Groundwater arsenic (As) presents a public health risk of great magnitude in densely populated Asian delta regions, most acutely in the Bengal Basin (West Bengal, India and Bangladesh). Research has focussed on the sources, mobilization, and heterogeneity of groundwater As, but a consistent explanation of As distribution from local to basin scale remains elusive. We show for the Bengal Aquifer ...

In the Bengal Basin, the land surface exposed during the last lowstand of sea-level around 20 ka, and now buried by Holocene sediment, is capped by an impermeable clay palaeosol that we term the Last Glacial Maximum Palaeosol (LGMP). The palaeosol strongly affects groundwater flow and controls the location of arsenic pollution in the shallow aquifers of our study site in southern West Bengal an...

The integration of sedimentological and structural data in the western end of the Ripoll syncline allows a clearer understanding of the palaeogeography of the area between the oblique termination of the Pedraforca thrust sheet and the frontal Vallfogona thrust during middle Eocene times. In this region, a 2.5-km thick clastic succession corresponding to the Bellmunt and Milany sequences infille...

U–Pb ages of individual detrital zircon grains from deltaic and turbidite sandstones of the lower to middle Pennsylvanian Haymond Formation (Marathon basin, west Texas) range from 320 Ma to 3 Ga, indicating a mixed provenance broadly similar to that of Ouachita Carboniferous turbidites and related fluvio-deltaic facies of Arkansas–Oklahoma. Differences with the Ouachita assemblage are attribute...

Morrowan-age units in the Permian Basin appear to show a “second-order” transgression from siliciclastic fluvial-deltaic to shallow-marine and subsequently to carbonate deposition. In general, Morrowan-age siliciclastics dominate deposition in the west of the Permian Basin, while carbonate deposition dominates in the east. The predominance of carbonate facies in the east is due to a lack of sil...

Natural pollution of groundwater by arsenic adversely affects the health of tens of millions of people worldwide, with the deltaic aquifers of SE Asia being particularly polluted. The pollution is caused primarily by, or as a side reaction of, the microbial reduction of sedimentary Fe(III)-oxyhydroxides, but the organism(s) responsible for As release have not been isolated. Here we report the f...

Detailed log facies studies of Miocene succession in the well Rashidpur-04, Rashidpur structure, Surma Basin were carried out by integrating wireline log and limited core sample data in order to reconstruct the paleoenvironments of deposition. Based on the analysis of the log motifs, grain size, sand/shale ratio and major change in gamma ray log motifs, two major depositional sequences were ide...

The presence of valley networks and open-basin lakes in the late Noachian is cited as evidence for overland flow of liquid water and thus a climate on early Mars that might have supported precipitation and runoff. Outstanding questions center on the nature of such a climate, its duration and variability, and its cause. Open basin lakes, their interior morphology, and their associated channels p...

Neogene sedimentary rocks are exposed in the Chittagong Tripura Folded Belt (CTFB) Region Bengal Basin. Sitapahar anticline is situated middle part of CTFB Region. In this structure, eleven litho-facies have been identified fluvial, overbank, shallow marine, deltaic, and deep marine depositional environments. Surma Group composed Bhuban Boka Bil formation during Miocene time was deposited envir...

Middle Jurassic fluvio-deltaic and turbiditic mudstones of the Kashafrud Formation, are important hydrocarbon sources in the gas-rich Kopet-Dagh Basin, northeast Iran. Clay mineral assemblages are important for interpretation of sediment provenance and for understanding burial diagenetic cementation in sandstones. The clay mineral assemblages in mudrocks in two areas, Saleh-Abad and Senjedak, w...