161 resultados para Xenarthra, Fossil


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We present a 47-year-long record of sea surface temperature (SST) derived from Sr/Ca and U/Ca analysis of a massive Porites coral which grew at ~4150 calendar years before present (B.P.) in Vanuatu (southwest tropical Pacific Ocean). Mean SST is similar in both the modern instrumental record and paleorecord, and both exhibit El Niño-Southern Oscillation (ENSO) frequency SST oscillations. However, several strong decadal-frequency cooling events and a marked modulation of the seasonal SST cycle, with power at both ENSO and decadal frequencies, are observed in the paleorecord, which are unprecedented in the modern record.

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In the green Oligocene clay of Krizanovice (former Krzyzanowicz) the author found numerous black nodules. In the 3-4 centimeter thick black crust of a particular specimen the concentration in MnO2 is evaluated at 46.6% MnO2. The determination was done using the Volhard's method (precipitation of Fe by ZnO and titration with KMnO4). Only the dissoleved part in HCL was analysed. The non soluble residue was essentially a silica precipitate in the form of many gray flakes. The specific gravity of the crust was evaluated at 3.8. In the internal yellow core the amount of manganese is about 2.39% MnO2. Due to the light color it is judged to probably be in the form of Mn2O3.