Pyrolysis-high resolution gas chromatography and pyrolysis gas chromatography-mass spectrometry of kerogens and kerogen precursors     

Dik van de Meent  Stephen C. Brown  R.Paul Philp  Bernd R.T. Simoneit 《Geochimica et cosmochimica acta》1980,44(7):999-1013

A series of kerogens and kerogen precursors isolated from DSDP samples, oil shales and Recent algal mats have been examined by Curie point pyrolysis-high resolution gas chromatography and gas chromatography-mass spectrometry. This study has shown that the three main types of kerogens (marine, terrestrial and mixtures of both) can be characterized using these techniques. The marine (algal) kerogens yield principally aliphatic products and the terrestrial kerogens yield more aromatic and phenolic products with some n-alkanes and n-alkenes. The yields of n-alkanes and n-alkenes increase and phenols decrease with increasing geologic age, however, pyrolysis-GC cannot be used to characterize the influence of short term diagenesis on the kerogen structure.  相似文献   

Determination of vertical temperature profiles for the atmospheric boundary layer by ground-based microwave radiometry     

Bernd Schönwald 《Boundary-Layer Meteorology》1978,15(4):453-464

A useful method for remote sensing of vertical temperature profiles in the atmospheric boundary layer is described. From angular measurements of brightness temperature at 58 GHz, profiles have been inferred up to an altitude of 700 m. Calculations were done with an iterative inversion procedure (Smith et al., 1972) using Twomey-type smoothing (Twomey, 1963). It is shown how an initial-guess profile can be directly derived from the radiation measurements using, a nomogram.  相似文献   

Diterpenoid compounds and other lipids in deep-sea sediments and their geochemical significance     

Bernd R.T Simoneit 《Geochimica et cosmochimica acta》1977,41(4):463-476

Cyclic diterpenoid compounds have been found by various investigators in the geosphere (e.g. fossil resins, coals, soil, shale and deep-sea sediments). These compounds occur in significant amounts only in higher plants and are therefore potential markers of terrigenous plant lipids.Diterpenoids with the abietane skeleton (mainly dehydroabietic acid) have been identified in the lipids of sediment samples from the northeast Pacific Ocean, Black Sea and North Atlantic Ocean. The presence of these resin-derived compounds correlated with the terrigenous clay components and with the presence of pollen. The presence of polycyclic diterpenoids was also correlated with the distribution patterns and inferred sources of other sediment lipid constituents (e.g. n-alkanes, n-fatty acids, etc.).Potamic transport, followed by turbidite redistribution are the probable input mechanisms of these resin-derived compounds to the deep-sea sediments. These diterpenoids appear to be excellent biological markers of resinous higher plants.  相似文献   

Using archaeological data and sediment parameters to review the formation of the Gravettian layers at Krems-Wachtberg     

Marc Händel  Roswitha Thomas  Tobias Sprafke  Philipp Schulte  Michael Brandl  Ulrich Simon  Thomas Einwögerer 《第四纪科学杂志》2021,36(8):1397-1413

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Sedimentary evidence of deglacial megafloods in the northern Gulf of Mexico (Pigmy Basin)     

Jean Carlos Montero-Serrano  Viviane Bout-Roumazeilles  Nicolas Tribovillard  Thomas Sionneau  Armelle Riboulleau  Aloys Bory  Benjamin Flower 《Quaternary Science Reviews》2009,28(27-28):3333-3347

Cored sediments from the Pigmy Basin, northern Gulf of Mexico, were analyzed in order to better constrain late deglacial and early Holocene paleoenvironmental and sedimentary changes in response to North American climate evolution. Mineralogical and geochemical proxies indicate the succession of two sedimentary regimes: dominantly detrital during the deglaciation (15–12.9 cal ka BP) whereas biogenic contribution relatively increased later on during the Younger Dryas and early Holocene (12.9 and 10 cal ka BP). Geochemical data reveal that the deglacial record mainly reflects variations of terrigenous supply via the Mississippi River rather than modifications of redox conditions in the basin. Specific variations of almost all the parameters measured in this paper are synchronous with the main deglacial meltwater episode (Meltwater Spike) described or modeled in previous marine or continental studies. During this episode, most parameters display “stair-step-like” – pattern variations highlighting three successive steps within the main meltwater flow. Variations in grain-size and clay mineral assemblage recorded in the Pigmy Basin indicate that the erosional regime was very strong on land during the first part of the Meltwater Spike, and then milder, inducing more subtle modifications in the sedimentary regime in this part of the Gulf. Specific geochemical and mineralogical signatures (notably, clay minerals and trace metal geochemistry) pinpoint a dominant origin from NW North America for detrital particles reflecting meltwater outflow from the south-western Laurentide Ice Sheet (LIS) margin during the most intense freshwater discharge. The observed decrease of the sedimentation rate from about 200 to 25 cm/ka at ca 12.9 ka evidenced a drastic decrease of erosional processes during late phase of discharge, consistently with the hypotheses of major reduction of meltwater flow. The major modification at 12.9 cal ka BP is interpreted to result from both modifications of the main Mississippi fluvial regime due to eastward and northward rerouting of meltwater flow at the onset of the Younger Dryas, and the increase of sea-surface temperature linked to insolation. Finally, slight grain-size modifications suggest that some freshwater discharges may have episodically reached the Gulf of Mexico after the Younger Dryas reflecting possible small adjustments of the postglacial hydrological regime.  相似文献   

Geochemistry of igneous rocks associated with ultramafic–mafic-hosted Cu (Co, Ni, Au) VMS deposits from the Main Uralian Fault (Southern Urals, Russia)     

Paolo Nimis  Paolo Omenetto  Bernd Buschmann  Peter Jonas  Vladimir A. Simonov 《Mineralogy and Petrology》2010,100(3-4):201-214

Ultramafic–mafic- and ultramafic-hosted Cu (Co, Ni, Au) volcanogenic massive sulfide (VMS) deposits from ophiolite complexes of the Main Uralian Fault, Southern Urals, are associated with island arc-type igneous rocks. Trace element analyses show that these rocks are geochemically analogous to Early Devonian boninitic and island arc tholeiitic rocks found at the base of the adjacent Magnitogorsk volcanic arc system, while they are distinguished both from earlier, pre-subduction volcanic rocks and from later volcanic products that were erupted in progressively more internal arc settings. The correlation between the sulfide host-rocks and the earliest volcanic units of the Magnitogorsk arc suggests a connection between VMS formation and infant subduction-driven intraoceanic magmatism.  相似文献   

Structural characteristics of the halite fabric type ‘Kristallbrocken’ from the Zechstein Basin with regard to its development     

Yvonne Küster  Bernd Leiss  Michael Schramm 《International Journal of Earth Sciences》2010,99(3):505-526

The Kristallbrocken are a characteristic centimetre- to decimetre-sized, laminated halite fabric type occurring in the Stassfurt Formation in the Zechstein Basin. Up to now, the nature of the Kristallbrocken, i.e. if they are relics of fine-grained, polycrystalline halite beds or clasts of ‘single crystal-layers’, as well as the deformation mechanisms of this halite type, were not clear from the literature. Drill core material from the salt deposit Teutschenthal at the southern rim of the Zechstein Basin now allowed investigating less intensely deformed samples for the first time. The deformational behaviour of these Kristallbrocken ranges from brittle to ductile, which is evidenced by fractured Kristallbrocken on the one hand and weakly bent or even folded Kristallbrocken on the other hand. Local X-ray texture measurements demonstrated that the Kristallbrocken are definitely single crystals and that they can be regarded as relics of formerly larger ‘single crystal-layers’ of up to several dm² in size. The folded Kristallbrocken clearly display by their single grain texture characteristics that their crystal lattice is bent, which was most likely enabled by a kind of flexural-shear folding, and did not develop after deformation from a fine-grained aggregate by recrystallisation. Due to their monocrystallinity, their originally large size, and the solid inclusions forming the internal lamination, the Kristallbrocken have clearly stronger rheological properties than the surrounding fine- to coarse-grained polycrystalline rock salt, and thus also deform by fracturing.  相似文献   

Microtopography,water storage and flow patterns in a fine‐textured soil under agricultural use     

Christina Bogner  Mohammadreza Mirzaei  Stéphane Ruy  Bernd Huwe 《水文研究》2013,27(12):1797-1806

Agricultural use of soils implies tillage and often compaction and therefore influences processes on soil surface and affects infiltration of water into the subsoil. Although many studies on soil surface processes or flow patterns in soils exist, works relating both are rare in literature. We did two tracer experiments with Brilliant Blue FCF on a tilled and compacted plot and a non‐tilled one to investigate water storage on the soil surface during simulated rainfall and changes of soil microtopography, to analyse the associated flow patterns in the soil and to relate both to tillage and compaction. Our results show that storage was larger on the tilled and compacted plot than on the non‐tilled one. After tillage, transport processes above the plough pan were partly disconnected from those underneath because macropores were disrupted and buried by the tillage operation. However, preferential flow along cracks occurred on both plots and the macropores buried below the tillage pan still functioned as preferential flow paths. Therefore, we conclude that the studied soil is susceptible to deep vertical solute propagation at dry conditions when cracks are open, irrespective of tillage and compaction. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

A high-resolution Late Glacial to Holocene record of environmental change in the Mediterranean from Lake Ohrid (Macedonia/Albania)     

Jack H. Lacey  Alexander Francke  Melanie J. Leng  Christopher H. Vane  Bernd Wagner 《International Journal of Earth Sciences》2015,104(6):1623-1638

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Business start-up promotional aid in Hungary     

Bernd Schlegel 《GeoJournal》1994,32(4):373-379

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