Earth and Planetary Science

Keywords: effective elastic thickness lithospheric structure of Africa tectonism and mantle processes Detailed information on lateral variations in lithospheric properties can aid in understanding how surface deformation relates to deep Earth processes. The effective elastic thickness, T e , of the lithosphere is a proxy for lithospheric strength. Here, we present a new T e map of the African lithosphere estimated from coherence analysis of topography and Bouguer anomaly data. The latter data set derives from the EGM 2008 model, the highest resolution gravity database over Africa, enabling a significant improvement in lateral resolution of T e . The methodology used for T e estimation improves upon earlier approaches by optimally combining estimates from several different window sizes and correcting for an estimation bias term. Our analysis finds that T e is high,~100 km, in the West African, Congo, Kalahari and Tanzania cratons. Of these, the Kalahari exhibits the lowest T e . Based in part on published seismic and mineral physics constraints, we suggest this may reflect modification of Kalahari lithosphere by anomalously hot asthenospheric mantle. Similarly, the Tanzania craton exhibits relatively lower T e east of Lake Victoria, where a centre of seismic radial anisotropy beneath the craton has been located and identified with a plume head, thus suggesting that here too, low T e reflects modification of cratonic lithosphere by an underlying hot mantle. The lowest T e in Africa occurs in the Afar and Main Ethiopian rifts, where lithospheric extension is maximum. In the western Ethiopian plateau a local T e minimum coincides with published images of a low P and S seismic velocity anomaly extending to~400 km depth. Finally, the Darfur, Tibesti, Hoggar and Cameroon line volcanic provinces are characterised by low T e and no deep-seated seismic anomalies in the mantle. Corridors of relatively low T e connect these volcanic provinces to the local T e minima within the western Ethiopian plateau. We interpret the low T e to indicate thinner lithosphere within the corridors than in the surrounding cratons. We speculate that these corridors may provide potential conduits for hot asthenospheric material to flow from the western Ethiopian plateau to the volcanic provinces of central and western Africa.

The Vema Transverse Ridge (VTR) is a prominent, long and narrow topographic anomaly that runs for over 300 km along a sea floor spreading flow line south of the Vema transform at 118 N in the Atlantic. It rises abruptly about 140 km from the axis of the Mid-Atlantic Ridge (MAR) in~10 Myr old crust and runs continuously up to~25 Myr old crust. It reaches over 3 km above the predicted lithospheric thermal contraction level. It is absent in crust younger than 10 Myr; thus, the uplift of the VTR must have ended roughly 10 Ma. The VTR is interpreted as the exposed edge of a flexured and uplifted slab of oceanic lithosphere that was generated at an 80 km long MAR segment. Based on satellite gravimetry imagery this MAR segment was born roughly 50 Ma and increased its length at an average rate of 1.6 mm/yr. Multibeam data show that the MAR-parallel sea floor fabric south of the VTR shifts its orientation by 58 to 108 clockwise in~11-12 Myr old crust, indicating a change at that time of the orientation of the MAR axis and of the position of the Euler rotation pole. This change caused extension normal to the transform, followed between 12 and 10 Ma by flexure of the edge of the lithospheric slab, uplift of the VTR at a rate of 2 to 4 mm/yr, and exposure of a lithospheric section (Vema Lithospheric Section or VLS) at the northern edge of the slab, parallel to the Vema transform. Ages of pelagic carbonates encrusting ultramafic rocks sampled at the base of the VLS at different distances from the MAR axis suggest that the entire VTR rose vertically as a single block within the active transform offset. A 50 km long portion of the crest of the VTR rose above sea level, subsided, was truncated at sea level and covered by a carbonate platform. Subaerial and submarine erosion has gradually removed material from the top of the VTR and has modified its slopes. Spreading half rate of the crust south of the transform decreased from 17.2 mm/yr between 26 and 19 Ma to~16.9 mm/yr between 19 and~10 Ma, to~13.6 mm/yr from 10 Ma to present. The slowing down of spreading occurred close in time to the change in ridge/transform geometry, suggesting that the two events are related. A numerical model relates lithospheric flexure to extension normal to the transform, suggesting that the extent of the uplift depends on the thickness of the brittle layer, consistent with the observed greater uplift of the older lithosphere along the VTR.

Woodleigh is a recently discovered impact structure with a diameter of 120 km, and thereby represents the third largest proven Phanerozoic impact structure known after Morocweng and Chicxulub. K-Ar isotopic studies of fine-grained authigenic illitic clay minerals (<2 μm), considered to be impact-induced hydrothermal alteration products, indicate a Late Devonian (359±4 Ma) age for the impact. Other evidence reported for Late Devonian extraterrestrial impacts include the strong iridium anomaly in the Canning Basin, Western Australia, and microtektites and elemental anomalies (including iridium) in South China. Given the large diameter of the Woodleigh impact structure and its relative proximity to iridium anomalies also of Late Devonian age in eastern Gondwana basins, environmental effects of the Woodleigh impact event are a likely contributor to a biotic crisis in the Late Devonian.

... K–Ar dating has placed a lower limit of 0.6 Ma on the age of Soufriere [35 ... Crustal contamination is also well documented from some of the central Lesser Antilles islands such as Martinique [30] and [40]where the lavas define a good positive array on diagrams of SiO 2 versus 87 ...

Volcanogenic massive sulphide (VMS) deposits represent the fossil analogues of the active hydrothermal vents in the seafloor found at oceanic spreading centres (Galley et al., 2007). Fluid inclusion (FI) studies of both active ("black smokers"; e.g. Vanko et al., 2004) and fossil (e.g., Pisutha-Arnond & Ohmoto, 1983) VMS systems have provided much information on the physical and chemical conditions of formation of these deposits. The vast majority of all FI studied from VMS deposits are hosted in quartz. Primary inclusions in quartz are trapped as quartz precipitates from hydrothermal fluid-primary inclusions are unlikely to be trapped where and when quartz is being dissolved. Therefore conditions of quartz dissolution will be underrepresented in the primary inclusion record (although those conditions may be preserved in secondary inclusions). The properties of quartzhosted FI can provide information on the physical and chemical conditions of quartz precipitation. Ideally those conditions should be related to hydrothermal processes, but sub-seafloor processes cannot be directly observed, and must therefore be modelled and/or inferred. The occurrence of phase separation in sub-seafloor hydrothermal systems is now widely recognized based on vent chemistry data (e.g., Von Damm, 2004), although less is known about how sub-seafloor immiscibility affects fluid-rock interaction in VMS deposits. Fluid inclusion assemblages in quartz from active VMS-forming systems sometimes contain coexisting liquid-rich and vapour-rich inclusions, revealing that the host quartz was precipitated from immiscible fluids (de Ronde, 1995; Vanko et al., 2004). Halite-bearing inclusions are commonly found in VMS quartz, and may represent brine generated during phase separation, although they are usually found without coexisting vapour-rich inclusions.

Application of cosmogenic radionuclide 22 Na to limnological research was first successfully performed in the Lake Biwa system, Japan. The 22 Na was determined from large water samples of more than 500 L by using the ultra low-background Gedetector installed at underground (Ogoya Lab.) after simple chemical separation. Extremely low 22 Na concentrations ranging from 19.9 to 32.7 mBq/m 3 and from 27.4 to 38.3 mBq/m 3 were found in the lake and river water samples, respectively. Mass balances of 22 Na from the watershed to river and lake were constructed by considering the atmospheric deposition of 22 Na. The mean residence times of 22 Na in the southern and northern basins of Lake Biwa were estimated as about 18 days and 5.4 years, respectively. Furthermore, the mean residence time of this atmospheric nuclide in the watershed was evaluated as about 7.3 years, whose value may be helpful in tracing the fate of contaminants with similar chemical properties in the watershed. The quantity of groundwater flow into the lake was also roughly estimated to be 1.6Â10 9 m 3 /yr from the specific activity of 22 Na/Na.

Intra-oceanic volcanic arcs mark the boundaries between converging lithospheric plates where subduction produces volcanic and tectonic activity that ensures a steady supply of magmatic heat and hydrothermal fluids to the seafloor. Here we report on the first broad and systematic survey of hydrothermal emissions generated along a submarine arc front. More than half (seven of 13) of the volcanoes surveyed along 260 km of the southern Kermadec arc, NE of New Zealand, are hydrothermally active. Our results indicate that volcanic arcs represent a previously unheeded but potentially extensive source of shallow ( 6 2 km water depth) vent fields expelling fluids of a unique and heterogeneous composition into the oceans. ß

Detrital modes of modern Nile sands, together with estimates of sediment volumes trapped in Sudanese reservoirs, allow us to calculate sediment loads of major tributaries (Blue Nile, White Nile, Atbara) and erosion rates in the Nile catchment. A tridimensional array of high-resolution bulk-petrography and heavy-mineral data was obtained on both levee (suspended load) and bar (bedload) deposits, analysed separately for each grain-size subclass at 0.5Φ intervals. From available information on sediments stored in the Roseires, Khashm el Girba and Lake Nasser reservoirs between 1964 and 1990, the total Nile load is reassessed at 230 ± 20 10 6 t/a, an estimate two to four times higher than figures reported so far, on which previous estimates of sediment yields and erosion rates were based. Of such huge amount of detritus, 82 ± 10 10 6 t/a are contributed by River Atbara, which carries more volcanic rock fragments, brown augite and olivine from basaltic rocks, and 140 ± 20 10 6 t/a by the Blue Nile, which carries more K-feldspar and hornblende from amphibolite-facies basement rocks. The additional ≤10 7 t/a of almost purely quartzose sediments supplied by the rest of the Nile catchment, corresponding to insignificant average yields and erosion rates, represent the stable residue which survived extreme subequatorial weathering in southern Sudan swamps (White Nile, Bahr ez Zeraf, and Sobat sands) or fluvial and eolian recycling of ancient quartzarenites in hyperarid climates (Nubian sands). Sediment production is thus markedly focused on Ethiopian rift highlands, where rainfall is concentrated in a single July-August peak. High average yields and erosion rates (800 ± 150 t/km 2 a, 0.29 ± 0.05 mm/a) partly reflect anthropically-accelerated erosion caused by deforestation and intensive land use, and cannot be extrapolated far in the past. Erosion patterns may have changed repeatedly during Quaternary climatic oscillations, and possibly also in the longer term during the multistage rift-related events which, since impingement of the Afar plume and eruption of flood basalts in the Oligocene, caused elevated topography and monsoonal climate in Ethiopia.

Molecular biomarkers (C 37 alkenones, n-nonacosane and n-hexacosanol) and TOC are used together with benthic N 18 O and N 13 C data to document the hydrographic response of the western Mediterranean Sea to rapid climatic variability. These proxies are recorded in core MD 95-2043 (Alboran Sea) affording the study of the DansgaardÔ eschger (D^O) and Heinrich (HE) variability during the last glacial period. The results suggest that rapid changes in the western Mediterranean thermohaline circulation occurred in parallel to sea surface temperature oscillations. Enhanced deep water ventilation occurred during cold intervals (HE and D^O Stadials) probably driven by a strengthening of north-westerly wind over the north-western Mediterranean Sea. In contrast, decreased intensity of the thermohaline circulation is detected during warm intervals (D^O Interstadials) which led to low oxygenated deep water masses and better preservation of the organic matter in the sediment. ß

Extensive field investigations along the Yarlung^Zangbo suture zone in southern Tibet reveal the presence of now fragmented remnants of a south-facing intra-oceanic subduction system. This system developed within Tethys during the Cretaceous. The associated arc, forearc ophiolite, and subduction complex were emplaced onto the leading edge of India at the end of the Cretaceous. Rapid sedimentation in oblique-slip basins and disruption of water-saturated sediments into mëlange was widespread and concomitant with ophiolite emplacement. We describe the tectonic entities that developed during this previously unrecognized phase of Tethys^Tibet evolution and present a new model for the evolution of this portion of Tibet. ß

Noctis Labyrinthus (Mars) is characterized by many tectonic features, which represent brittle deformation of the crust. This tectonic setting was analysed by remote sensing of the Viking Mars Digital Image Model (MDIM) mosaic and Mars Orbiter Camera (MOC) global mosaic, in order to identify deformational events. The main features are normal faults producing horst-graben structures, strike-slip faults, and related en-echelon and pull-apart basins. Using the criterion of cross-cutting relationships and analysis of secondary structures, to infer sense of movement of faults, two deformational phases were identiÿed in the Noctis Labyrinthus area. The ÿrst, D1, located mainly in the northern part, is characterized by transtensional faults (Noachian). The second, D2, recorded in the southern part of the Noctis Labyrinthus by an orthorhombic extensional fault pattern along NNE and WNW trends, is related to the Valles Marineris formation (Late Noachian-Early Hesperian). A third tectonic event, D3, represented by the partly known dextral NW strike-slip faults cross-cutting the Valles Marineris Canyon System

The Chicxulub impact crater in Mexico is the site of the impact purported to have caused mass extinctions at the Cretaceous/Tertiary (K/T) boundary. 2-D hydrocode modeling of the impact, coupled with studies of the impact site geology, indicate that between 0.4 and 7.0 × 10 17 g of sulfur were vaporized by the impact into anhydrite target rocks. A small portion of the sulfur was released as SO 3 or SO 4, which converted rapidly into H 2SO 4 aerosol and fell as acid rain. A radiative transfer model, coupled with a model of coagulation indicates that the aerosol prolonged the initial blackout period caused by impact dust only if the aerosol contained impurities. A larger portion of sulfur was released as SO 2, which converted to aerosol slowly, due to the rate-limiting oxidation of SO 2. Our radiative transfer calculations, combined with rates of acid production, coagulation, and diffusion indicate that solar transmission was reduced to 10-20% of normal for a period of 8-13 yr. This reduction produced a climate forcing (cooling) of -300 Wm -2, which far exceeded the +8 Wm -2 greenhouse warming, caused by the CO 2 released through the vaporization of carbonates, and therefore produced a decade of freezing and near-freezing temperatures. Several decades of moderate warming followed the decade of severe cooling due to the long residence time of CO 2. The prolonged impact winter may have been a major cause of the K/T extinctions.

We report results from an investigation of the geologic processes controlling hydrothermal activity along the previously-unstudied southern Mid-Atlantic Ridge (3-7°S). Our study employed the NOC (UK) deep-tow sidescan sonar instrument, TOBI, in concert with the WHOI (USA) autonomous underwater vehicle, ABE, to collect information concerning hydrothermal plume distributions in the water column co-registered with geologic investigations of the underlying seafloor. Two areas of high-temperature hydrothermal venting were identified. The first was situated in a non-transform discontinuity (NTD) between two adjacent secondorder ridge-segments near 4°02′S, distant from any neovolcanic activity. This geologic setting is very similar to that of the ultramafic-hosted and tectonically-controlled Rainbow vent-site on the northern Mid-Atlantic Ridge. The second site was located at 4°48′S at the axial-summit centre of a second-order ridge-segment. There, high-temperature venting is hosted in an ∼ 18 km 2 area of young lava flows which in some cases are observed to have flowed over and engulfed pre-existing chemosynthetic vent-fauna. In both appearance and extent, these lava flows are directly reminiscent of those emplaced in Winter 2005−06 at the East Pacific Rise, 9°50′N and reference to global seismic catalogues reveals that a swarm of large (M 4.6−5.6) seismic events was centred on the 5°S segment over a ∼ 24 h period in late June 2002, perhaps indicating the precise timing of this volcanic eruptive episode. Temperature measurements at one of the vents found directly adjacent to the fresh lava flows at 5°S MAR (Turtle Pits) have subsequently revealed vent-fluids that are actively phase separating under conditions very close to the Critical Point for seawater, at ∼ 3000 m depth and 407°C: the hottest vent-fluids yet reported from anywhere along the global ridge crest.

Elevated ultraviolet irradiance (UVR, 280-400 nm) damages DNA and induces reorganisation within biological communities at the Earth's surface. Southern high latitude aquatic ecosystems may be particularly susceptible because of low stratospheric ozone levels and extremely low contents of photoprotective dissolved organic matter (DOM). Surveys of shallow lakes and ponds in eastern Antarctica show that cyanobacteria survive elevated UVR exposure by increasing extra-cellular concentrations of photoprotective compounds, which are preserved in sediments together with photosynthetic pigments. Thus, reconstruction of long-term changes in biological UVR receipt, to provide a context for evaluating the long-term significance of recent changes in ozone column depth, is feasible in Antarctic settings. The sediment in Lake Reid (698 23V S, 768 53V E), Antarctica, spans the late-Pleistocene and contains UVR-absorbing pigments from benthic cyanobacteria. Here we show that mean exposure of these benthic cyanobacteria to UVR during the last glacial was more than three times higher than during the Holocene, likely due to short periods of photosynthetic activity coinciding with relatively high UVR fluxes, or due to increased UVR transmission to the Earth's surface resulting from changes in external factors such as stratospheric ozone levels, cloud cover and surface albedo. D

Transformations of magnetite (Fe II Fe 2 III O 4 ) to hematite (Fe 2 III O 3 ) (and vice versa) have been thought by many scientists and engineers to require molecular O 2 and/or H 2 . Thus, the presence of magnetite and/or hematite in rocks has been linked to a specific oxidation environment. However, the availability of reductants or oxidants in many geologic and industrial environments appears to have been too low to account for the transformations of iron oxides through redox reactions. Here, we report the results of hydrothermal experiments in mildly acidic and H 2 -rich aqueous solutions at 150°C, which demonstrate that transformations of magnetite to hematite, and hematite to magnetite, occur rapidly without involving molecular O 2 or H 2 :

Electron microscopy and biomolecular methods have been used to describe and identify microbial communities inhabiting the glassy margins of ocean floor basalts. The investigated samples were collected from a neovolcanic ridge and from older, sediment-covered lava flows in the rift valley of the Knipovich Ridge at a water depth around 3500 m and an ambient seawater temperature of 30.7³C. Successive stages from incipient microbial colonisation, to welldeveloped biofilms occur on fracture surfaces in the glassy margins. Observed microbial morphologies are various filamentous, coccoidal, oval, rod-shaped and stalked forms. Etch marks in the fresh glass, with form and size resembling the attached microbes, are common. Precipitation of alteration products around microbes has developed hollow subspherical and filamentous structures. These precipitates are often enriched in Fe and Mn. The presence of branching and twisted stalks that resemble those of the iron-oxidising Gallionella, indicate that reduced iron may be utilised in an energy metabolic process. Analysis of 16S-rRNA gene sequences from microbes present in the rock samples, show that the bacterial population inhabiting these samples cluster within the Q-and O-Proteobacteria and the Cytophaga/Flexibacter/Bacteroides subdivision of the Bacteria, while the Archaea all belong to the Crenarchaeota kingdom. This microbial population appears to be characteristic for the rock and their closest relatives have previously been reported from cold marine waters in the Arctic and Antarctic, deep-sea sediments and hydrothermal environments. ß

The Australian continent is characterised by an extremely variable surficial geochemistry, reflecting the varied lithology of Australian basement rocks. Samples representative of Australian aeolian dust have been collected in (1) regions where meteorological records, satellite observation and wind erosion modelling systems have indicated frequent dust activity today (mainly the Lake Eyre Basin), and (2) from deposits of mixed dust materials. The 87Sr/86Sr and 143Nd/144Nd isotopic composition of the fine (&lt; 5 μm) fraction of Australian dust samples was measured for comparison with the Sr and Nd isotopic composition of fine aeolian dust that reached the interior of the East Antarctic Plateau. The isotopic field for Australian dust is characterised by 87Sr/86Sr ratios ranging from 0.709 to 0.732 and εNd(0) between − 3 and − 15. The low Sr radiogenic values and εNd(0) of − 3 obtained for Lake Eyre samples are explained by the lithology of the Lake Eyre catchment showing a dominance o...

Submarine volcanic glass He, Ne and Ar data from the Pacific-Antarctic-Rise at its intersection with the Foundation Seamount Chain have been obtained to further elucidate one of the main outstanding problems in plume-ridge interaction studies: the physical state in which mantle flow and mixing occur in those settings. Mixing of plume mantle and mid-ocean ridge basalt source material may either be in the form of two solids, of solid-melt or of two melt phases only. The positive correlation of 4 He/ 40 Ar* with 206 Pb/ 204 Pb as well as the negative correlation of 4 He/ 40 Ar* with 40 Ar* and 4 He concentrations, combined with a lack of correlation between 4 He/ 40 Ar* and ridge depth or MgO concentration, indicate that the enriched mantle plume material has been extensively degassed prior to mixing with the mid-ocean ridge source material. Degassing of the plume source and mid-ocean ridge source material prior to mixing is also suggested by the He versus Pb isotope systematics. However, the occurrence of degassing processes requires the existence of melts, implying that mixing between the plume and the mid-ocean ridge material occurs in the physical form of melts.

High precision TIMS 230Th/ 232Th isotope ratios are presented from a suite of lavas which span the length of the Lesser Antilles island arc. Compositions vary from low K, tholeiitic lavas with low *'Sr/ 86Sr in the north, to high K, talc-alkaline to alkalic lavas with higher s'Sr/ ?Sr in the south. The northern lavas are characterised by tz3'Th/ 238U) < 1 whereas those from the south tend towards secular equilibrium and occasionally have (230Th/ 238U) > 1. A three-component model is required for magma genesis in the Lesser Antilles. Sediments from the subducting slab melt and variably enrich the mantle wedge, while the subducting oceanic crust dehydrates, releasing fluids enriched in U, Ba, Sr and K, but with negligible Th and low "Sr/ *?Sr, which promote partial melting in the wedge. Ta/Zr increases with " Sr/ 86Sr southwards along the arc and this is inferred to reflect increasing enrichment of the mantle wedge through the addition of partial melts of subducted sediment. Mass balance calculations are consistent with a relatively constant fluid flux (except for U) and little variation in the degree of partial melting (lo-15%) along the arc, and they suggest that the sediment contribution to the arc lavas increases from -2% in the north to -15% in the south. In the northern parts of the arc, the addition of U by these fluids overprints any increases in Th/U that might have been caused by partial melting, and results in lavas with (230Th/ 238U) < 1. Further south, the fluid signature is swamped by partial melts of the subducted sediments, and the (230Th/ 238U) ratios tend towards 1. Assuming that (230Th/ 238U) ratios < 1 reflect the preferential mobility of U in aqueous fluids, the bulk of the LIL element abundances, and the elevated "Sr/ ?3r ratios in the talc-alkaline and alkalic lavas, were not transported by subduction zone fluids. A three-component mixing model is developed to calculate (230Th/232Th) ratios at the time of formation of the measured U/Th. The time required for radioactive decay from these calculated ratios to the measured (230Th/ 232Th) ratios provides an upper limit on the transport time for the relatively high U/Th fluid component through the wedge of -90000 yr. If -50000 yr U-Th isochrons from Soufritre on St. Vincent reflect typical magma chamber residence times for this island arc, this leaves ascent rates > 1 m yr-', -40000 yr for transport from the slab to the crust. Such constraints require which imply channelled flow through the mantle wedge.

The climate of the Eastern Mediterranean region of the last 60 ky was determined by a high resolution study of the oxygen and carbon isotopic composition (1500 measurement pairs) of speleothems from the Soreq cave, Israel, with chronology provided by 53 precise 230Th–234U (TIMS) ages. The high precision of the speleothem TIMS ages permits us to determine the timing of

Chemical analyses and Raman micro-spectroscopy have identified whitlockite (water-and halogen-free phosphate) in mantle xenoliths from Siberia. Whitlockite has not previously been reported from terrestrial mantle-derived rocks, but is the most common accessory phosphate in meteorites and igneous rocks from Mars and the Moon. The presence of the 'anhydrous' whitlockite, together with the breakdown of 'hydrous' accessory minerals (amphibole, phlogopite) in the same xenoliths, indicates that portions of the terrestrial upper mantle may be nearly as low in water and halogens as in inner parts of the smaller solar system bodies, regardless of enrichments of other highly mobile components (phosphorus, alkalis). Whitlockite may be an important host for some lithophile trace elements in those portions of the terrestrial mantle. It contains up to 3 times more rare earth elements than coexisting apatite but less Sr, Ba and U while Th abundances are similar. Thus, trace element abundances, patterns and ratios (e.g. Sr/Nd, Th/U) in whitlockite-bearing mantle rocks and coexisting fluids may be distinct from those for mantle rocks containing only apatite and/or other 'hydrous' minerals. Several generations of both whitlockite and apatite with different textural positions and abundances of Na, Mg, Sr and LREE were identified in some of the xenoliths. Furthermore, precipitation of the phosphates was accompanied by the formation of a distinct generation of clinopyroxene, which contains much less Zr (up to 10 times) but more LREE than clinopyroxenes formed in previous metasomatic episodes.

The new gravity and magnetic data recorded along a profile in the Sikkim, NE Himalaya are combined with the existing data from Tibet, Bangladesh and India, to delineate the crustal structure in this part of Himalaya. Modelling of gravity data, constrained from seismic results suggests that long wavelength gravity anomalies arise due to variations in the depth of Moho (36 to 74 km), which are caused by flexed lithosphere of effective elastic thickness of ∼ 50 ± 10 km. Simultaneous modelling of magnetic anomalies and short wave-length gravity anomalies reveals that (a) the magnetic anomalies observed over the Lesser Himalaya and the Higher Himalaya Crystalline rocks might be caused by remnant magnetisation with inclination I = − 18°± 8°and declination D = 147°± 10°, which is in conformity with the palaeomagnetic results. These magnetic parameters correspond to~35 ± 10 Ma age of magnetic direction and suggest that the rocks might have acquired magnetisation during cooling period of metamorphism, (b) low grade meta-sediments of the Lesser Himalaya extend up to 12 km depth and thins on either sides forming a bowl shaped geometry and (c) relative gravity high in the Bengal basin might be caused by intrusion of the Rajmahal volcanics. Modelling has also provided constraint on the geometry of the north dipping thrusts.

Rare asteroidal vesicular basalts have previously been thought to form in surficial lava flows with CO as the vesicle-forming gas. However, vesicular lava flows are unlikely on small, airless bodies such as asteroids. To unravel the origin of these rocks, we analyzed vesicle sizes and abundances for two angrites and two eucrites using high-resolution X-ray computed tomography and conducted numerical modeling of bubble formation in a dike of ascending magma. Modeling results indicate that thin (b 30 cm wide) dikes are trapped at ∼ 5 km depth where ∼ 75 ppm of CO and CO 2 contribute equally to vesicle formation. Vesicular eucrites were metamorphosed in this deep-seated environment, the gas was lost, and they were excavated by impacts. Published by Elsevier B.V.

Mesozoic continental arcs in the North American Cordillera were examined here to establish a baseline model for Phanerozoic continent formation. We combine new trace-element data on lower crustal xenoliths from the Mesozoic Sierra Nevada Batholith with an extensive grid-based geochemical map of the Peninsular Ranges Batholith, the southern equivalent of the Sierras. Collectively, these observations give a three-dimensional view of the crust, which permits the petrogenesis and tectonics of Phanerozoic crust formation to be linked in space and time. Subduction of the Farallon plate beneath North America during the Triassic to early Cretaceous was characterized by trench retreat and slab rollback because old and cold oceanic lithosphere was being subducted. This generated an extensional subduction zone, which created fringing island arcs just off the Paleozoic continental margin. However, as the age of the Farallon plate at the time of subduction decreased, the extensional environment waned, allowing the fringing island arc to accrete onto the continental margin. With continued subduction, a continental arc was born and a progressively more compressional environment developed as the age of subducting slab continued to young. Refinement into a felsic crust occurred after accretion, that is, during the continental arc stage, wherein a thickened crustal and lithospheric column permitted a longer differentiation column. New basaltic arc magmas underplate and intrude the accreted terrane, suture, and former continental margin. Interaction of these basaltic magmas with pre-existing crust and lithospheric mantle created garnet pyroxenitic mafic cumulates by fractional crystallization at depth as well as gabbroic and garnet pyroxenitic restites at shallower levels by melting of pre-existing lower crust. The complementary felsic plutons formed by these deep-seated differentiation processes rose into the upper crust, stitching together the accreted terrane, suture and former continental margin. The mafic cumulates and restites, owing to their high densities, eventually foundered into the mantle, leaving behind a more felsic crust. Our grid-based sampling allows us to estimate an unbiased average upper crustal composition for the Peninsular Ranges Batholith. Major and trace-element compositions are very similar to global continental crust averaged over space and time, but in detail, the Peninsular Ranges are slightly lower in compatible to mildly incompatible elements, MgO, Mg#, V, Sc, Co, and Cr. The compositional similarities suggest a strong arc component in global continental crust, but the slight discrepancies suggest that additional crust formation processes are also important in continent formation as a whole. Finally, the delaminated Sierran garnet pyroxenites have some of the lowest U/Pb ratios ever measured for silicate rocks. Such material, if recycled and stored in the deep mantle, would generate a reservoir with very unradiogenic Pb, providing one solution to the global Pb isotope paradox.

Via decrement of mass of planets, we can send the entire planets to far space orbital allocations. We can convert physical matter into energy, it can either get irradiated to outer space, get transmitted back to Earth's potential energy, get used as a self-propellant, or it can get used in a complex model of these systems; it decreases the mass of the planet. By conversion of the matter to energy, Earth will lose some mass that decreases the gravitational fields for Earth; the formulas of the current research are deduced to control the movements of the planets. Celestial bodies, like any other mechanical systems which follow, and are based on, the physical laws of mechanics and dynamical systems, follow these laws. So since the celestial object “A” exerts the “F” force on the celestial object “B”, the celestial object “B” exerts an interactive force “F” on the celestial object “A” also. All celestial objects exert gravitational influences on each other. Scientists believe, once upon a time, the Sun would be much hotter than what it is today. By that point, this high temperature leads to extinction of the entire existence of life on Earth. When the gravitational force changes, a space particle may either get departed from the other particle or come closer to the other particle.

Anomalous geomagnetic directions are recorded in the thermoremanent magnetisation (TRM) of alkali basalt lavas from the Auckland volcanic field, New Zealand. The concordance of paleomagnetic directions both in different sites from individual eruptive centres and in sites from several different centres, as well as their relatively short age span compared with that of the field as a whole, indicates that these anomalous directions have a geomagnetic origin. The directions, which are dated between approximately 25 ka and 50 ka, do not represent full reversals of the geomagnetic field and are interpreted as excursions. Very few excursions have been reported from the Southern Hemisphere; this is the first such record known from igneous rocks and further supports the notion that excursions are global phenomena. The excursions here are tentatively correlated with those reported from Lake Mungo, Mono Lake and Laschamp.

The transition from the Triassic to Jurassic Period, initiating the 'Age of the dinosaurs', approximately 200 Ma, is marked by a profound mass extinction with more than 50% genus loss in both marine and continental realms. This event closely coincides with a period of extensive volcanism in the Central Atlantic Magmatic Province (CAMP) associated with the initial break-up of Pangaea but a causal relationship is still debated. The Triassic-Jurassic (T-J) boundary is recently proposed in the marine record at the first occurrence datum of Jurassic ammonites, post-dating the extinction interval that concurs with two distinct perturbations in the carbon isotope record. The continental record shows a major palynological turnover together with a prominent change in tetrapod taxa, but a direct link to the marine events is still equivocal. Here we develop an accurate chronostratigraphic framework for the T-J boundary interval and establish detailed trans-Atlantic and marine-continental correlations by integrating astrochronology, paleomagnetism, basalt geochemistry and geobiology. We show that the oldest CAMP basalts are diachronous by 20 kyr across the Atlantic Ocean, and that these two volcanic pulses coincide with the end-Triassic extinction interval in the marine realm. Our results support the hypotheses of Phanerozoic mass extinctions resulting from emplacement of Large Igneous Provinces (LIPs) and provide crucial time constraints for numerical modelling of Triassic-Jurassic climate change and global carbon-cycle perturbations.

Detrital modes of modern Nile sands, together with estimates of sediment volumes trapped in Sudanese reservoirs, allow us to calculate sediment loads of major tributaries (Blue Nile, White Nile, Atbara) and erosion rates in the Nile catchment. A tridimensional array of high-resolution bulk-petrography and heavy-mineral data was obtained on both levee (suspended load) and bar (bedload) deposits, analysed separately for each grain-size subclass at 0.5Φ intervals. From available information on sediments stored in the Roseires, Khashm el Girba and Lake Nasser reservoirs between 1964 and 1990, the total Nile load is reassessed at 230 ± 20 10 6 t/a, an estimate two to four times higher than figures reported so far, on which previous estimates of sediment yields and erosion rates were based. Of such huge amount of detritus, 82 ± 10 10 6 t/a are contributed by River Atbara, which carries more volcanic rock fragments, brown augite and olivine from basaltic rocks, and 140 ± 20 10 6 t/a by the Blue Nile, which carries more K-feldspar and hornblende from amphibolite-facies basement rocks. The additional ≤10 7 t/a of almost purely quartzose sediments supplied by the rest of the Nile catchment, corresponding to insignificant average yields and erosion rates, represent the stable residue which survived extreme subequatorial weathering in southern Sudan swamps (White Nile, Bahr ez Zeraf, and Sobat sands) or fluvial and eolian recycling of ancient quartzarenites in hyperarid climates (Nubian sands).

The eruption of the Siberian Traps flood basalts has been invoked as a trigger for the catastrophic end-Permian mass extinction. Quantitative constraints on volatile degassing are critical to understanding the environmental consequences of volcanism. We measured sulfur, chlorine, and fluorine in melt inclusions from the Siberian Traps and found that concentrations of these volatiles in some magmas were anomalously high compared to other continental flood basalts. For the ten samples for which we present data, volatile concentrations in individual melt inclusions range from less than the detection limit to 0.51 wt.% S, 0.94 wt.% Cl, and 1.95 wt.% F. Degassing from the Siberian Traps released approximately~6300-7800 Gt S,~3400-8700 Gt Cl, and~7100-13,600 Gt F. These large volatile loads, if injected into the stratosphere, may have contributed to a drastic deterioration in global environmental conditions during the end-Permian.

Cores 255 and B-3GC from the southern and northern Okinawa Trough, respectively, were studied for determining the variability of the Kuroshio Current on centennial scales during the Holocene based on detailed AMS 14 C dates, stable isotope, and planktonic foraminiferal distribution. The main flow of the Kuroshio Current was inferred to reenter the Okinawa Trough at V7.3 calendar (cal.) kyr BP, leading to abrupt changes in sedimentation rate, remarkably increased abundance of the Kuroshio Current indicator Pulleniatina obliquiloculata, increased sea surface temperature (SST) and depth of thermocline (DOT). During V4.6^2.7 cal. kyr BP, the abundance of P. obliquiloculata sharply decreased, corresponding to a decreases in SST and DOT, implying that the influence of the Kuroshio Current weakened at that time, possibly as a result of the intensified winter monsoon. Significantly, the Kuroshio Current proxies (e.g. the difference in SST between the southern and northern Okinawa Trough) display periodicities of V1500 yr and V700^800 yr (ascribed to the second harmonic of the 1500 yr cycle in oceanic thermohaline circulation) during the Holocene. The Holocene events (at V0.6, 1.7, 3.3, 4.6, 5.9, 8.1, 9.4 cal. kyr BP) in the Okinawa Trough appear to be the most recent manifestation of the millennial scale climate cycle, recorded in the North Atlantic, Arabian Sea marine sediment cores and Greenland ice cores, suggesting global climatic tele-connections. ß

The first flowering plant fossils occur as rare, undiverse pollen grains in the Early Cretaceous (Valanginian-Hauterivian). Angiosperms diversified slowly during the Barremian-Aptian but rapidly during the Albian-Cenomanian. By the end of the Cretaceous, at least half of the living angiosperm orders were present, and angiosperms were greater than 70% of terrestrial plant species globally. The rapid diversification of the group, and its dominance in modern vegetation, has led to the idea that the Cretaceous radiation of angiosperms also represents their rise to vegetational dominance. Paleoecological data cast a different light on the Cretaceous radiation of angiosperms. Analyses of sedimentary environments indicate that angiosperms not only originated in unstable habitats but remained centered there through most of the Cretaceous. Morphology of leaves, seeds, and wood is consistent with the status of most Cretaceous angiosperms as herbs to small trees with early successional strategy. The diversification of flowering plants in the Cretaceous represents the evolution of a highly speciose clade of weeds but not necessarily a major change in global vegetation.

At the summit of Hydrate Ridge (ODP Sites 1249 and 1250), pore fluids are highly enriched in dissolved chloride (up to 1370 mM) in a zone that extends from near the sediment surface (~1 mbsf) to depths of 25F5 mbsf. Below this depth, brines give way to chloride values approaching seawater concentrations with lower chloride anomalies superimposed on baseline values. We developed a one dimensional, non-steady state, transport reaction model to simulate the observed chloride enrichment at Site 1249. Our model shows that in order to reach the observed high chloride values, methane must be transported in the gas phase from the depth of the BSR to the seafloor. Methane transport exclusively in the dissolved phase is not enough to form methane hydrate at the rates needed to generate the observed chloride enrichment. Methane transport in the gas phase is consistent with geophysical and logging data, estimates of gas pressure beneath the BSR, and observations of bubble plumes at the seafloor.

In the book, questions of Earth's craters exploration and origin of tektites on our planet are brought up. It is shown that our knowledge in this field remains limited so far and demand revision of the data interpretation.
In the context of the Tunguska 1908 phenomenon, we suppose correlations between the Perm LLSVPs Anomaly and the explosion of paleovolcano in Siberia on 30 June 1908. We discuss magnetic pulsations in Kiel, Germany observed from 27 till 30 June 1908, a variation of gravitational constant during the solar eclipse on 28 June
1908, and the discrepancy of Moon longitude at the beginning of the 20th century. The non-typical registrations in Tasmania in the period of the Tunguska 1908 phenomenon and his connection with the Perm LLSVPs anomalies provide a highly probable solution to one of the greatest mysteries of the previous century.

For astro- and geophysicists and a wide range of readers who are interested in meteorites and planetology.

This study explores a chemo-thermo-dynamic subduction zone model that solves for slab dehydration during subduction. We investigate how changes in the incoming plate's hydration and thermal structure may effect the efficiency of sub-arc water release from sediments, crust, and serpentinized mantle. We find that serpentinized lithospheric mantle may not only be an important fluid source to trigger arc melting but is also an efficient 'transport-lithology' to recycle chemically bound water into the deeper mantle. In fact, an old slab may remain sufficiently cold during subduction to retain up to 40% of its initial 'mantle' water at 8 GPa ( f 240-km depth) after serpentine transforms to higher pressure hydrous phase A.

Carbonados are aggregate polycrystalline diamonds and are found in placer deposits of the Central African Republic (CAR) and the Bahia Province of Brazil. Their origin is uncertain, but several mutually exclusive hypotheses have been proposed, ranging from extraterrestrial to crustal, and mantle provenance. In an endeavor to further our understanding of these diamonds, we performed a series of magnetic characterization studies on 20 samples from the CAR. Our results reveal that the carbonados contain material with contrasting magnetic hysteresis behavior and magnetization. Acid leaching permitted us to monitor the distribution of magnetic carriers within the samples. An absence of sample size dependence on magnetization loss indicates that the magnetic carriers are distributed at the vitreous surface; including open pores and that the carbonado interior is essentially devoid of the magnetic carriers. The diamond's isolated nonmagnetic interior of carbonados suggests that the initial formation environment was deficient in magnetic particles. The formation of the magnetic carriers is thus closely linked with the origin of the smooth surface, perhaps during the hypervelocity ejection of carbonados into the Earth's atmosphere. Partial ablation in the Earth's primordial, oxygenpoor atmosphere resulted in a fusion of the originally porous material and a decrease in the original pore density at the surface. Secondary mineralization of the impact-generated melt and/or the products of later diagenetic processes, containing the majority of the magnetic carriers, filled the remainder of the open pores. ß

and T43. In this work we present an analysis of the data observed by INMS during these encounters to derive the neutral composition of Titan's upper atmosphere between 1000 and 1100 km. Analysis methods are described for the determination and correction of instrument effects as well as the composition derivation processes. Results are compared to independent INMS analysis efforts and a selected survey of photochemical models of Titan's upper atmosphere.

This book examines Newton's argument for universal gravity and his application of it to resolve the problem of deciding between geocentric and heliocentric world systems by measuring masses of the Moon, Jupiter Planet  observed in Moroto,Uganda. Sir Isaac Newton's inferences from phenomena realize an ideal of empirical success that is richer than prediction. To achieve this rich sort of empirical success a theory needs, not only to accurately predict the phenomena it purports to explain, but also, to have those phenomena accurately measure the parameters which explain them. Newton's method aims to turn theoretical questions into ones which can be empirically answered by measurement from phenomena. Newton employs theory mediated measurements to turn data into far more informative evidence than can be achieved by confirmation from prediction alone. Propositions inferred from phenomena are provisionally accepted as guides to further research
This methodology, guided by its rich ideal of empirical success, supports a conception of scientific progress that does not require construing it as progress toward Laplace's ideal limit of a final theory of everything and is not threatened by the classic argument against convergent realism. Newton's method endorses the radical theoretical transformation from his theory to Einstein's theory of relativity. It is strikingly realized in the development and application of testing frameworks for relativistic theories of gravity. In addition, it is very much at work in cosmology today. These propositions described patterns of motion, generalised from observations of theUranus Astronomical object,Earth and moon. It has been noted by many commentators, however, that these do not seem to fit any standard definition of 'phenomenon'. 1 Some have argued that Newton's labelling was mistaken, while others have argued that Newton was using the label 'phenomenon' to avoid using the term 'hypothesis', which would mark his work as speculative, rather than experimental (for the early modern distinction between experimental and speculative philosophy.  I argue that Newton's choice of label was appropriate, albeit unconventional. Firstly, drawing on Bogen and Woodward's (1988) distinction between data, phenomena and theories, I Ariny Amos argue that Newton's phenomena performed a specific function: they isolated explanatory targets.
In experimental philosophy [science], we develop our theories from the phenomena we observe, and afterwards we develop general theories for all similar phenomena by inductive reasoning. This was how the laws of motion and gravitation of  Uranus  Astronomical object  were Original young was Observed ,discovered in Kiboga, Hoima, 6th,/Nov/2011, Mwanza Tanzania , 29/Nov/2019 Uganda, East Africa,This book comprises  Introduction , Uranus as not a Planet but An Astronomical Object, because it causes thermonuclear fusion or Volcanic eruptions, differentiate, A planet is an astronomical body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals., literature review, scope of the study, Astronomy of Uranus Astronomical Object,Experiment on formation of Uranus Mwanza Tanzania, Hoima and Kiboga Uganda.Procedure, , results, observations, discussions, recommendations, References , Further reading.

This book was written  an attempt to detect motion of the Earth through the luminiferous aether, and was conducted in( (1985-2018) by Ariny Amos), ((1901–1903) by Frederick Thomas Trouton (who also developed the Trouton's ratio) and H. R. Noble). It was based on a suggestion by George FitzGerald that a charged parallel-plate capacitor moving through the aether should orient itself perpendicular to the motion. Like the earlier Michelson–Morley experiment, Ariny Amos,Trouton and Noble obtained a null result: no motion relative to the aether could be detected.  This null result was reproduced, with increasing sensitivity, by Rudolf Tomaschek (1925, 1926), Chase (1926, 1927) and Hayden in 1994.  Such experimental results are now seen, consistent with special relativity, to reflect the validity of the principle of relativity and the absence of any absolute rest frame (or aether). See also Tests of special relativity, illustration of celestial mechanics , quantum mechanics, theory of relativity  with conspiracy theory of the new world order with an experiment,New world order conspiracy theory destructive to life on earth,The abstract for Ariny Amos experiment, F. T. Trouton and H. R. Noble experiment to detect the motion of the earth through the ether by means of electromagnetic torque on a charged, suspended, parallel-plate capacitor is reexamined illustrated in application of the new world order conspiracy theory . No previous explanation of the null result appears to be satisfactory because, as is shown herein, conventional relativistic electrodynamics predicts that the total electromagnetic field energy of the capacitor is different in the two orientations. Therefore, this combination predicts that the result should not be null. A new explanation of the null result is offered, based on a new equation for the energy density dU/dVdU/dV in the electric EE and magnetic HH fields of a classical macroscopic charged body with a uniform speed ββ in units of the speed of light. This new equation dU/dV = (E2−H2)/8π(1−β2)dU/dV = (E2−H2)/8π(1−β2), in Gaussian units in vacuo, predicts that the total electromagnetic field energy of the capacitor is independent of its orientation in agreement with the null result of Ariny Amos , Trouton and Noble experiment.
The book defines the new world order conspiracy in politics, analysis in the field, literature review,problems statement blocked by the laws of Physics which comprises Johannes laws of planetary motion, and Sir Isaac Newton’s laws of gravitation and others, scope of the study of the experiment involves uniting Physics and Astronomy, application of the experiment in New World Order Politics with characteristics of the New World Order conspiracy theory activities in the field, experiment description,apparatus , raw materials,results calculations , conclusions and recommendation,  references.

We present a study of the textural signature of terrestrial weathering and related biological activity in the Tatahouine meteorite. Scanning and transmission electron microscopy images obtained on the weathered samples of the Tatahouine meteorite and surrounding soil show two types of bacteria-like forms lying on mineral surfaces: (1) rod-shaped forms (RSF) about 70^80 nm wide and ranging from 100 nm to 600 nm in length; (2) ovoid forms (OVF) with diameters between 70 and 300 nm. They look like single cells surrounded by a cell wall. Only Na, K, C, O and N with traces of P and S are observed in the bulk of these objects. The chemical analyses and electron diffraction patterns confirm that the RSF and OVF cannot be magnetite or other iron oxides, iron hydroxides, silicates or carbonates. The sizes of the RSF and OVF are below those commonly observed for bacteria but are very similar to some bacteria-like forms described in the Martian meteorite ALH84001. All the previous observations strongly suggest that they are bacteria or their remnants. This conclusion is further supported by microbiological experiments in which pleomorphic bacteria with morphology similar to the OVF and RSF objects are obtained from biological culture of the soil surrounding the meteorite pieces. The present results show that bacteriomorphs of diameter less than 100 nm may in fact represent real bacteria or their remnants.