same D value are not controlled by the formation mode and evolution degree of a magma, but maintain the characteristics of their composition in mantle source region prior to the magma formation. The ratios are related to different mantle-crust structures and dynamics. The mantle source composition of the Emeishan Basalt series is similar to that of the South Atlantic Rio Grande Rise-Walvis Ridge Basalts and Brazil continental-margin basalts. This may indicate that these basalt series might have similar source regions and tectonic environments.     

Evidence for the Lower Continental Crustal Origin of the Xihuashan Granite

The Xihuashan granite is typically representative of the tungsten-bearing granites widespread in theNanling area of South China. It was considered in the past to have been formed by partial melting of the upper continental crust, with its source rocks most probably of the Sinian or Cambrian. However, detailed REE analyses, studies of the Rb-Sr isotopic system and melting experiments of metasedimentary rocks all argue against this idea. Moreover, stable isotopic data also indicate a deep source origin for S, C, H and O. The authors thus propose a genetic concept of the lower continental crustal source of the Xihuashan granite, and point out further that tungsten deposits related to this kind of granite are linked in some way to deep-seated structure and concentrated along NNE-NE- and ENE-striking major deep fault belts above the transitional zone between mantle uplift and mantle depression.     

A Scheme of the Hierarchy for Sequence Stratigraphy

Inthelasttwodecades,sequenCestratigraphyhasbecomethecornerstoneofmodernstratigraphyandhasbeenwidelyusedbothintheexplorationofoilandgasandinthestudyofregionalgeology.Assequencestratigraphyhasextendedfromundergroundinvestigationsbyseismicmethodstooutcropstudiesbyordinary$tratigraphicapproaches,andasithasgrownintoamoreorlessmaturebranchofstratigraphicaldisciplines,theestablishmentofarelevanthierarchyofthesequencestratigraphictntSseemstohavebecomeoneoftheurgefltrequire~,especiallyasthereexistsomec…     

Degradation of Microbes for the Crude Oil Contaminants

Production and storage-transportation of crude oil can not only give rise to soil pollution but also destroy ecological environment. Degradation of microbes for oily soil was studied with the instnunent, Geofina Hydrocarbon Meter (GHM), by experimental analysis qualitatively and quantitatively in the paper. Analytical result showed that the crude oil could be considerably degraded by eating-oil microbes in oily soil and the number of eating-oil microbes increased while the working hours of oil-well rising. As a result, contaminated oil could be degraded more quickly by a lot of eating-oil microbes in the soil. At the same time, the degradation rate of contaminated oil increased gradually as the time went on. In addition, amount of gaseous component in the oily soil samples increased with degraded time and the microbes could selectively consume contaminated oil strongly, so biedegradation might alleviate the degree of contamination and destruction to the soil and environment in the process of oil product     

Geological Evidence for the Presence of the Emperor Event in China

The presence of the reversals of the geomagnetic field within the Brunhes is indicated by paleomagnetic stuides on Cenozoic volcanic rocks in the Leizhou Peninsula, loess strata and Quaternary marine sediments in the Pearl River Mouth basin in China. These regional reversals occured at 0.58±0.13 Ma, 0.45 Ma and 0.47—0.48 Ma respectively according to the results of K-Ar isotopic dating and climatostratigraphic and biostratigraphic analyses. The reversals equivalent to the Emperor Event is suggested.The reversals revealed in different regions with various lithologic characters in China prove that the Emperor Event is a global reversal event rather than a geomagnetic excursion, and its confirmation will permit a precise definition of the Middle/Late Pleistocene boundary.     

Modelling of the oxygen isotope evolution of seawater: implications for the climate interpretation of the δ18O of marine sediments

It is often argued that the δ¹⁸O value of oceanic water was maintained close to 0‰ for hundreds of millions of years, as a consequence of oxygen isotope exchange between oceanic crust and seawater. However, for several decades, the interpretation of the biosedimentary oxygen isotope record has conflicted with the igneous record because, with increasing age, a general trend of decreasing δ¹⁸O values (about 6‰) is observed in most carbonates, cherts and phosphates, especially for the Paleozoic and early Mesozoic. We developed a dynamical model of seawater-crust interaction that computes the δ¹⁸O value in these two reservoirs as function of time. This model takes into account the continuous production of crust at oceanic ridges, its expansion rate, the permeability profile with space and time, the mineralogical mode of the crust, and the kinetics of oxygen isotope exchange between rock-forming minerals and seawater. The model indicates that the δ¹⁸O value of seawater may vary by ±2‰ with a time response ranging from 5 to 50 Ma for expansion rates of 1 to 10 cm.a⁻¹. The variation of ±2‰ is fixed by both integrated water-rock ratio and closure time of the seawater-crust system by sediments. Variations in the oxygen isotope ratio of seawater through time have important implications for the interpretation of the systematically low δ¹⁸O values of pre-Jurassic marine sediments. According to our model, marine paleotemperatures could be up to 10°C lower than those expected when applying the classical hypothesis of an ice-free ocean with a δ¹⁸O value of −1‰.     

Field-scale evaluation of the chemical–biological stabilization process for the remediation of hydrocarbon-contaminated soil

Developing countries face the challenge of growing their economy while reducing the negative environmental impacts of industry, thus requiring treatment technologies that are economical and effective. One recent technology developed in the tropical part of Mexico for the remediation of petroleum-contaminated soil was tested in this scale-up project at an industrial level, whereas previously it had only been tested at laboratory scale; 150 m³ of bentonitic mud, contaminated with weathered hydrocarbons (3.4°API) at ~50,000 ppm, was treated with 4 % Ca(OH)₂, 4 % organic amendment, and a fine-root tropical grass. Hydrocarbons in soil and in leachates, as well as pH, and acute toxicity (Microtox) were monitored for 28.8 months. At the end of the study, basal respiration, root density, and earthworm toxicity were also measured. The hydrocarbon concentration in soil was reduced to 45 %, and toxicity was eliminated. Hydrocarbons in leachates were reduced to ~1 mg/l, safe for human consumption. The pH adjustment depended on low soil moisture and was stabilized at 7.1. Intense revegetation resulted in good root density, within 90 % of nearby uncontaminated soil under pasture. Basal respiration was increased to levels comparable to uncontaminated tropical soils with agricultural use, pasture and gallery forest. At an industrial scale, strict moisture control was necessary for good pH stabilization. By controlling these conditions and applying this novel treatment process, it was possible to transform a heavily contaminated geological material into a non-toxic, fertile, soil-like substrate capable of maintaining a complete vegetative cover and microbial activity comparable to similar soils in a tropical environment.     

Continental flood basalts of the Huashan Group,northern margin of the Yangtze block – implications for the breakup of Rodinia

It is generally accepted that Neoproterozoic extension and dispersal of the supercontinent Rodinia was associated with mantle plume or superplume activities. However, plume-generated contemporaneous continental flood basalts (CFBs) have rarely been identified. In this study, we present geochronological and geochemical evidence for the basalts from the Liufangzui Formation of the Huashan Group in the Dahongshan region of east-central China. A representative sample yields a SHRIMP U–Pb zircon age of 824 ± 9 Ma, interpreted as the crystallization age of the rocks. Geochemically, these basalts belong to the subalkaline tholeiite series and display slight enrichments in light rare earth elements (LREE) and varying degrees of deficiency of high field strength elements (HFSE) such as Nb, Ta, and Ti. This pattern is very similar to that of CFBs from the Bikou Group and Tiechuanshan Formation in the northwestern Yangtze block in China and Siberia in Russia. The basaltic magmas underwent partially-fractional crystallization during ascent, but were not intensely influenced by crustal contamination. The characteristic element ratios and negative Hf isotopic analyses (?_Hf(t) = ?6.6–2.6) in zircons indicate that the parental magmas of the basalts might have been derived from an enriched lithospheric mantle rather than from the depleted mantle such as normal mid-ocean ridge basalts (N-MORBs). The geochemical signatures and regional geological characteristics show that these basalts were formed along intraplate continental rifts rather than in island arcs or ocean basins. Considering the coeval basic volcanic rocks in South China, we propose that these Huashan Group basalts represent the remnants of plume-generated CFBs and have close spatiotemporal ties with a coeval basic igneous province in Australia. Our results support the Neoproterozoic location of the South China block adjacent to southeastern Australia in the reconstruction model of the supercontinent Rodinia.     

Application of the coupled TOPSIS–Mahalanobis distance for multi-hazard-based management of the target districts of the Golestan Province,Iran

Natural Hazards - This study is aimed at producing an improved ranking method by coupling the technique for the order of preference by similarity to ideal solution (TOPSIS) and Mahalanobis distance...     

Geochronology of the Birim Supergroup of the West African craton in the Wa-Bolé region of west-central Ghana: Implications for the stratigraphic framework

The Birim rocks of the West African craton comprise belts of greenschist- to amphibolite-grade gneiss and schist, and subparallel basins of greenschist-grade phyllite of volcaniclastic and epiclastic origin, which were intruded by igneous rocks. The granitoids intruded between 2213 and 2060 Ma and overlap with the volcaniclastic units dated between 2211 and 2064 Ma. The simultaneous occurrence of the magmatic events and irregular distribution of the rock ages hamper the formulation of a stratigraphic succession. SHRIMP spot analyses were done on older cores, crystals and rims from 23 rocks from the Bolé-Wa region in west-central Ghana. The crystallization ages range from 2195 to 2118 Ma, the inherited ages from 2876 to 2130 Ma, and metamorphic ages from 2114 to 2090 Ma. Aided by metamorphic, structural and chemical studies an older geotectonic cycle (2195–2150 Ma), containing the Dole and Guropie Suite and Bolé Group, was established. These units were subjected to several orthogonal and shear deformation events. These events were followed by the contemporaneous Sawla calc-alkaline monzonitic plutonism (2132–2126 Ma) and deposition of the epiclastic Maluwe Group (2137–2125 Ma) of calc-alkaline felsic to tholeiitic volcanic origin. Deformation of the basin beds was succeeded by the intrusion of the Tanina Suite granitoids of 2122–2120 Ma, which, themselves, were deformed prior to 2119 Ma. At 2118 Ma syenite and gabbro intruded along conjugate extension fractures. The gabbro and syenite of the Wakawaka Suite were only affected by three events of brittle strike-slip faulting. The first had significant displacement along NNE- to NE-directed shear zones, while the latter only formed conjugate joint systems with limited transport. Palaeo- to Neoarchaean cores, the oldest yet reported in the Baoulé Mossi domain, are restricted to the gneissic Dole Suite biotite granites. The presence of Dole-, Guropie-, Sawla-, and Tanina-aged older cores and grains in younger rocks reflects continuous reworking of the developing crust during successive magmatic episodes. Zircon rim growth between 2105 and 2090 Ma indicates posttectonic crustal thickening. The low Rb/Sr R_o of ～0.7032 of gabbro and monzonite, and the recycling of the Birim-age crust confirm the primary and juvenile nature of the West African craton after ～2195 Ma. With the various ages obtained, it was possible to link deposition, magmatism and deformation to crustal processes, and establish the cyclic geotectonic evolution in the West Africa craton (individual basin opening and closure) over time as part of an intraoceanic arc–back-arc basin system.     

Study of the Stability of Aluminophosphate Glasses–Matrices for Immobilization of Radioactive Waste

Doklady Earth Sciences - Liquid radioactive wastes of the reprocessing of spent nuclear fuel are included in a glassy Na–Al–P matrix for subsequent placement in underground storage....     

Estimation of the Buffer Properties of Natural Waters with Account for the Acid–Base Characteristics of Humic Substances

The influence of the acid–base properties of humic substances in natural waters on the buffer capacity value is considered. An alternative way of calculation of the ANC parameter taking into account the dual nature of the humus organic of waters is proposed. Zonal aspects of the distribution of natural waters over ANC values are evaluated, and the features affecting these parameters are singled out.