Investigating the Sedimentary Structure of the Baza Basin (Southern Spain) using Seismic Reflection Profiling

The Baza Basin is an intra-mountain evaporitic basin in Southern Spain. It is the largest of the Late Neogene continental basins of the Betic Cordillera. During the last 7 million years the basin alternately was flooded and fell dry. Therefore, up to 2.5 km thick lacustrine and ancillary continental deposits are found which provide an unique archive of climatic changes and paleo-climatic events. Plans exist to analyze the sedimentary record with regard to the paleo-climate in the Mediterranean as well as on a global scale within a scientific drilling project. In preparation for the future drilling activities, controlled-source seismic measurements are used to investigate the structure of the Baza Basin and to find local zones of neo-tectonic deformation bounding the basin to the west (Baza fault). In October 2013 a seismic reflection experiment was carried out in the center of the Baza Basin. A net of three 2D seismic profiles was arranged crossing the basin and the bounding fault system. A vibroseis source (two vibrators with 200 kN peak force each) was used with a source point distance of 60 m along each of the 18 km long profiles. Eight sweeps with a frequency range of 8 ­- 100 Hz were conducted at each source point. The seismic wavefield was recorded by a cable-free acquisition system of more than 330 continuously operating digital data recorders. The receivers were spread along the currently active profile with a spacing of 20 m. They were moved in a roll-along-configuration to mainly cover the near-field offsets of the source points. The seismic data of the three profiles were conventionally processed so far. Tomographic inversion of the first arrivals (P-waves) provide additional information. The images show the asymmetrical basin geometry. Several seismic sequences and the basement can be identified. Furthermore, the Baza fault system and a series of other - previously unknown - faults can be seePeer Reviewe

Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362

Isotopengeochemische und mineralogische Untersuchungen an postvariscischen hydrothemalen Silikaten

SIGLECopy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Sources, degassing, and contamination of CO₂, H₂O, He, Ne and Ar in basaltic glasses from Kolbeinsey Ridge, North Atlantic

New volatile data (CO₂, H₂O, He, Ne, and Ar) are presented for 24 submarine basaltic glasses from the Kolbeinsey Ridge, Tjörnes Fracture Zone and Mohns Ridge, North Atlantic. Low CO₂ and He contents indicate that magmas were strongly outgassed with the extent of degassing increasing toward the south, as expected from shallower ridge depths. Ne and Ar are significantly more abundant in the southernmost glasses than predicted for degassed melt. The strong atmospheric isotopic signal associated with this excess Ne and Ar suggests syn- or posteruptive contamination by air. Degassing, by itself, cannot generate the large variations in δ13C values of dissolved CO₂ or coupled CO₂-Ar variations. This suggests that δ13C values were also affected by some other processes, most probably melt-crust interaction. Modelling indicates that degassing had a negligible influence on water owing to its higher solubility in basaltic melt than the other volatiles. Low H₂O contents in the glasses reflect melting of a mantle source that is not water-rich relative to the source of N-MORB. Before eruption, Kolbeinsey Ridge melts contained ~400 ppm CO₂ with δ13C of -6‰, 0.1 to 0.35 wt.% H₂O, 3He/4He ~ 11 RA, and CO₂/3He of ~2 x 10⁹. We model restored volatile characteristics and find homogeneous compositions in the source of Kolbeinsey Ridge magmas. Relative to the MORB-source, He and Ne are mildly fractionated while the 40Ar/36Ar may be low. The 3He/4He ratios in Tjörnes Fracture Zone glasses are slightly higher (13.6 RA) than on Kolbeinsey Ridge, suggesting a greater contribution of Icelandic mantle from the south, but the lack of 3He/4He variation along the Kolbeinsey Ridge is inconsistent with active dispersal of Icelandic mantle beyond the Tjörnes Fracture Zone

Sr-Nd-Pb isotope evidence against plume-asthenosphere mixing north of Iceland

Iceland straddles the mid-Atlantic spreading axis, between the Kolbeinsey Ridge to the north and the Reykjanes Ridge to the south. Published geochemical data from the Reykjanes Ridge show evidence for mixing between a MORB component and the Iceland plume. Available data from the Kolbeinsey Ridge suggest that similar mixing may not be occurring there. To investigate in detail the relationship between the Iceland plume and MORB along the Kolbeinsey Ridge, we have collected and analysed samples between the Tjo¨rnes and Spar fracture zones (ca. 67°–69°N). The 16 Kolbeinsey Ridge samples show limited isotopic variation and are characterised by relatively unradiogenic Pb (206Pb/204Pb= 17.912 to 18.053, 207Pb/204Pb= 15.404 to 15.453 and 208Pb/204Pb= 37.543 to 37.690, 87Sr/86Sr= 0.70280 to 0.70298, 143Nd/144Nd= 0.51307 to 0.51323). On the basis of their Rb, Sr, Nd, Sm, U, Th and Pb concentrations, the basalts are N-type MORB. Sr and Nd isotope ratios show significant systematic variations with latitude, becoming more enriched (87Sr/86Sr increases, 143Nd/144Nd decreases) towards Iceland, apparently supporting the classical model of plume-asthenosphere mixing. However, the Pb isotopes show no such relationship, and are thus inconsistent with this mixing model. On the basis of Pb and Sr isotope data it is possible to exclude the Iceland source as an end-member in the genesis of the Kolbeinsey Ridge basalts, implying that Iceland plume material does not flow northward along the Kolbeinsey Ridge. The isotopic variations within the Kolbeinsey data set can be attributed to heterogeneities in the MORB source. The boundary between the plume and MORB sources appears to coincide with the Tjo¨rnes Fracture Zone. This fracture zone may, by analogy with the Australia-Antarctic Discordance, overlie a zone of mantle convergence. The topographic anomalies over the Kolbeinsey and Reykjanes Ridges imply that hot, less dense material underlies them both. The absence of an Icelandic plume signature in the Kolbeinsey geochemistry, however, leads us to propose an asymmetrical shape for the plume, generated by a southerly component of flow in the Kolbeinsey MORB source. A similar flow direction has previously been proposed for the whole North Atlantic on the basis of independent mantle mass-balance calculation

Architecture and tectono-stratigraphic evolution of the intramontane Baza Basin (Bétics, SE-Spain): Constraints from seismic imaging

The Baza basin is a large Neogene intramontane basin in the Bétic Cordillera of southern Spain that formed during the Tortonian (late Miocene). The Bétic Cordillera was produced by NW–SE oblique convergence between the Eurasian and African Plates. Three seismic reflection lines (each 18 km long; vibroseis method) were acquired across the Baza basin to reveal the architecture of the sedimentary infill and faulting during basin formation. We applied rather conventional CDP data processing followed by first arrival P-wave tomography to provide complementary structural information and establish velocity models for the post-stack migration. These images show a highly asymmetric structure for the Basin with sediments thickening westward, reaching a maximum observed thickness of > 2200 m near the governing Baza Fault zone (BFZ). Three major seismic units (including several subunits) on top of the acoustic basement could be identified. We use stratigraphic information from the uplifted block of the BFZ and other outcrops at the basin edges together with available information from neighboring Bétic basins to tentatively correlate the seismic units to the known stratigraphy in the area. Until new drilling or surface outcrop data is not available, this interpretation is preliminary. The seismic units could be associated to Tortonian marine deposits, and latest Miocene to Pleistocene continental fluvio-lacustrine sediments. Individual strands of the BFZ truncate the basin sediments. Strong fault reflections imaged in two lines are the product of the large impedance contrast between sedimentary fill and basement. In the central part of the Basin several basement faults document strong deformation related to the early stages of basin formation. Some of these faults can be traced up to the shallowest imaged depth levels indicating activity until recent times. © 2017 Elsevier B.V.The project was funded by the German Science Foundation (grant HA3326/2-1) and the GFZ Potsdam. Recording equipment was provided by the Geophysical Instrument Pool (GIPP) of the GFZ (grant GIPP201312). We thank the contractor companies Geofisyka Torun (Poland; vibroseis sources) and GEOLAND (Spain; permitting) for the professional work rendered to the project. Field acquisition was performed by mixed teams from Germany, Spain, Italy, and the U.S.A., and we thank all field crews for their excellent work. Teresa Teixido (Granada) kindly supported the field work. Seismic interpretation was performed at ICTJA-CSIC using Petrel software (Schlumberger). CGL2010-21568 - Spanish Government project supported MJ Jurado research, and the Ramon y Cajal program supported L Gibert.Peer reviewe

238U and 230Th Excesses in Kolbeinsey Ridge Basalts

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