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93.
美国大西洋陆架35,000年来的海平面曲线,是建立在80多个放射性碳年代的基础上,其中15个年代是老于15,000年代的。测年的材料包括浅水软体动物、鲕状岩、珊瑚藻、海滩岩和盐沼泥炭。30,000—35,000年前的海平面,曾经是接近于现在的海平面的。随后冰川发育,16,000年前海平面降低到负130米左右。全新世海侵可能开始于约14,000年前,并迅速地延续到约7,000年前。世界大多数大陆架的年代和这条曲线相一致,说明这条曲线大致是这个时期海平面升降的曲线。 相似文献
94.
正In Espírito Santo State,Brazil,between the municipalities of Vitória,Colatina and Ecoporanga,there is a mountainous region characterized by a shear zone which trends NNW-SSE and is filled by a diabase dyke 相似文献
95.
L. BARATOUX M.W. JESSELL U. S?DERLUND R.E. ERNST M. BENOIT S. NABA C. COURNèDE S. PERROUTY V. METELKA D. YATTE D.P. DIALLO P.M. NDIAYE D. BARATOUX 《《地质学报》英文版》2016,90(Z1):29-29
正Over 20 sets of dolerite dykes crosscutting Paleoproterozoic basement in West Africa were distinguished via the interpretation of regional and high resolution magnetic airborne data of West African Craton 相似文献
96.
The composition of the saturated hydrocarbon fraction of soluble organic matter (bitumen) from the Krepoljin brown coal basin (East Serbia) of Miocene age was investigated. The Krepoljin basin is especially interesting from a geochemical point of view. Namely, by the end of Tertiary Period, the basin was covered by powerful Mesozoic formations of great possibilities, the bedding became hermetically enclosed and protected from subsequent external influences. The nature of early diagenetic processes in the environment with abundant accumulation of organic substance is defined by the molecular content of bitumen through the connections of molecular structures to potential precursors in paleoplant phylla, as well as by the degree of their diagenetic transformations. The hierarchy of parameters based on molecules of saturated hydrocarbons was determined by applying the principal component analysis to the soluble organic matter. The most significant, most “loadings” values of component C1, are the plant types such as precursors or participants in early diagenetic transformations of steranes Cs27-algal precursor material, Cs28-moulds, Cs29-higher land and water plants; resinous from the group of higher plant gymnosperms (G); also triterpanes α and β-amirin-dicotyledonous angiosperms (A) and bacterial and/or terrestrial plants population represented by hopanes/moretanes; as well as the parameters which describe the degree of diagenetic/maturation transformation of precursor biomass, and based on next reactions: (1) shifting of methyl group, influenced by the inorganic sediment constitutents, sterane-rearranged steranes, (2) isomerization in the ring system, ααα→βββ C29 sterane as well as (3) isomerization on chiral center of the side chain sequence R→S C29 sterane S/(S+R). Additionally, a pyrite-derived inhibitory effect on the rearrangment of C29 steranes must be taken into account, but not on triterpanes reaction. Non-appearance of statistically important correlations, before all with maturational depended parameters, and after all also with source indicators contributies to the affirmation of the newly-suggested parameter α-Phyllocladane/S27 as the real source biomarker of coal. Indicators derived from the distribution and abundance of n-alkanes and isoprenoid alkanes are of less significance in hierarchy of parameters. 相似文献
97.
Pavle Tan?i? Predrag Vuli? Reinhard Kaindl Bernhard Sartory Radovan Dimitrijevi? 《《地质学报》英文版》2012,86(2):394-405
The macroscopically-zoned grandite from the garnetite skarn of Meka Presedla (Kopaonik Mountain, Serbia) was studied with optical microscopy, electron microprobe analysis (EMPA), Fourier transform infra-red (FT–IR), and Raman methods. The EMPA results indicate that the main core–rim compositional variations (Ca2.93–2.97Mn0.05–0.06Mg0.00–0.01Al1.14–1.26Fe3+0.72–0.83Ti0.00–0.02Si2.97–3.02O12) slightly differ along the zones, showing evidence for a quasi-cyclic alternation of the oscillatory zoning nature. Among this, considerable variation is observed only by the Al–Fe3+ substitutions in the octahedral site. The EMPA also indicate that the grandite zones compositionally vary, mostly within ±1 and ±2 mol% of the homogeneity level range, that is, Grs64±1Adr36±1Sps2 (A), Grs62±1Adr38±1Sps2 (B), Grs59±2Adr40±2Sps2 (C), Grs58±2Adr41±2Sps2 (D), and Grs58±1Adr41±1Sps2 (E). Therefore, the investigated garnet can be considered as relatively highly homogeneous. The majority of compositions lie within the narrow miscibility region of 0.58±2相似文献
98.
<正>Representatives of the extinct psocid family Empheriidae are known from Eocene Baltic amber, Lowermost Eocene French amber(Oise),and Lower Cretaceous Spanish amber(Alava).We report herein the first discovery of an empheriid psocid from the Cretaceous amber of New Jersey as Jerseyempheria grimaldii gen.et sp. nov.The fossil is figured and described.The new species is distinguished from related taxa.A discussion and checklist of Empheriidae are provided. 相似文献
99.
<正>A new genus and species of Rhachiberothidae,Raptorapax terribilissima gen.et sp.nov.from the Cretaceous amber of Lebanon is described.The new genus is assigned to the subfamily Paraberothinae.The new material confirms the great diversity of the group in the Cretaceous age and its decrease in diversity in recent times. 相似文献
100.
Cearadactylus atrox is one of the first pterosaurs unearthed from the Araripe Basin (Northeast Brazil) (Leonardi and Borgomanero 1983, 1985) (Fig.1). The fossil was preserved in a calcareous concretion typical of the Romualdo Formation and comprised an almost complete skull with lower jaw, but lacked the occipital region. 相似文献