Search

The utility of basic intensive care unit (ICU) training comprising a "1-day course" has been scientifically evaluated and reported in very few studies, with almost no such study from resource-limited settings.The study assessed the utility of basic ICU training comprising of a "1-day course" in increasing the knowledge of nonintensivist doctors.This is an observational study conducted at a medical university in North India in 2020. The participants were nonintensivist doctors attending the course. The course was designed by intensivists, and it had four domains. The participants were categorised on the basis of their duration of ICU experience and broad speciality. Pretest and posttest was administered, which was analysed to ascertain the gain in the knowledge score.A total of 252 participants were included, of which the majority were from the clinical medicine speciality (85.3%) and had ICU experience of 1-6 months (47.6%). There was a significant improvement in the mean total score of the participants after training from 14/25 to 19/25, with a mean difference (MD) of 5.02 (p 0.001). Based on ICU experience, in groups I (1 month), II (1-6 months), and III (6 months), there was a significant improvement in the total score of the participants after training with MD with 95% confidence interval (CI) limits of 5.27 (4.65-5.90), 4.70 (4.38-5.02), and 5.33 (4.89-5.78), respectively. In the clinical surgery specialty (n = 37), there was a significant improvement in the total score after training from 11/25 to 16.4/25 with an MD (95% CI limits) of 5.38 (4.4-6.3). Similarly, in the clinical medicine group (n = 215), the MD (95% CI limits) score after training was 4.95 (4.71-5.20), from 14.5/25 to 19.5/25. In feedback, more than half of the participants showed interest in joining ICU after training.Training nonintensivist doctors for 1 day can be useful in improving their knowledge, regardless of their prior ICU experience and speciality.

Two alternative petrogenetic models, plagioclase flotation and serial magmatism have been proposed to explain the origin of the lunar anorthositic crust, covering ~80% of the lunar highland. In this study, we re-examine the possible relict igneous texture present in an inferred lunar highland breccia clast (area ~1 mm2) in the Dhofar 081 meteorite. Our new petrographic and in-situ mineral microprobe chemical data on this clast show this coarse grained (average grain size ~0.5 mm) clast preserves relict igneous texture where subhedral, prismatic low-Ca pyroxene has intergrown with anhedral anorthitic plagioclase, suggesting its eutectic crystallization from its parent silicate magma. Absence of maskelynite and similarity of Na, K contents of plagioclase with the FAN assemblages negate the possibility of crystallization of the studied relict clast from an impact melt. The mineral-chemical data of Dhofar 081 suggest it is FAN (Ferroan anorthosite) in composition (after Warren in Annu. Rev. Earth Planet. Sci. 13:201–240, 1985). Hence, intergrown crystallization of minerals in the present relict igneous clasts and other reported FAN samples argues against a cumulate origin of the lunar anorthosite. The orthopyroxenes present in the unbrecciated portion of this meteoritic clast include bimodal low- and high-iron geochemical sub-groups. The application of orthopyroxene and plagioclase thermobarometry (after Gasparik in Contrib. Mineral. Petrol. 96:357–370, 1987) on our new microprobe data, and also two-pyroxene thermometry (after Lindsley in Am. Mineral. 68:477–493, 1983; Putirka in Rev. Mineral. Geochem. 69(1):61–120, 2008) on our new microprobe data and synthesis of literature data constrain the pressure and temperature of crystallization of lunar anorthosite parent magma close to 8 kbar and 1050°C, respectively. Application of Fo–An–Q experimental phase diagram at high pressure (up to 20 kbar) negates the possibility of generation of lunar anorthosite from a lherzolite source, the parent magma of these anorthosites probably lie on or close to Fo–An join of this phase diagram close to the spinel field.

The Ramgarh structure (rim-to-rim diameter ~2.4 km) in the Vindhyan Supergroup of sedimentary rocks (including sandstone, shale and minor limestone) of the Mesoproterozoic age in the west-central India, is India’s third confirmed asteroid impact crater. This eroded structure is roughly rectangular in shape and resembles to the Barringer Crater, USA. The presence of central peak and its current crater diameter/depth ratio of ~12 well corroborate the range (10–20) of terrestrial complex asteroid impact craters. The mm-sized, iron-rich (FeO ~50 wt.% in average), spherule-like particles, recovered from the alluvium inside the Ramgarh structure, have internal morphology similar to those of the accretionary lapilli described in known impact craters. The in-situ LA-ICP-MS analyses also suggested high Co–Ni (up to 13,000 and 2500 ppm, respectively)-rich areas locally within these spherules/lapilli. A few non-in-situ, mm-sized particles, recovered from the rim of the structure show the presence of coesite, one of the diagnostic indicators of shock metamorphism. A few fragments of iron-rich, Ca–Al–silicate glasses recovered from the soil inside the structure and outside of the western crater rim include the presence of dendritic magnetite with occasional inclusions of relict native iron. Our microprobe analyses confirm that these metallic irons contain high proportions of Co (~350–3000 ppm), Ni (~200–4000 ppm) and Cu (~2200–7000 ppm) and possibly could be the relict component of a Cu-rich iron meteorite impactor. The field observation and relative enrichment of compatible and incompatible trace elements in the spherule-like substance (recovered from the alluvium inside the Ramgarh structure) as compared to target rocks suggests that hydrothermal activity played an important role in the evolution of the crater.

The Killari Earthquake (Moment magnitude 6.1) of September 30, 1993, occurred in the state of Maharashtra, India, has an epicenter (18°03′ N, 76°33′ E) located at ~ 40 km SSW of Killari Town. The ~ 125 km long basin of Tirna River, close to the Killari Town, currently occupies the area that has witnessed episodic intra-cratonic earthquakes, including the Killari Earthquake, during last 800 years. The anisotropy of magnetic susceptibility (AMS) study was performed on ~ 233 soft sedimentary core samples from six successions located in the upper to lower stream of the Tirna River basin in the present study in order to evaluate the effects of earthquake on the river flow dynamics and its future consequence. The AMS Kmax orientations of the samples from the upper reach of the river section suggest that the sedimentation in this part of the river was controlled by a N–S to NNW–SSE fluvial regime with a low or medium flow velocity. In the middle reaches of the basin, an abrupt shift in the palaeo-flow direction occurred to W–E with low velocity flow. However, a NW–SE higher palaeo-flow regime is identified in the following central part of the basin in down-stream direction, followed by a low-velocity palaeo-flow regime at the lower reach of the Tirna basin. We attribute the sudden high flow velocity regime in the central part of the river basin to an enhanced gradient of the river that resulted from the reactivation of a NW–SE fault transecting the Tirna River basin at the Killari Town. As the NW–SE faulting in regional scale is attributed as the main cause of Killari Earthquake, the reactivation of this fault, thus, could enhance the further possibility of an earthquake in near future, and hence leading to devastating flood in the almost flat-lying downstream part of the Tirna River.

One of the major limitations in understanding the geochemical evolution of the Kaapvaal Craton, South Africa, is the scarcity of whole rock trace element data of the granitoid and other rocks compared to the vastness of this cratonic block. Here we present new XRF major oxide and ICP-MS trace element analyses of the White Mfolozi Granitoid (WMG) pluton, SE Kaapvaal Craton, which suggest that the ~ 3.25 Ga (U–Pb zircon age) old WMG pluton is a peraluminous A-type granite and could be equivalent to the intrusive potassic granite phase of the Anhalt Granitoid suite, occurring to the North of the WMG pluton. The pluton was generated by batch partial melting of a pre-existing TTG source in two major phases under relatively anhydrous conditions, and the heat of partial melting could have been provided by a voluminous mantle-derived mafic magma, which intruded into mid-crustal levels (c. 17 km), perhaps during a period of crustal extension. The estimated pressure and temperature of generation of the WMG parent magma with average molar [or/(or + ab)] ~ 0.48 could be ~ 500 MPa and close to 1000 °C, respectively, when compared with the results of experimental petrology. Interstitial occurrence of relatively iron-rich biotite [Mg/(Mg + Fe) ~ 0.41–0.45] suggests that the final temperature of crystallization of the pluton was close to 800 °C. An important magmatic event following the main phase of partial melting was limited mixing between the intrusive mafic magma and co-existing newly generated granitic melt. This magma mixing resulted in distinct variations in SiO2 and a low initial Sr isotopic ratio (0.7013) of the WMG pluton. Although both the models of partial melting of quartzo-feldspathic sources and fractional crystallization of basaltic magmas with or without crustal assimilation have been proposed for the origin of A-type granites, the model of magmatic evolution of the WMG pluton presented here can also be an alternative model for the generation of A-type granites. In this model, post-partial melting magma mixing is perhaps critical in explaining the Daly gap in composition and extreme variations in chemical (e.g., SiO2) and isotopic compositions observed in many bimodal A-type granite suites. The emplacement of the oldest known A-type granitoid suite in the Kaapvaal Craton, the WMG pluton, marks a period of stabilization of the craton before erosion and deposition of the overlying volcano-sedimentary succession of the Pongola Supergroup.

The Lonar impact crater, India, is one of the few known terrestrial impact craters excavated in continental basaltic target rocks (Deccan Traps, ~65 Ma). The impactites reported from the crater to date mainly include centimeter- to decimeter-sized impact-melt bombs, and aerodynamically shaped millimeter- and submillimeter-sized impact spherules. They occur in situ within the ejecta around the crater rim and show schlieren structure. In contrast, non–in situ glassy objects, loosely strewn around the crater lake and in the ejecta around the crater rim do not show any schlieren structure. These non–in situ fragments appear to be similar to ancient bricks from the Daityasudan temple in the Lonar village. Synthesis of existing and new major and trace element data on the Lonar impact spherules show that (1) the target Lonar basalts incorporated into the spherules had undergone minimal preimpact alteration. Also, the paleosol layer as preserved between the top-most target basalt flow and the ejecta blanket, even after the impact, was not a source component for the Lonar impactites, (2) the Archean basement below the Deccan traps were unlikely to have contributed material to the impactite parental melts, and (3) the impactor asteroid components (Cr, Co, Ni) were concentrated only within the submillimeter-sized spherules. Two component mixing calculations using major oxides and Cr, Co, and Ni suggest that the Lonar impactor was a EH-type chondrite with the submillimeter-sized spherules containing ~6 wt% impactor components.

The Ramgarh structure of SE Rajasthan, central India, situated within an almost undeformed, flat-lying Vindhyan Supergroup of sedimentary rocks of Meso- to Neoproterozoic age, is a potential candidate of asteroid impact crater for last many decades. A fresh observation on remote sensing images (ASTER, Landsat and Google Earth Imageries) along with structural analyses in field show that this rectangular structure has a rim-to rim diameter of ~

Extant peritidal, micritic stromatolites and tufa are growing discontinuously along the southeast African Indian Ocean rocky peritidal zone. Microbialites are ubiquitous on this coast but only calcify when carbonate rich groundwater is present; if horizontal surfaces (shore platforms) are present stromatolites develop, if vertical surfaces are present tufa forms. Tufa and stromatolites are end members of a spectrum dictated by coastal topography. Extant shore-platform stromatolites (SPS) occur in very high wave energy settings, often around headlands, boulder beaches and/or beach ridges, storm swash-terraces and coastal dunes. Stromatolite growth is seen on soft coastlines but the preservation potential is very low/ zero. SPS are produced by mineral precipitation, not trapping and binding. SPS are developing in a mildly transgressive siliciclastic setting. Laminar and colloform stromatolite morphologies could be preserved in the geological record as micritic lenses on a palaeo-shore platform surface. SPS share many features with Precambrian stromatolites. Terraces associated with oceanic or lacustrine flooding surfaces should not be ignored when searching for potential stromatolite deposits on Mars.

The ~50 or 570 ka old Lonar crater, India, was excavated in the Deccan Trap flood basalt of Cretaceous age by the impact of a chondritic asteroid. The impact-spherules known from within the ejecta around this crater are of three types namely aerodynamically shaped sub-mm and mm size spherules, and a sub-mm sized variety of spherule, described as mantled lapilli, having a core consisting of ash-sized grains, shocked basalt and solidified melts surrounded by a rim of ash-sized materials. Although, information is now available on the bulk composition of the sub-mm sized spherules (Misra et al. in Meteorit Planet Sci 7:1001–1018, 2009), almost no idea exists on the latter two varieties. Here, we presented the microprobe data on major oxides and a few trace elements (e.g. Cr, Ni, Cu, Zn) of mm-sized impact spherules in unravelling their petrogenetic evolution. The mm-sized spherules are characterised by homogeneous glassy interior with vesicular margin in contrast to an overall smooth and glassy-texture of the sub-mm sized spherules. Undigested micro-xenocrysts of mainly plagioclase, magnetite and rare clinopyroxene of the target basalt are present only at the marginal parts of the mm-sized spherules. The minor relative enrichment of SiO2 (~3.5 wt% in average) and absence of schlieren structure in these spherules suggest relatively high viscosity of the parent melt droplets of these spherules in comparison to their sub-mm sized counterpart. Chemically homogeneous mm-sized spherule and impact-melt bomb share similar bulk chemical and trace element compositions and show no enrichment in impactor components. The general depletion of Na2O within all the Lonar impactites was resulted due to impact-induced volatilisation effect, and it indicates the solidification temperature of the Lonar impactites close to 1,100 °C. The systematic geochemical variation within the mm-sized spherules (Mg# ~0.38–0.43) could be attributed to various level of mixing between plagioclase-dominated impact melts and ultrafine pyroxene and/or titanomagnetite produced from the target basalt due to impact. Predominance of schlieren and impactor components (mainly Cr, Ni), and nearly absence of vesicles in the sub-mm sized spherules plausibly suggest that these quenched liquid droplets could have produced from the impactor-rich, hotter (~1,100 °C or more) central part of the plume, whereas the morpho-chemistry of the mm-sized spherules induces their formation from the relatively cool outer part of the same impact plume.

CONTEXT: Various adjuvants such as opioids or α2 agonists are being used to improve the quality and duration of caudal analgesia with local anesthetics. Dexmedetomidine a α2 agonist is used frequently in adult patients to enhance the local anesthetic effect. However there is little literature regarding its effectiveness in pediatric caudal analgesia. The objective of this study was to assess the efficacy of dexmedetomidine when used as an adjuvant to bupivacaine in increasing the duration of caudal analgesia. AIM: The aim of this study was to investigate the effect of adding Dexmedetomidine to caudal Bupivacaine and observe the effect on the duration of analgesia in the post-operative period. SETTINGS AND DESIGN: One year hospital based Double Blind Randomized Controlled Trial. METHODS AND MATERIAL: Sixty children, aged 1-6 years, undergoing lower abdominal surgeries were included in this prospective randomized double-blind study. The patients were randomly divided into two groups: Group I received Bupivacaine (0.25%) 1ml/kg plus 1 ml of normal saline in the caudal epidural space. Group II was administered Bupivacaine (0.25%) 1ml/ with Dexmedetomidine 2 mcg/ ml diluted to 1 ml of normal saline in the caudal epidural space. All anesthetic and surgical techniques were standardized. Heart rate, blood pressure, oxygen saturation, respiratory rate were monitored continuously. Surgery was started 10-15 minutes after the injection and confirming adequacy of caudal block. Duration of analgesia was assessed using FLACC scale (Face, Legs, Activity, Cry, Consolability scale). The time from administration of caudal anesthesia to the first time the FLACC score equal or greater than 4 was considered as the duration of caudal analgesia. Paracetamol suppository was used as rescue analgesia with a loading dose of 40mg/kg. STATISTICAL ANALYSIS: Mann-Whitney test and Student 't'test was used to compare the data obtained in the two groups. RESULTS: The demographic parameters, duration of surgery and the types of surgery were comparable in the two groups. The mean duration of analgesia was261.33 ± 31.04 min in Group I compared to 532.67 ± 47.12 min in Group II. Hence the duration of analgesia was found significantly prolonged in Group II than in Group I with p value

A comparison of geochemical and Sr-Nd-Pb isotopic compositions for Deccan Continental Flood Basalts (CFBs) and Central Indian Ridge (CIR) basalts is presented: these data permit assessment of possible parental linkages between the two regions, and comparison of their respective magmatic evolutionary trends in relation to rift-related tectonic events during Gondwana break-up. The present study reveals that Mid-Ocean Ridge Basalt (MORB) from the northern CIR and basalts of Deccan CFB are geochemically dissimilar because of: (1) the Deccan CFB basalts typically show a greater iron-enrichment as compared to the northern CIR MORB, (2) a multi-element spiderdiagram reveals that the Deccan CFBs reveal a more fractionated slope (Ba/YbN>1), as compared to relatively flat northern CIR MORB (Ba/YbN

Geophysical techniques based on radioactivity measurements are not generally used for exploration of asteroid impact craters. Our studies on the field and laboratory measurements of radioactivity on samples from the Lonar crater, India, show that this technique could be an important method for mapping the distribution of ejecta around the deeply excavated impact craters particularly when these structures are formed on relatively old target rocks/palaeosol. The Lonar ejecta shows ~1.3 times higher γ-ray count rates in the field on average compared to the underlying palaeosol and ~1.9 times higher values over the target basalt while measured by a portable Geiger–Muller pulse counter. The absorbed γ-dose rate (D) of the Lonar samples, computed from 232Th, 238U, and 40K abundances in these samples, also show that the ejecta has distinct bulk dose rates (average ~8.42 nGy h−1) as compared to those of the palaeosol (~18.34 nGy h−1), target basalt (~11.97 nGy h−1), and the impact-melts and spherules (~14 nGy h−1). Therefore, radioactivity mapping of the terrestrial and planetary impact craters by direct methods has importance in mapping ejecta distributions around these structures.

We present new major and ICP-MS trace element data of the Carlsberg Ridge MORBs from two different locations (i.e., 3°35 / N/64°05 / E and 3°41 / N/64°09 / E) and reassess the intra-ridge geochemical variations of Carlsberg Ridge- Central Indian Ridge MORBs in the present work. Geochemically, the trace element contents of the Carlsberg Ridge MORBs are similar to the Rodriguez Triple Junction MORBs [e.g., LIL and REE spidergrams and (La/Sm)N ratio etc.] and both are closely resembling to the average N-MORB in composition. The MORBs from the northern- and southern Central Indian Ridge, however, significantly vary in composition between average N- and E-MORBs. The Carlsberg Ridge- Central Indian Ridge MORBs, in general, show much less fractionation in FeOt in MgO-CaO-FeOt diagram compared to those of the Mid Atlanticand East Pacific Rise MORBs. Further, the depleted LREE and nearly flat HREE patterns of the Carlsberg Ridge- Central Indian Ridge MORBs, along with their least variability of compatible trace element (Ni, Cr, Sr) contents against increasing incompatible trace element (Y, Zr) contents in the log-log plots and their increasing incompatible trace element ratios in the process identification plots favor partial melting dominated process for their petrogenetic evolution. Our review on isotope data (Sr, Nd, Pb) shows that the Carlsberg Ridge-Central Indian Ridge MORBs were derived from a depleted mantle source that was variously contaminated by continental crust perhaps during the third stage of Gondwana break up between 155-135 Ma or later due to the strike slip movement along a mega fracture, a member of the Davie Transform Faults in the Somali Basin, that broke the Gondwanaland into the East and West Gondwanas and during subsequent movement of these two blocks away from each other. The 208 Pb/ 204 Pb versus 206 Pb/ 204 Pb plot of above mentioned MORBs suggests that the depleted mantle source of the Rodriguez Triple Junction MORBs was contaminated by ~21% lower continental crust, whereas the mantle source of the Central Indian Ridge MORBs was contaminated by upper continental crust, which are ~19% for the Carlsberg Ridge and Northern Central Indian Ridge MORBs and ~32% for the Southern Central Indian Ridge MORBs. The contaminated mantle sources were compositionally similar to the Al-depleted Komatiite basalt in composition and significantly enriched in Rb, Ba, La and Ce over the depleted mantle.

Gabbro samples (c. < 0.4 Ma old) dredged from close to the ‘Vityaz Megamullion’ on the slow-spreading Northern Central Indian Ridge (NCIR, 18–22 mm yr−1) include mostly olivine gabbro and Fe–Ti oxide gabbro. The cumulate olivine gabbro shows ophitic to subophitic texture with early formed plagioclase crystals in mutual contact with each other, and a narrow range of compositions of olivine (Fo80–81), clinopyroxene (magnesium number: 85–87) and plagioclase (An67–70). This olivine gabbro could be geochemically cogenetic with the evolved oxide gabbro. These gabbro samples are geochemically distinct from the CIR gabbro occurring along the Vema, Argo and Marie Celeste transform faults and can further be discriminated from the associated NCIR basalts by their clinopyroxene (augite in gabbro, and diopsidic in basalts) and olivine (gabbro: Fo80–81, basalts: Fo82–88) compositions. Our major oxide, trace element and REE geochemistry analyses suggest that the gabbro and the NCIR basalts are also not cogenetic and had experienced different trends of geochemical evolution. The clinopyroxenes of the present NCIR gabbros are geochemically similar to primitive melt that is in equilibrium with mantle peridotite, and do not show any poikilitic texture with resorbed plagioclase; these results negate the possibility of these gabbros being a pre-existing cumulate that has been brought up to the shallower oceanic crust and interacted with the NCIR basalt. The Sr, Pb and Nd isotopic data of the gabbro substantially differ from those of the NCIR basalts and suggest significant contamination of the depleted mantle source of the gabbro, most likely by the Indian Ocean pelagic sediments. The Pb-isotope data suggest that the proportion of pelagic sediment that mixed in the depleted mantle source of the NCIR gabbro is much higher than the level of contamination observed for the Indian Ocean MORBs.

The anisotropy of magnetic susceptibility (AMS) technique, combined with the analyses of satellite images and the geological structure, are examined on Lonar crater, a small, ∼1.8-km-diameter impact crater in India, to evaluate the direction and obliquity of asteroid impact. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) image (15-m resolution) of the ca. 52 ka Lonar crater in the subhorizontal Deccan basalt (ca. 65 Ma) shows that this simple, bowl-shaped impact crater has a near-circular rim with a circularity of ∼0.95. Most of the highly reflecting, continuous-ejecta blanket around the crater rim can be enveloped with an ellipse whose major E-W axis is coincident with the diameter of the crater rim and minor N-S axis is relatively displaced toward the west by ∼200 m. The present ejecta distribution, which appears to be close to its pristine shape, extends to a distance of ∼700 m in all the directions from the crater rim except to the west where it extends to a distance of a little more than 1 km. The circular shape of the crater rim, the E-W bilateral symmetry of the enveloping ellipse on the ejecta, and the greater extension of the ejecta toward the west appear to be the result of an oblique impact from the east with an angle of incidence of 30°–45° when compared with experiments. The AMS data suggest that the target basalts occurring at ∼2 km west-southwest of the crater rim are highly shocked, as indicated by the random orientation of their K 3 susceptibility axes in comparison to the unshocked basalts at ∼2 km east-southeast of the crater; the unshocked basalts show a bimodal distribution of susceptibility axes typical of lava flows. Moderate to strong westward shifts of the K 3 axes are seen for the majority of the shocked basalts on the crater rim and west-southwest of the crater; the shocked basalts also indicate an oblique impact from the east when compared with modeling and experiments. A general lowering of degree of anisotropy of the Lonar shocked basalts (∼1.01) compared to the surrounding unshocked basalts (∼1.03) is found to be a characteristic feature of impact crater target rocks. Variation in attitudes of the basalt flows on the Lonar crater rim shows a bilaterally symmetrical distribution about an E-W axial plane, which includes quaquaversal dips of the flows all around the crater rim, except to the west where overturned dips of the basalt flows are seen. It appears that oblique impact and the symmetry in structural variations around the crater rim have a relationship for a small crater such as Lonar.

This paper intends to explore whether there is an important source for monazite beach placer of the Gopalpur-Chhatrapur-Rushikulya coast, Orissa, in the adjacent Eastern Ghat Mobile Belt (EGMB). Petrographic and mineralogical studies were conducted on all the rock types constituting the EGMB exposed over a stretch extended up to ∼20 km landward from the estuary of the River Rushikulya that is believed to transport the major bulk of sand to the Gopalpur-Chhatrapur-Rushikulya beach. Heavy mineral population was concentrated using bromoform and percentages of each heavy mineral constituting the population were estimated for all the potential source rock types. Isodynamic separation and XRD techniques were deployed for precision identification of every heavy mineral present. The study identified the granitoid (or migmatite) basement rock as by far the major contributor of monazite to the Chhatrapur beach sand. The study also reveals that charnockite is an important contributor of orthopyroxene as well as garnet, although the sillimanite-garnet-quartz schist (khondalites) is also an important source for the latter. On the other hand, garnet-quartz schist and garnet-biotite-quartz schist may also contribute substantial quantity of pyroxene and garnet. The high grade metasedimentary rocks, in general, could be the major sources for rutile, while ilmenite, magnetite and zircon in the beach sand have their sources perhaps in all the varieties of rocks constituting the EGMB.

The only well-known terrestrial analogue of impact craters in basaltic crusts of the rocky planets is the Lonar crater, India. For the first time, evidence of the impactor that formed the crater has been identified within the impact spherules, which are ~0.3 to 1 mm in size and of different aerodynamic shapes including spheres, teardrops, cylinders, dumbbells and spindles. They were found in ejecta on the rim of the crater. The spherules have high magnetic susceptibility (from 0.31 to 0.02 SI-mass) and natural remanent magnetization (NRM) intensity. Both NRM and saturation isothermal remanent magnetization (SIRM) intensity are ~2 Am2/kg. Demagnetization response by the NRM suggests a complicated history of remanence acquisition. The spherules show schlieren structure described by chains of tiny dendritic and octahedral-shaped magnetite crystals indicating their quenching from liquid droplets. Microprobe analyses show that, relative to the target basalt compositions, the spherules have relatively high average Fe2O3 (by ~1.5 wt%), MgO (~1 wt%), Mn (~200 ppm), Cr (~200 ppm), Co (~50 ppm), Ni (~1000 ppm) and Zn (~70 ppm), and low Na2O (~1 wt%) and P2O5 (~0.2 wt%). Very high Ni contents, up to 14 times the average content of Lonar basalt, require the presence of a meteoritic component in these spherules. We interpret the high Ni, Cr, and Co abundances in these spherules to indicate that the impactor of the Lonar crater was a chondrite, which is present in abundances of 12 to 20 percent by weight in these impact spherules. Relatively high Zn yet low Na2O and P2O5 contents of these spherules indicate exchange of volatiles between the quenching spherule droplets and the impact plume.

During the Pliocene–Pleistocene epoch, covering last ∼5.2 Ma of Earth’s history, altogether 34 terrestrial meteoritic impact craters are known. Most of these craters (29) have diameter ≤10 km, among which 11 craters fall in 1,000 to 100 m range, and 7 are still smaller in dimension and of recent age. The age versus impact-frequency plot shows that the meteoritic impacts during this time period occurred in discrete intervals but have a periodicity that shows the best possible coincidence with the ∼425 Ky climatic cycles observed by Fourier analysis and FFT filtering of composite high resolution benthic foraminiferal δ18O record. This observation is also supported by Monte Carlo test with 71% success where meteoritic impact(s) shows coincidence with climatic cooling within our error limit. The newly observed climatic–meteoritic cycle may be same with the ∼400 Ky Milankovitch cycle or it is a different newly understood cycle relating both the climatic variation and meteoritic impact events.

The Lonar crater, India, is the only well-preserved simple crater on Earth in continental flood basalts; it is excavated in the Deccan trap basalts of Cretaceous-Tertiary age. A representative set of target basalts, including the basalt flows excavated by the crater, and a variety of impact breccias and impact glasses, were analyzed for their major and trace element compositions. Impact glasses and breccias were found inside and outside the crater rim in a variety of morphological forms and shapes. Comparable geochemical patterns of immobile elements (e.g., REEs) for glass, melt rock and basalt indicates minimal fractionation between the target rocks and the impactites. We found only little indication of post-impact hydrothermal alteration in terms of volatile trace element changes. No clear indication of an extraterrestrial component was found in any of our breccias and impact glasses, indicating either a low level of contamination, or a non-chondritic or otherwise iridium-poor impactor.

The Singhbhum Mobile Belt (SMB) of the eastern Indian shield represents a roughly east-west-trending arcuate belt of folded supracrustals overlying the granite-greenstone basement of the Singhbhum-Orissa Craton along its northern, eastern and western margins and is bounded by the Chotanagpur Gneissic Complex to further north. The radiometric ages of the basement Singhbhum and equivalent granites and the intrusive anorogenic Mayurbhanj granite pluton constrain the time of evolution of this mobile belt between ∼3.12 and 3.09 Ga. Hence, the SMB supracrustals also known as Singhbhum Group, is late Mesoarchaean in age and not Proterozoic as thought earlier. The evolution of the SMB was followed by emplacement of some major basic igneous rocks within or adjacent to the supracrustals. These include Simlipal volcanics at ∼>3.09 Ga on the SMB, Mayurbhanj gabbro along with Mayurbhanj granite at ∼3.09 Ga along the marginal part of the craton near the SMB, and the Dalma volcanics on the SMB along with the Dhanjori volcanics adjacent to SMB at ∼2.80 Ga. The ∼ 2.80 Ga old basic volcanics is also associated with emplacement of some small granite plutons occurring along the marginal part of the craton, one of them, the Tamperkola granite intrudes the SMB. The ∼>3.09 Ga onward igneous activities along the marginal part of Singhbhum-Orissa Craton took place essentially under anorogenic tectonic setting before being affected by a major metamorphism at ∼2.50 Ga, which is recorded on the Dalma volcanics and on some small granite pluton occurs along the marginal part of the craton. The Jagannathpur and stratigraphically equivalent Malangtoli volcanics, occurring within the Singhbhum-Orissa Craton at the west, were erupted at ∼2.25 Ga. The boundary between the SMB supracrustals and the Singhbhum-Orissa Craton is demarked by a prominent shear zone known as the Singhbhum Shear Zone, which shows multiple reactivation, the oldest being at ∼3.09 Ga, followed by subsequent reactivation during Palaeo- and Mesoproterozoic periods at ∼2.2, 1.8, 1.6-1.5, 1.4 and 1.0 Ga respectively. The Singhbhum Group and the adjacent Chotanagpur Gneissic Complex appear to have evolved from a near shore syn-rift and a distal post-rift stable shelf sedimentary assemblages respectively, which were deposited without any stratigraphic break in a marine basin existed in the present north of the Singhbhum-Orissa Craton. Both of these assemblages were deformed and metamorphosed together during Proterozoic at ∼2.5 to >2.3 Ga, ∼1.6 Ga and ∼1.0 Ga.

The A-type Mayurbhanj Granite Pluton (∼3.09 Ga), occurring along the eastern margin of the Singhbhum-Orissa Craton, eastern India, represents the final phase of acid plutonism in this crustal block of Archean age. The granite shows a bimodal association with a voluminous gabbroid body, exposed mainly along its western margin, and is associated with the Singhbhum Shear zone. The granite pluton is composed mainly of a coarse ferrohastingsite–biotite granite phase, with an early fine-grained granophyric microgranitic phase and a late biotite aplogranitic phase. Petrogenetic models of partial melting, fractional crystallisation and magma mixing have been advocated for the evolution of this pluton. New data, combined with earlier information, suggest that two igneous processes were responsible for the evolution of the Mayurbhanj Granite Pluton: partial melting of the Singhbhum Granite; followed by limited amount of mixing of acid and basic magmas in an anorogenic extensional setting. The necessary heat for partial melting was provided by the voluminous basaltic magma, now represented by the gabbroid body, emplaced at a shallow crustal level and showing a bimodal association with the Mayurbhanj Granite Pluton. The Singhbhum Shear Zone provided a possible channel way for the emplacement of the basic magma during crustal extension. It is concluded that all three phases of the Mayurbhanj Granite Pluton were derived from the same parent magma, generated by batch partial melting of the Singhbhum Granite at relatively high temperatures (∼980 °C) and low pressures (4 to

The Tamperkola granite-acid volcanics association occurring at the western margin of the Archaean Singhbhum-Orissa Iron Ore Craton (SOC), eastern India, is intrusive into the Darjing Group which represents a sequence of mobile belt metasediments in this part of the SOC. The Darjing Group rests unconformably on the Bonai Granite (∼3.2 Ga old). Absence of any deformational imprints of the country rock metasediments on the Tamperkola granite acid volcanics together with its undeformed and unmetamorphosed nature, its alkali feldspar dominant mineralogy, and its high SiO 2 and Na 2 O + K 2 O and low MgO and CaO contents suggest that this granite-acid volcanics association is anorogenic in nature. Two representative samples-one each from the granite and the acid volcanics have been dated by in situ 207 Pb/ 206 Pb zircon dating method using a small ion-microprobe. Minimum age of crystallisation of the acid volcanics is found to be 2.8 Ga. Strong peak in the 207 Pb/ 206 Pb frequency diagram and equality of the observed and expected errors in radiogenic 207 Pb/ 206 Pb ratios suggest that this age probably represents the true age of formation of the volcanics. The age data place the deposition and metamorphism of the mobile belt metasediments of the Darjing Group in between 3.2 and 2.8 Ga. Occurrence of 2.9–2.8 Ga old small granitoid plutons, alkali-feldspar granite to syenogranite in composition, is also known from the southern margin of the SOC. Therefore, it appears that around 2.9–2.8 Ga small alkali granite bodies formed at the marginal part of this cratonic block after its stabilisation at ∼3.1 Ga.

The small granite plutons occurring at the contact of the Singhbhum-Orissa Iron Ore craton (IOC) to the north and the Eastern Ghat Granulite Belt (EGGB) to the south in eastern Indian shield are characterised by the presence of enclaves of the granulites of EGGB and the greenschist facies rocks of IOC. These granites also bear the imprints of later cataclastic deformation which is present at the contact of the IOC and the EGGB. In situ Pb-Pb zircon dating of these granites gives minimum age of their formation ∼2.80 Ga. A whole-rock three point Rb-Sr isochron age of this rock is found to be ∼2.90 Ga. Therefore, the true age of formation of these granites will be around 2.90–2.80 Ga. These granitic rocks also contain xenocrystic zircon components of ∼3.50 Ga and show a later metasomatic or metamorphic effect ∼ 2.48 Ga obtained from the analyses on overgrowths developed on 2.80 Ga old zircon cores. The presence of granulitic enclaves within these contact zone granite indicates that the granulite facies metamorphism of the EGGB is ∼2.80 Ga or still older in age. The cataclastic deformations observed at the contact zone of the two adjacent cratons is definitely younger than 2.80 Ga and possibly related to 2.48 Ga event observed from the overgrowths. As 2.80 Ga granite plutons of small dimensions are also observed at the western margin of the IOC; it can be concluded that a geologic event occurred ∼2.80 Ga over the IOC when small granite bodies evolved at the marginal part of this craton after its stabilisation at ∼ 3.09 Ga.

[1] The Pliocene-Pleistocene Karewa Group sediments of the Kashmir basin, India, provide an important continental archive for past climatic reconstruction. The present study reevaluates the magnetic polarity stratigraphy and the nature of the depositional environment at a 440-m-thick section along Romushi river near Pakharpur (33°48′50″N, 74°45′54″E). Magnetic remanences are predominantly carried by Ti-rich titanomagnetite and magnetite. We identified eight normal and eight reversed-polarity magnetozones in this succession, ranging between 4.40 and 0.77 Ma. The polarity sequence includes the new identification of the Cochiti and the Mammoth and their preceding and succeeding reversed/normal as well as the Jaramillo subchrons. Anisotropy of magnetic susceptibility data suggest the existence of northeast- and northwest-flowing fluvial system before 4.18 Ma, indicating the Pir Panjal range at the southwest as the sediment source area. Following this, the valley was under the influence of fluviolacustrine environment between 4.18 and 0.77 Ma. Our results suggest relatively strong flow velocity toward the northeast during the upper Gilbert, Gauss, and lower and middle Matuyama chrons (4.18–1.07 Ma). In the upper Matuyama chron (

Thrombocytopenia is a common manifestation in pregnancy. It is mostly dilutional when no pathological causation is evident. There are no clear-cut guidelines to determine the platelet count at which anesthesiologists can safely administer regional anesthesia in obstetric patients. A safe approach in an asymptomatic mother is outlined here.

The Eastern Ghats granulite belt of India has traditionally been described as a Proterozoic mobile belt, with probable Archaean protoliths. However, recent findings suggest that synkinematic development of granulites took place in a compressional tectonic regime and that granulite facies metamorphism resulted from crustal thickening. The field, petrological and geochemical studies of a charnockite massif of tonalitic to trondhjemitic composition, and associated rocks, document granulite facies metamorphism and dehydration partial melting of basic rocks at lower crustal depths, with garnet granulite residues exposed as cognate xenoliths within the charnockite massif. The melting and generation of the charnockite suite under granulite facies conditions have been dated c. 3.0 Ga by Sm–Nd and Rb–Sr whole rock systematics and Pb–Pb zircon dating. Sm–Nd model dates between 3.4 and 3.5 Ga and negative epsilon values provide evidence of early Archaean continental crust in this high-grade terrain.