55 resultados para Readability Formulas


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The Palynology of two sections recovered during Leg 93 drilling by the Deep Sea Drilling Project in the continental rise along the western margin of the North Atlantic is reported. In Hole 603B at Site 603, the dinoflagellate stratigraphy indicates that the interval from Cores 603B-82 to 603B-26 ranges in age from late Berriasian to Santonian. The BlakeBahama Formation ranges from late Berriasian to Aptian. The Hatteras Formation ranges from Aptian to Cenomanian, although the uppermost part may be Turonian. Dinoflagellate evidence from the middle part of the Plantagenet Formation indicates an age from late Coniacian or early Santonian to Santonian within the interval of Cores 603B-28 to 603B-26. Magnetic polarity evidence of the stratigraphy of the Early Cretaceous for the western North Atlantic indicates a reliable correlation with the dinoflagellate zonation. The stratigraphic sequence of palynologically defined organic facies in carbonaceous claystone lithologies in Hole 603B shows that organic stratigraphic units consisting predominantly of fecal-pellet-derived, pelagic organic matter (xenomorphic facies) alternate with units consisting predominantly of terrigenous organic matter (tracheal and exinitic facies), corresponding to that described from other sites in the North Atlantic. A terrigenous organic facies is identified for the first time from the Plantagenet Formation. The claystone organic facies and major lithofacies are closely correlated. The tracheal and exinitic facies occur in carbonaceous terrigenous claystones and claystone turbidites associated with sandstone/siltstone terrigenous turbidites. The xenomorphic facies occurs in claystones within pelagic limestones lacking any turbidites, and in blackish, noncalcareous claystones which correlate in age with the marine-carbon-rich sapropels which are widespread in the North Atlantic Cenomanian. This facies also occurs with an admixture of terrigenous organic particles in the Blake-Bahama Formation, but the mixture is consistent with the submarine fan setting of this interval. The concentration of refractory organic matter (carbonized particles) in the micrinitic and carbonized tracheal facies is considered to be the result, at least in part, of the oxidation of sediment buried below a surface slowly accumulating pelagic clays below the carbonate compensation depth. The progressive increase in number of dinoflagellate species per stage through the Early Cretaceous (except for the late Barremian-Aptian) may have resulted indirectly from the generally progressive rise in global sea level during this time. At Site 605, the dinoflagellate stratigraphy across the Cretaceous/Tertiary boundary is remarkably close to that published from the Maestrichtian and Danian of Denmark. The Maestrichtian/Danian boundary is placed precisely within Section 605-66-1 by dinoflagellate evidence, agreeing with that predicted by other microfossils. The new dinoflagellate-cyst-based genus, Pierceites and its new species P. schizocystis, and the new combination P. ( = Trithyrodinium) pentagonum (May) are proposed. Diacanthum hollisteri Habib, type species of Diacanthum, is emended to accommodat e cysts with the archeopyle formulas P3'', 2P2''-3'', 2P3''-4'', and 3P2''-3''-4''.

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This dataset present result from the DFG- funded Arctic-Turbulence-Experiment (ARCTEX-2006) performed by the University of Bayreuth on the island of Svalbard, Norway, during the winter/spring transition 2006. From May 5 to May 19, 2006 turbulent flux and meteorological measurements were performed on the monitoring field near Ny-Ålesund, at 78°55'24'' N, 11°55'15'' E Kongsfjord, Svalbard (Spitsbergen), Norway. The ARCTEX-2006 campaign site was located about 200 m southeast of the settlement on flat snow covered tundra, 11 m to 14 m above sea level. The permanent sites used for this study consisted of the 10 m meteorological tower of the Alfred Wegener Institute for Polar- and Marine Research (AWI), the international standardized radiation measurement site of the Baseline Surface Radiation Network (BSRN), the radiosonde launch site and the AWI tethered balloon launch sites. The temporary sites - set up by the University of Bayreuth - were a 6 m meteorological gradient tower, an eddy-flux measurement complex (EF), and a laser-scintillometer section (SLS). A quality assessment and data correction was applied to detect and eliminate specific measurement errors common at a high arctic landscape. In addition, the quality checked sensible heat flux measurements are compared with bulk aerodynamic formulas that are widely used in atmosphere-ocean/land-ice models for polar regions as described in Ebert and Curry (1993, doi:10.1029/93JC00656) and Launiainen and Cheng (1995). These parameterization approaches easily allow estimation of the turbulent surface fluxes from routine meteorological measurements. The data show: - the role of the intermittency of the turbulent atmospheric fluctuation of momentum and scalars, - the existence of a disturbed vertical temperature profile (sharp inversion layer) close to the surface, - the relevance of possible free convection events for the snow or ice melt in the Arctic spring at Svalbard, and - the relevance of meso-scale atmospheric circulation pattern and air-mass advection for the near-surface turbulent heat exchange in the Arctic spring at Svalbard. Recommendations and improvements regarding the interpretation of eddy-flux and laser-scintillometer data as well as the arrangement of the instrumentation under polar distinct exchange conditions and (extreme) weather situations could be derived.

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The upper part of the basaltic substratum of the Atlantic abyssal plain, approaching subduction beneath the Barbados Ridge and thus presumably beneath the Lesser Antilles island arc, is made of typical LREE-depleted oceanic tholeiites. Mineralogical (microprobe) and geochemical (X-ray fluorescence, neutron activation analyses) data are given for 12 samples from the bottom of Hole 543A, which is 3.5 km seaward of the deformation front of the Barbados Ridge complex. These basalts are overlain by a Quaternary to Maestrichtian-Campanian sedimentary sequence. Most of the basalts are relatively fresh (in spite of the alteration of olivine and development of some celadonite, clays, and chlorite in their groundmass), and their mineralogical and geochemical compositions are similar to those of LREE-depleted recent basalts from the Mid-Atlantic Ridge. The most altered samples occur at the top of the basaltic sequence, and show trends of enrichment in alkali metals typical of altered oceanic tholeiites.

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Duplicate, filtered samples of North Atlantic Deep Water (NADW) were irradiated for 28 days in a solar simulator. Duplicate dark controls were placed alongside the irradiated samples. After 28 days, samples were extensively photo-degraded based upon colored dissolved organic matter (CDOM) photo-bleaching (> 95%). Samples were solid phase extracted using PPL resin to isolate, concentrate and desalt the dissolved organic matter (DOM) in the samples. Ultrahigh resolution electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) enabled 3024 molecular formulas to be identified in the dark control. Photo-degradation decreased molecular diversity, with 2402 formulas assigned post-irradiation. Molecular formulas were classified based upon their photo-lability as 1) photo-resistant; 2) photo-labile; and, 3) photo-produced. Photo-resistant DOM made up 73% of all formulas and was dominated by highly unsaturated molecular signatures consistent with carboxylic-rich alicyclic molecules, suggesting that these apparently bio-refractory compounds may also survive multiple passages through sunlit surface waters and thus accumulate for timeframes exceeding ocean ventilation. Photo-labile DOM was enriched in low molecular weight formulas, aromatic molecular formulas, and sulfur and phosphorous containing formulas. Compounds containing both sulfur and nitrogen were particularly photo-labile and may represent an underappreciated component of the photo-reactive CDOM pool. Photo-produced DOM was enriched in higher molecular weight formulas, as well as aliphatic and peptide formulas. Molecular formulas are indexed by their photo-lability classification in the supplementary information.

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Gabbroic rocks and their late differentiates recovered at Site 735 represent 500 m of oceanic layer 3. The original cooling of a mid-ocean ridge magma chamber, its penetration by ductile shear zones and late intrusives, and the subsequent penetration of seawater through a network of cracks and into highly permeable magmatic hydrofracture horizons are recorded in the metamorphic stratigraphy of the core. Ductile shear zones are characterized by extensive dynamic recrystallization of primary phases, beginning in the granulite facies and continuing into the lower amphibolite facies. Increasing availability of seawater during dynamic recrystallization is reflected in depletions in 18O, increasing abundance of amphibole of variable composition and metamorphic plagioclase of intermediate composition, and more complete coronitic or pseudomorphous static replacement of magmatic minerals. Downcore correlation of synkinematic assemblages, bulk-rock oxygen isotopic compositions, and vein abundance suggest that seawater is introduced into the crust by way of small cracks and veins that mark the end of the ductile phase of deformation. This "deformation-enhanced" metamorphism dominates the upper 180 and the lower 100 m of the core. In the lower 300 m of the core, mineral assemblages of greenschist and zeolite facies are abundant within or adjacent to brecciated zones. Leucocratic veins found in these zones and adjacent host rock contain diopside, sodic plagioclase, epidote, chlorite, analcime, thomsonite, natrolite, albite, quartz, actinolite, sphene, brookite, and sulfides. The presence of zircon, Cl-apatite, sodic plagioclase, sulfides, and diopside in leucocratic veins having local magmatic textures suggests that some of the veins originated from late magmas or from hydrothermal fluids exsolved from such magmas that were subsequently replaced by (seawater-derived) hydrothermal assemblages. The frequent association of these late magmatic intrusive rocks within the brecciated zones suggests that they are both artifacts of magmatic hydrofracture. Such catastrophic fracture and hydrothermal circulation could produce episodic venting of hydrothermal fluids as well as the incorporation of a magmatically derived hydrothermal component. The enhanced permeability of the brecciated zones produced lower temperature assemblages because of larger volumes of seawater that penetrated the crust. The last fractures were sealed either by these hydrothermal minerals or by late carbonate-smectite veins, resulting in the observed low permeability of the core.

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The JGOFS International Collection Volume 2: Integrated Data Sets CD is a coherent, organised compilation of existing data sets produced by member countries which participated in JGOFS. In most cases, the data were gathered from the JGOFS International Collection, Volume 1: Discrete Datasets DVD. To produce Vol. 1 data were taken from the original sources and copied "as is" on the DVD. For Vol. 2 data and metadata have been harmonized using the conversion software PanTool and the import routine of PANGAEA checking for completeness of metadata and defining the relations between data and metadata. Prior to the import, data had performed a technical quality control, i.e. format and readability of the file, availability and combination of parameters and units, range of values.