Comparison of the late quaternary sedimentary sequence and paleomagnetic record of the North Bay outlet and a Baffin Island fiord

The lithology of the Late Quaternary lacustrine sequences of five lakes in the North Bay area differs from one lake to another. However, chronostratigraphically equivalent sections of cores taken from the same lake do show similarities in mean grain size, sand percentage and organic and carbonate carbons.The lithology of the Late Quaternary fiord sedimentary sequence of McBeth Fiord,Baffin Island exhibits a slightly higher sand content and lower organic carbon content than the North Bay lacustrine sediments. The magnetic mineral grains deposited on the bottom of lakes and fiords tend to align in the direction of the earth's magnetic field at the time of deposition creating a remanent magnetic field in the sediments.The sedimentary sequences of lakes in the North Bay and McBeth Fiord, Baffin Island areas provides a record of the direction and intensity of the earth's magnetic field for these regions during the Late Quaternary-The declination and inclination values of oriented samples taken from soft-sediment cores of the Late Quaternary lacustrine sequences of the North Bay area and the fiord sequences of McBeth Fiord can be compiled into paleodeclination and paleoinclination logs.The oscillations of the relative paleodeclination logs show a similar character for cores taken from the five lakes and the fiord as do the paleoinclination logs.Marker horizons picked on the character of either the paleodeclination or paleoinclination logs provide a method for chronostratigraphic correlation from one core to another within the North Bay area and also for the McBeth Fiord area

Next-generation sequencing (NGS) platforms: An exciting era of genome sequence analysis

© Springer Nature Singapore Pte Ltd. 2019. DNA referred to as blueprint of life codes for the diversity and function of all the living organisms. Determining DNA sequences of the living organisms not only gives an overview of their genetic makeup, but also provides information about their function. Nonetheless it was not easy to determine the genome sequencing of all the diversity around us especially with the technologies available before 2010. Therefore, determining the sequence of humans and some other organisms only was prioritized. Pioneering methods for DNA sequencing given discovered by Maxam and Gilbert, and Sanger although were very powerful and popular but were not high throughput and economic. Therefore, it was necessary to develop new economic and high-throughput methods that can sequence the biodiversity consequently providing better insights of their possible function. New methods were developed and commercialized by Roche Life Sciences, Thermo Fisher Scientific, Illumina, and Applied Biosystems. These methods generally referred to as next-generation sequencing methods have revolutionized the DNA sequencing. Many sequencing platforms employing NGS have been developed including pyrosequencing, Ion Torrent technology, Illumina/Solexa platform, and SOLiD (Sequencing by Oligonucleotide Ligation and Detection). Further optimization has led to innovative third and fourth-generation platforms as single molecule real-time (SMRT) sequencing by PacBio, nanopore sequencing, etc. As a consequence there is a sharp increase in the number of genomes being published and other genome-based studies since 2012. This has made it easy even to imagine of sequencing the genomes of individuals. Furthermore, scientists are now looking for third-generation sequencers that may be significantly different from the sequencers that are currently available

Seasonal variation of mixed layer depth in the north Arabian Sea

The Arabian Sea is unique due to the extremes in atmospheric forcing that lead to the semi-annual seasonal changes. The reversing winds of summer and winter monsoon induce the variation in the characteristics of mixed layer depth. The importance of mixed layer depth is recognized in studying the biological productivity in the ocean. In this paper variability of mixed layer depth in the north Arabian Sea have been discussed. The study is based on the data collected under North Arabian Sea Environment and Ecosystem Research (NASEER) program. The results of the study indicate that there is a significant variation in the mixed layer depth from summer to winter monsoon as well as coast to offshore

Chemical weathering and provenance evolution of Holocene–Recent sediments from the Western Indus Shelf, Northern Arabian Sea inferred from physical and mineralogical properties

We present a multi-proxy mineral record based on X-ray diffraction and diffuse reflectance spectrophotometry analysis for two cores from the western Indus Shelf in order to reconstruct changing weathering intensities, sediment transport, and provenance variations since 13 ka. Core Indus-10 is located northwest of the Indus Canyon and exhibits fluctuations in smectite/(illite + chlorite) ratios that correlate with monsoon intensity. Higher smectite/(illite + chlorite) and lower illite crystallinity, normally associated with stronger weathering, peaked during the Early–Mid Holocene, the period of maximum summer monsoon. Hematite/goethite and magnetic susceptibility do not show clear co-variation, although they both increase at Indus-10 after 10 ka, as the monsoon weakened. At Indus-23, located on a clinoform just west of the canyon, hematite/goethite increased during a period of monsoon strengthening from 10 to 8 ka, consistent with increased seasonality and/or reworking of sediment deposited prior to or during the glacial maximum. After 2 ka terrigenous sediment accumulation rates in both cores increased together with redness and hematite/goethite, which we attribute to widespread cultivation of the floodplain triggering reworking, especially after 200 years ago. Over Holocene timescales sediment composition and mineralogy in two localities on the high-energy shelf were controlled by varying degrees of reworking, as well as climatically modulated chemical weathering

Indigenously produced biochar retains fertility in sandy soil through unique microbial diversity sustenance: a step toward the circular economy

IntroductionAgricultural productivity in the arid hot desert climate of UAE is limited by the unavailability of water, high temperature, and salt stresses. Growing enough food under abiotic stresses and decreasing reliance on imports in an era of global warming are a challenge. Biochar with high water and nutrient retention capacity and acid neutralization activity is an attractive soil conditioner. This study investigates the microbial community in the arid soil of Dubai under shade house conditions irrigated with saline water and the shift in the microbial community, following 1 year of amendment with indigenously prepared biochar from date palm waste.MethodsAmplicon sequencing was used to elucidate changes in bacterial, archaeal, and fungal community structures in response to long-term biochar amendment. Samples were collected from quinoa fields receiving standard NPK doses and from fields receiving 20 and 30 tons ha−1 of biochar, in addition to NPK for 1 year. Water holding capacity, pH, electrical conductivity, calcium, magnesium, chloride, potassium, sodium, phosphorus, total carbon, organic matter, and total nitrogen in the soil from biochar-treated and untreated controls were determined.Results and discussionThe results show that soil amendment with biochar helps retain archaeal and bacterial diversity. Analysis of differentially abundant bacterial and fungal genera indicates enrichment of plant growth-promoting microorganisms. Interestingly, many of the abundant genera are known to tolerate salt stress, and some observed genera were of marine origin. Biochar application improved the mineral status and organic matter content of the soil. Various physicochemical properties of soil receiving 30 tons ha−1 of biochar improved significantly over the control soil. This study strongly suggests that biochar helps retain soil fertility through the enrichment of plant growth-promoting microorganisms

Seismic volcanostratigraphy of the western Indian rifted margin: The pre-Deccan igneous province

The Indian Plate has been the focus of intensive research concerning the flood basalts of the Deccan Traps. Here we document a volcanostratigraphic analysis of the offshore segment of the western Indian volcanic large igneous province, between the shoreline and the first magnetic anomaly (An 28 ∼63 Ma). We have mapped the different crustal domains of the NW Indian Ocean from stretched continental crust through to oceanic crust, using seismic reflection and potential field data. Two volcanic structures, the Somnath Ridge and the Saurashtra High, are identified, extending ∼305 km NE-SW in length and 155 km NW-SE in width. These show the internal structures of buried shield volcanoes and hyaloclastic mounds, surrounded by mass-wasting deposits and volcanic sediments. The structures observed resemble seismic images from the North Atlantic and northwest Australia, as well as volcanic geometries described for Runion and Hawaii. The geometry and internal seismic facies within the volcanic basement suggest a tholeiitic composition and subaerial to shallow marine emplacement. At the scale of the western Indian Plate, the emplacement of this volcanic platform is constrained by structural lineations associated with rifting. By reviewing the volcanism in the Indian Ocean and plate reconstruction of the area, the timing of the volcanism can be associated with eruption of a pre-Deccan continental flood basalt (∼75-65.5 Ma). The volcanic platform in this study represents an addition of 19-26.5% to the known volume of the West Indian Volcanic Province. Copyright 2011 by the American Geophysical Union

Impacts of sediment supply and local tectonics on clinoform distribution: the seismic stratigraphy of the mid Pleistocene-Holocene Indus Shelf

Abstract We present results from the first high-resolution seismic reflection survey of the inner Western Indus Shelf, and Indus Delta, Arabian Sea. The results show major regional differences in sedimentation across the shelf from east to west, as well as north to south, both since the Last Glacial Maximum (*20 ka) and over longer time scales. We identify 10 major regional reflectors, interpreted as representing sea level lowstands. Strong compressive folding is observed underlying a reflector we have called Horizon 6 in the north-western shelf, probably compression associated with the transpressional deformation of the Murray Ridge plate boundary. Downslope profiles show a series of well developed clinoforms, principally at the shelf edge, indicating significant preservation of large packages of sediment during lowstands. These clinoforms have developed close to zones of deformation, suggesting that subsidence is a factor in controlling sedimentation and consequently erosion of the Indus Shelf. These clinoforms fan out from dome features (tectonic anticlines) mostly located close to the modern shoreline

Coulomb stress evolution due to coseismic, postseismic and interseismic deformation in southern California, NE Caribbean and southern Alaska

Evolution of Coulomb stress is numerically simulated in three tectonically active regions i.e., Southern California, NE Caribbean and Southern Alaska, in order to better understand the relationship between stress change and earthquake occurrence and to determine where unrelieved stress is currently the greatest. Specifically, all three major phases of the earthquake cycle i.e., interseismic deformation due to tectonic loading, coseismic slip on faults, and subsequent postseismic deformation due to viscous relaxation, are modeled over time scales of known historic seismicity, in order to: (i) estimate stresses that have accumulated on major active faults/fault segments, (ii) explain, possible triggering of historic earthquakes due to stress transfer, and earthquake sequences, and (iii) explain the observed crustal velocities (measured by GPS receivers) while decomposing them into their interseismic and postseismic (transient) components. Calculations demonstrate that large earthquakes always occur on faults that accumulate shear during the interseismic period. Coseismic slip then serves to relieve the accumulated stress on the fault but may increase it on other nearby faults/fault segments, bringing them closer to failure. Subsequent postseismic viscous relaxation serves to reload the fault and can have a large impact on deformation rates and state of stress, both in the near and far field even decades later