Geology and Geophysics

Terrestrial gravity fluctuations produce so-called Newtonian noise (NN) which is expected to limit the low frequency sensitivity of existing gravitational-waves (GW) detectors LIGO and Virgo, when they will reach their full potential, and of next-generation detectors like the Einstein Telescope. In this paper, we present a detailed characterization of the seismic field at Virgo's West End Building as part of the development of a Newtonian noise cancellation system. The cancellation system will use optimally filtered data from a seismometer array to produce an estimate of the Newtonian-noise generated by the seismic field, and to subtract this estimate from the gravitational-wave channel of the detector. By using an array of 38 seismic sensors, we show that, despite the influence of the complexity of Virgo's infrastructure on the correlation across the array, Wiener filtering can still be very efficient in reconstructing the seismic field around the test-mass location. Taking into account the division of the building's foundations into separate concrete slabs, and the different properties of the seismic field across them, we conclude that the arrays to be used for the Newtoniannoise cancellation at Virgo will require a relatively large number of seismometers per test mass, i.e. significantly more than 10. Moreover, observed variations of the absolute noise residuals over time, related to the daily evolution of anthropogenic noise, suggest that the Wiener filter will need to be updated regularly, probably more often than every hour, to achieve stationarity of the background level after subtraction.

Figure 1: Artist impression of the Einstein Telescope gravitational wave observatory situated at a depth of 200-300 meters in the Euregio Meuse-Rhine landscape. The triangular topology with 10 kilometers long arms allows for the installation of multiple so-called laser interferometers. Each of which can detect ripples in the fabric of space-time-the unique signature of a gravitational wave-as minute relative movements of the mirrors hanging at the bottom of the red and white towers indicated in the illustration at the corners of the triangle.

The Raniganj Formation (late Permian) forms the uppermost economic coal-bearing unit of the Gondwana succession. The dominant facies interpreted from analysis of cores from the Raniganj formation are classified as Sandstone dominated facies, Sandstone-shale heterolith facies, Shale facies and Coal facies. The natural Gamma response of Raniganj Formation shows predominance of repetitive fining upwards cycles. Integration of core analysis and geophysical log data of the Raniganj formation indicates meandering fluvial environment. The lower part of Raniganj Formation is channel dominated which corresponds to thick amalgamated sand bodies while the upper part represent overbank shows predominance of channel avulsion indicating a gradual change in accommodation space. Five major fining upward depositional sequences, bounded by sub-aerial unconformities (sequence boundaries) have been dentified in Raniganj formation, based on changes in depositional style that are correlated regionally. Each sequence comprises of Low accommodation system tract (LAST) at base and high accommodation system tract (HAST) at top. LAST is characterized by vertically stacked, multistory amalgamated channel sandstone dominated facies, while floodplain dominated facies characterize HAST. The coal seams deposited in LAST are thicker and relatively more continuous than the frequent thin seams of HAST. Such facies distribution study would be helpful for the development strategy for CBM blocks based on production priority.

Chasma is a deep, elongated and steep sided depression on planetary surfaces. Several hypothesis have been proposed regarding the origin of chasma. In this study, we analysed morphological features in north and south of Ius chasma. Collapsed pits and branched valleys alongwith craters are prominent morphological features surrounding Ius Chasma, which forms the western part of the well known Valles Marineris chasma system on Martian surface. Analysis of images from the High Resolution Stereo Camera (HRSC) in ESA’s Mars Express (MEX) with a spatial resolution of 10 m shows linear arrangement of pits north of the Ius chasma. These pits were initially developed along existing narrow linear valleys parallel to Valles Merineris and are conical in shape unlike flat floored impact craters found adjacent to them. The width of conical pits ranges 1–10 km and depth ranges 1–2 km. With more subsidence, size of individual pits increased gradually and finally coalesced together to create a large ...

Rapid climatic shifts across the last glacial to Holocene transition are pervasive feature of the North Atlantic as well as low latitude proxy archives. Our decadal to centennial scale record of summer monsoon proxy Globigerina bulloidesfrom rapidly accumulating sediments from Hole 723A, Arabian Sea shows two distinct intervals of weak summer monsoon wind coinciding with cold periods within A˚llerød inerstadial of the North Atlantic named here as IACP-A1 and IACP-A2 and dated (within dating uncertainties) at 13.5 and 13.3 calibrated kilo years before the present (cal kyr BP), respectively. Spectral analysis of the
Globigerina bulloidestime series for the segment 13.6–13.1 kyr (A˚llerød period) reveals a strong solar 208-year cycle also known as de Vries or Suess cycle, suggesting that the centennial scale variability in Indian summer monsoon winds during the A˚llerød inerstadial was driven by changes in the solar irradiance
through stratospheric-tropospheric interactions.

To understand the ecological preference, and timing and cause(s) of disappearance of S. lepidula, we analysed Neogene record of this taxon from Ocean Drilling Programme and Deep Sea Drilling Project sites located at bathyal to abyssal depths in the Atlantic and Indian oceans. Population plots of this species at various sites reveal that this taxon showed a substantial increase during the warm late Oligocene to the middle Miocene and suffered a major decline across the middle Miocene cooling event (15-13 Myr). S. lepidula disappeared at ~0.6 Myr very close to the MPT (0.9-0.8 Myr) from the Indian and Atlantic oceans, coinciding with a change from a 40 to 100 Kyr world with amplified ice-age cycles. We suggest that high-amplitude glacial cycles, frigid deep-water temperatures and strong circulation drove S. lepidula to nearly disappear across the MPT.

Oxygen and carbon isotope ratios in planktonic foraminifera Globigerina bulloides collected from tow samples along a transect from the equatorial Indian ocean to the Southern Ocean (45°E and 80°E and 10°N to 53°S) were analysed and compared with the equilibrium δ 18 O and δ 13 C values of calcite calculated using the temperature and isotopic composition of the water column. The results agree within ~0.25‰ for the region between 10°N and 40°S and 75–200 m water depth which is considered to be the habitat of Globigerina bulloides. Further south (from 40°S to 55°S), however, the measured δ 18 O and δ 13 C values are higher than the expected values by ~2‰ and ~1‰ respectively. These enrichments can be attributed to either a 'vital effect' or a higher calcification rate. An interesting pattern of increase in the δ 13 C(DIC) value of the surface water with latitude is observed between 35°S and~ 60°S, with a peak at~ 42°S. This can be caused by increased organic matter production and associated removal. A simple model accounting for the increase in the δ 13 C(DIC) values is proposed which fits well with the observed chlorophyll abundance as a function of latitude. Isotopic compositions of planktonic foraminifera are commonly used in the reconstruction of past oceanographic conditions but their reliability as environmental index depends on assumption of equilibrium condition at the time of growth and absence of subsequent alteration. Investigations on tow samples 1–4 and samples from the sediment trap 5–8 established a link between the geographical position and depth range of several planktonic species. Validation of the isotopic composition of Globigerina bulloides as a paleoclimate proxy was demonstrated by comparison of results of foraminiferal shell samples recovered by net from the water column and that from sediment core top samples. This comparison assumes that core top samples represents a time after the last glacial period when the oceanic environment remained relatively warm and stable and did not suffer any major changes 9. It is known that G. bulloides is sensitive to oceanographic change from the results of its increased abundance due to changes in the monsoonal activity during the Holocene 10. The G. bulloides proxy has been calibrated using modern sea-floor samples 11 and sediment trap time series 12 , and has been tested over a range of timescales 10. To generate long time series of oceanographic conditions from the geochemical analysis of fauna it is important to know how well the planktonic foraminifers preserve the signature of water properties. The planktonic foraminifera species are mostly confined to the photic zone but the exact depth habitat inside that zone depends on their temperature and salinity preferences. Expected isotopic composition of a species can only be calculated if we know their depth habitat. Based on observations of the tow and core top samples the optimum growth preferences of G. bulloides species are at a temperature of 13.4 °C and a salinity of 34.8PSU 13. In the Southern Ocean (SO) these values correspond to a depth of 50–100 m. This depth range is also commonly associated with the region of high chlorophyll and organic productivity 14,15. However, even though the G. bulloi-des inhabits mainly the mixed layer 2,14,16,17 , their presence has been recorded up to about 200 m. Studies from the Mediterranean region 18–20 showed that G. bulloides occurs over a large range of depth from 20 to 200 m in spring. Furthermore, there are recent suggestions that its calcification continues to depths even greater than 200 m 21 and

To understand the ecological preference, and timing and cause(s) of disappearance of S. lepidula, we analysed Neogene record of this taxon from Ocean Drilling Programme and Deep Sea Drilling Project sites located at bathyal to abyssal depths in the Atlantic and Indian oceans. Population plots of this species at various sites reveal that this taxon showed a substantial increase during the warm late Oligocene to the middle Miocene and suffered a major decline across the middle Miocene cooling event (15-13 Myr). S. lepidula disappeared at ~0.6 Myr very close to the MPT (0.9-0.8 Myr) from the Indian and Atlantic oceans, coinciding with a change from a 40 to 100 Kyr world with amplified ice-age cycles. We suggest that high-amplitude glacial cycles, frigid deep-water temperatures and strong circulation drove S. lepidula to nearly disappear across the MPT.

Stem cell therapy for myocardial tissue repair is limited by the poor survival of transplanted cells, possibly because of inadequate supply of oxygen and nutrients. The purpose of this study was to assess the oxygenation level and functional recovery after allogenic transplantation of mesenchymal stem cells (MSC) in a rat model of myocardial infarction (MI). Myocardial oxygen tension (Po2) was measured by electron paramagnetic resonance oximetry using an implantable oxygen-sensing spin probe (OxySpin). MSCs incubated with OxySpins showed substantial uptake of the probe without affecting its oxygen sensitivity or calibration. The cells internalized with OxySpins were able to differentiate into osteogenic, adipogenic, cardiomyocyte, and endothelial cell lineages. The labeled cells tested positive for CD44 and CD29 markers and negative for the hematopoietic markers CD14 and CD45. For the in vivo studies, MI was induced in rats by permanently ligating the left anterior descending corona...

This study describes and illustrates the evolution of deep-sea benthic foraminifera from the Blake Ridge during the late Neogene. In total, 305 species of benthic foraminifera belonging to 107 genera were identified. The Blake Ridge receives fine-grained nannofossil-bearing hemipelagic sediments, transported from the Canadian continental margin by the Deep Western Boundary Undercurrent (DWBUC). We thus presume that changes in benthic foraminifera at Ocean Drilling Program (ODP) sites 991A, 994C, 995A and B and 997A reflect mainly changes in the intensity of the DWBUC, which is closely related to North Atlantic Deep Water (NADW) production. However, the dominance of Uvigerina peregrina, U. proboscidea and Cassidulina carinata during the late Miocene in all the holes suggests an increased influence of Southern Component Waters in the Blake Ridge region. During the early Pliocene (4.8-2.8 Ma) in all the sites benthic faunal assemblages suggest that there was an increased transport of organic-rich sediments by the DWBUC from the Canadian margin to the Blake Ridge, driven by increased production of NADW. During this time the species diversity (Sanders' rarefied values) was low. In the younger interval (since 2.8 Ma), the faunal data suggest less transport of organic-rich sediments to the Blake Ridge, which appears to be related to weakening of the DWBUC during cold intervals. An increase in species diversity at 3 Ma probably resulted from decreased population of bacteria due to low organic matter and/or less competition. In the late Pleistocene (c. 0.6 Ma), Stilostomella lepidula became extinct in all the studied holes, suggesting that this species may have possessed a mode of feeding which no longer existed in the cold, well-oxygenated oceans of the present.

The tectonically driven closure of tropical seaways during the Pliocene epoch (∼5-2 million years (Myr) ago) altered ocean circulation and affected the evolution of climate. Plate tectonic reconstructions show that the main reorganization of one such seaway, the Indonesian Gateway, occurred between 4 and 3 Myr ago. Model simulations have suggested that this would have triggered a switch in the source of waters feeding the Indonesian throughflow into the Indian Ocean, from the warm salty waters of the South Pacific Ocean to the cool and relatively fresh waters of the North Pacific Ocean. Here we use paired measurements of the δ 18 O and Mg/Ca ratios of planktonic foraminifera to reconstruct the thermal structure of the eastern tropical Indian Ocean from 5.5 to 2 Myr ago. We find that sea surface conditions remained relatively stable throughout the interval, whereas subsurface waters freshened and cooled by about 4 • C between 3.5 and 2.95 Myr ago. We suggest that the restriction of the Indonesian Gateway led to the cooling and shoaling of the thermocline in the tropical Indian Ocean. We conclude that this tectonic reorganization contributed to the global shoaling of the thermocline recorded during the Pliocene epoch, possibly contributing to the development of the equatorial eastern Pacific cold tongue.

Rapid climatic shifts across the last glacial to Holocene transition are pervasive feature of the North Atlantic as well as low latitude proxy archives. Our decadal to centennial scale record of summer monsoon proxy Globigerina bulloides from rapidly accumulating sediments from Hole 723A, Arabian Sea shows two distinct intervals of weak summer monsoon wind coinciding with cold periods within Å llerød inerstadial of the North Atlantic named here as IACP-A1 and IACP-A2 and dated (within dating uncertainties) at 13.5 and 13.3 calibrated kilo years before the present (cal kyr BP), respectively. Spectral analysis of the Globigerina bulloides time series for the segment 13.6-13.1 kyr (Å llerød period) reveals a strong solar 208-year cycle also known as de Vries or Suess cycle, suggesting that the centennial scale variability in Indian summer monsoon winds during the Å llerød inerstadial was driven by changes in the solar irradiance through stratospheric-tropospheric interactions. T he Indian or South Asian monsoon is a fully coupled ocean-land-atmosphere feature marked by seasonal wind reversals which drive significant biogeochemical changes in the Arabian Sea. The Indian summer monsoon (ISM), also known as southwest monsoon, has a direct bearing on the socioeconomic conditions of people of South Asia which houses one-third of world population. The sensible heating of the land and troposphere during boreal summer has been suggested to intensify the land-sea thermal contrast that drives the ISM wind field 1. Recent climate models suggest that by removing Tibet, the monsoon largely remains unaffected provided the narrow orography of the Himalaya was preserved 2. These authors 2 suggest that monsoon is also sensitive to changes in surface heat fluxes from non-elevated regions of the Indian landmass as well as to changes in heat fluxes from adjacent elevated regions. Recent studies establish centennial to millennial scale climate connections between North Atlantic climate and ISM during the last glacial and the Holocene with dry monsoon phases aligned with intervals of cold spells in the North Atlantic 3-5. The transition from the last glacial to the Holocene assumes great significance in understanding how Earth's climate system can abruptly switch from one mode to another. The most detailed records of this transition are found in the North Atlantic 6 , the Arabian Sea 3 and China 7 , indicating that such shifts were pervasive throughout the Northern Hemisphere as well as the tropics since the last glacial period. In monsoonal Asia, such abrupt events have been observed in the East Asian monsoon records from the Hulu 7 and Dongge 8 caves of China, and Indian monsoon records from the Pakistan Margin 3 and Timta cave of India 9. What drives centennial or millennial changes in the monsoon is still debatable, although sun has been suggested as by far the most important driving force 10-12. The sun-climate link has been intensely debated in recent years 13,14 , though the idea that changes in solar activity may affect the Earth's climate was first discussed by Herschel 15. There is a growing realization that Sun plays an important role in driving small scale changes in the climate as is evident in numerous Holocene paleoclimate records 4,16,17. It has been suggested that the Asian monsoon could be sensitive to small changes in solar output 5,10-12. To understand if pronounced centennial changes in the ISM were related to solar variability, we analyzed summer monsoon wind record of 14-11 kyr period (covering the Å llerød period) from biogenic sediments of the Oman margin, northwest Arabian Sea where biological activity is elevated during summer monsoon season 18. We further investigate if changes in the monsoon were more rapid during warm intervals when solar activity was high 12 .