Paleomagnetic age and palaeobiological significance of hominoid fossil strata of Yuanmou Basin in Yunnan

The Yuanmou area in Yunnan Province is a fa-mous place for origin of mankind. Qian Fang et al. found tooth fossils of Yuanmou man in Shangnabang Village of Yuanmou in 1965. Jiang Nengren et al. identified the hominoid teeth from animal fossils un-earthed near Zhupeng Village in the Xiaohe Basin which were delivered by the local peasants. Hominoid fossils were also found in Leilao Village of Yuanmou afterward. These great discoveries have aroused ex-tensive concern in academic circle[1,2…     

Chemical studies of L chondrites. VI: variations with petrographic type and shock-loading among equilibrated falls

To study compositional trends associated with open and closed system metamorphism and/or shock-induced heating of the L4-6 chondrite parent(s), we used ICPMS and RNAA to quantify 51 trace elements in 48 chemically representative fall samples. With these data, we used graphic and two multivariate statistical methods for examining evidence for compositional differences with respect to petrographic type and degree of shock loading. Comparisons of mildly shocked (S1-S3) L5 and L6 suites (9 and 8 chondrites, respectively) yield no convincing statistical evidence for a difference in trace element content. Our multivariate comparisons show a difference on a model-dependent basis, but yield indeterminate results on a model-independent basis. Compositionally, suites of strongly shocked (S4-S6) and mildly shocked L4-6 chondrites (26 and 19 samples, respectively) can be distinguished at statistically significant levels on both model-dependent and -independent bases. In the strongly shocked suite, contents of refractory lithophiles are higher, and siderophiles and volatiles are lower than those of the mildly shocked suite at moderately (p ≤ 0.05) to highly significant (p ≤ 0.01) levels. Our studies suggest that chemical differences from vaporization and loss of volatiles along with metal/silicate partitioning are present from extended cooling of shock-heated bodies produced by intermittent impacts, especially the massive impact(s) that disrupted the L chondrite parent(s) ∼500 Ma ago.     

Gene Expression Analysis for Exposure to Estrogenic Substances

Zebrafish (Danio rerio) were exposed with 17β‐estradiol (E2) and nonylphenol (NP) in different concentrations. Gene expression analysis was carried out by two different approaches. First, RT‐PCR experiments were performed for the examination of expression levels of the two marker genes vitellogenin and aromatase. This approach showed a significant increase in the expression of the vitellogenin gene in exposed male fish (500 ng/L 17β‐estradiol and 250 μg/L nonylphenol). This egg yolk protein is usually not synthesized in male vertebrates. A slight decrease of expression of the aromatase gene was observed in exposed female zebrafish. Aromatase is known to catalyze the conversion of androgens to estrogens. Second, DNA microarray experiments were carried out, which allow the simultaneous examination of the expression levels of a great number of marker genes. The microarray experiments resulted in an up‐regulation of vitellogenin up to 850‐fold. In addition, several other genes were identified to be up‐regulated by estrogens, for example the high mobility group box protein ssrp1 (78‐fold) or the chaperonin containing t‐complex polypeptide 1, beta subunit cctb (22‐fold).     

Formation of Al-rich titanite (CaTiSiO4O–CaAlSiO4OH) reaction rims on ilmenite in metamorphic rocks as a function of fH2O and fO2

Reaction rims of titanite on ilmenite are described in samples from four terranes of amphibolite-facies metapelites and amphibolites namely the Tamil Nadu area, southern India; the Val Strona area of the Ivrea-Verbano Zone, northern Italy, the Bamble Sector, southern Norway, and the northwestern Austroalpine Ötztal Complex. The titanite rims, and hence the stability of titanite (CaTiSiO₄O) and Al–OH titanite, i.e. vuaganatite (hypothetical end-member CaAlSiO₄OH), are discussed in the light of fH₂O- and fO₂-buffered equilibria involving clinopyroxene, amphibole, biotite, ilmenite, magnetite, and quartz in the systems CaO–FeO/Fe₂O₃–TiO₂–SiO₂–H₂O–O₂ (CFTSH) and CaO–FeO/Fe₂O₃–Al₂O₃–SiO₂–H₂O–O₂ (CFASH) present in each of the examples. Textural evidence suggests that titanite reaction rims on ilmenite in rocks from Tamil Nadu, Val Strona, and the Bamble Sector originated most likely due to hydration reactions such as clinopyroxene + ilmenite + quartz + H₂O = amphibole + titanite and oxidation reactions such as amphibole + ilmenite + O₂ = titanite + magnetite + quartz + H₂O during amphibolite-facies metamorphism, or, as in the case of the Ötztal Complex, during a subsequent greenschist-facies overprint. Overstepping of these reactions requires fH₂O and fO₂ to be high for titanite formation, which is also in accordance with equilibria involving Al–OH titanite. This study shows that, in addition to P, T, bulk–rock composition and composition of the coexisting fluid, fO₂ and fH₂O also play an important role in the formation of Al-bearing titanite during amphibolite- and greenschist-facies metamorphism.     

GEO-REFERENCING WITHOUT GROUND CONTROL

A geo-reference is a global or regional geographical or geodetic coor-dinate system to which sensors or spatial object data are related.Hence,geo-ref-erencing is close to the well known photogrammetric concept of exterior or abso-lute orientation,the common execution of which is indirect,via the use of groundcontrol point.GPS and INS technologies have changed the situation,permittingdirect measurement of position and attitude parameters and making exterior orien-tation feasible without ground control at all,in principle.The analysis of accuracyand reliability performance discloses,however,that especially INS does not yetmeet the high demands of photogrammetry.Moreover,control of systematic er-rors,the problem of datum transformation,and reliability conditions make theuse of some ground control points still mandatory,at least for any high perfor-mance geo-referencing.     

Subsolidus Phase Relations in the System MgO-SiO_2-Cr-O and Thermodynamic Properties of Related Cr~(2+)-Containing End-members

Subsolidus phase relations have been determined in the systems SiO2-Cr-O and MgO-SiO2-Cr-O in equilibrium with metallic Cr, at 1100 to 1500℃ and 0 to 2.88 GPa. The results show that there are no ternary phases in the SiO2-Cr-O system at these conditions, i.e., only the assemblage eskolaite-Cr-metal-quartz (or tridymite) is found. In the MgO-containing system, however, extensive substitution of Cr2+ for Mg is observed in (Mg, Cr2+)2SiO4 olivine, (Mg, Cr2+)2Si2O6 pyroxene, and (Mg, Cr2+)Cr2O4 spinel. Cr3+ levels in olivine and pyroxene are below detection limits. The pyroxene is orthohombic at XCrPx2+ < 0.2, monoclinic at higher XCrPx2+ . Thestructure of the spinels becomes tetragonally distorted at XCr2+Sp >0.2. The experimental datahave been fitted to a thermodynamic model, and the authors obtained the mixing parameter (W) of Mg-Cr2+ in olivine, pyroxene and spinel, and the relation between temperatures and free energies of formation for the end-members: Cr2+-olivine (Cr2SiO4), Cr2+-pyroxene (Cr2Si2O6)     

Lamellar nigerite in Zn-rich spinel from the Falun deposit,Sweden

Lamellar nigerite is found in Zn-rich spinel from a sample that contains chiefly anthophyllite + spinel + cordierite, lesser amounts of quartz and chlorite, as well as sphalerite, pyrite, pyrrhotite, and galena, and rare cassiterite and rutile. Nigerite can be described as interlayering of spinel-like (R²⁺Al₂O₄) and nolanite-like ((Sn, Ti)Al₄O₈) structures. In nigerite, the spinel-like part is also compositionally related to spinel, but in the nolanite-like part only the structural analogy exists. Stoichiometric assumptions that relate the anhydrous cation sum to the amount of R⁴⁺ cations present, allow Fe³⁺ estimates from microprobe analyses, and a representative analysis gives the following anhydrous formula: Mg_1.30Fe _0.65 ²⁺ Zn_3.03Mn_0.03Al_11.65Fe _0.35 ³⁺ Sn_0.32Ti_0.18O₂₄.The nigerite is Zn-rich with a Zn ratio (Zn/(Zn+Mg+ Fe²⁺)) of about 0.59, and the Sn ratio (Sn/(Sn+Ti)) that ranges from about 0.63 to 0.41. The Fe³⁺ content in these samples ranges from 0.35 to 0.52 (24 oxygen basis).Textures suggest that the nigerite could have formed by the breakdown of R ₂ ²⁺ (Sn, Ti)O₄ and R²⁺Al₂O₄ spinel components during more complex reactions. An experimental investigation of the MgAl₂O₄-Mg₂SnO₄ join indicates that the solubility of Mg₂SnO₄ component in spinel over the T interval 500 to 900° C is about 0.5 to 3.0 mole %. This, coupled with the increased solubility expected from the presence of Ti, gives good agreement with the 2.4 to 2.6 mole % R ₂ ²⁺ (Sn, Ti)O₄ component in spinel that is estimated to be the maximum necessary to form the compositions and amounts of observed nigerite.     

Riyadh and its development

After World War II Saudi Arabia has experienced spectacular changes. Based on huge oil and gas revenues a particularly rapid growth of population and a spectacular urbanization took place. One of the most booming cities in the desert environment of the arabian peninsula is the Kingdoms capital city of Riyadh. With a built-up area of 3.5 km² only before 1950 the city's present-day expansion reaches more than 500 km². During the same period of time the population of Riyadh grew from less than 50,000 in 1945 to more than 1.4 Mio. in 1985. Such an explosive development can be documented best by a satellite image. In this paper the process of urbanization of Riyadh is presented by the interpretation of a MOMS image taken in 1984, documenting the geographic situation, urban structures, and the city's development.