228 research outputs found
Guide to the geology of Bradgate Park and Swithland Wood, Charnwood Forest
Charnwood Forest is one of the few parts of England where there are exposures of ‘basement’ rocks dating back to Precambrian time. Its locally rugged topography is caused by these highly resistant rocks protruding as craggy knolls through a surrounding cover of Triassic-age Mercia Mudstone strata and Quaternary deposits. Past workers have viewed Charnwood Forest as a ‘fossil’ hill range that was carved by erosion dating from the late Carboniferous (end-Variscan) block uplifts, was subsequently buried beneath Triassic and younger strata, and is now in the process of being exhumed.
The ‘hard rock’ outcrops and distinctive scenery of Charnwood Forest, exemplified by Bradgate Park, have attracted much interest over the centuries, and Watts (1947) charts a number of publications stretching back to 1790. The lithostratigraphy of the Charnwood Forest succession was formalised after the detailed mapping and thesis of Moseley (1979), and a subsequent paper by Moseley and Ford (1985). Figure 1 shows that the Charnian Supergroup sensu stricto is divided into two principal groupings, of which the youngest, the Maplewell Group, will be visited today (localities and route are shown in Figure 2). In Swithland Wood, the strata to be visited belong to the Brand Group. This overlies the Maplewell Group, and as it is now referred to the Lower Cambrian, rather than to the Precambrian as previously thought, it is no longer included as part of the Charnian Supergroup.
A Precambrian age (i.e. older than the start of the Cambrian Period, 543 million years ago) for the Charnian rocks was hinted at as long ago as 1865. It was finally confirmed following the work of Lapworth (1882), although his observation was based on similarities between Charnian rocks and the Caldecote Volcanic Formation, which is demonstrably overlain unconformably by Lower Cambrian strata at Nuneaton, 30 km to the west. Lapworth’s discovery had major implications for something that happened much later - the finding of fossils in the Charnian strata by a schoolboy, Roger Mason, when out climbing near Woodhouse Eaves in 1957. Since then, several more fossiliferous localities have been found in Charnwood Forest (eg. Boynton and Ford, 1995), including the important exposure in Bradgate Park. Their significance to Precambrian geology, and to the understanding of the early evolution of organized life, will be discussed later on.
Much still remains to be clarified about the precise age of the Charnian Supergroup, in terms of a figure expressed in millions of years. Estimates of 560 - 566 Ma (Compston et al., 2002) have been determined for the fossil-bearing upper part of the Maplewell Group on the basis of isotopic analyses that measure the decay of uranium to lead in rock-forming minerals such as zircon. Given the exposed thickness of 3000 m for the Charnian sequence, however, it is clear that more isotopic determinations will be needed in order to constrain the entire age-range of the succession
Ghana airborne geophysics project in the Volta and Keta Basin : BGS final report
This report describes the work undertaken by BGS between November 2006 and March 2009 in
collaboration with Fugro Airborne Surveys Pty Ltd on an airborne geophysical survey and
ground reconnaissance mapping of the Volta River and Keta Basins, Ghana. The project was
supported by the EU as part of the Mining Sector Support Programme, Project Number 8ACP
GH 027/13. The initial contract duration was three years, but this was extended by five months
to account for acquisition of gravity data by another project.
Some parts of Ghana have been airborne surveyed as part of the Mining Sector Development and
Environmental Project, co-funded by the World Bank and the Nordic Development Fund, but no
work was carried out on the Volta River and Keta basins, which together form a major portion of
the Ghanaian territory.
The approximate areas covered by the surveys are estimated at 98,000 km² for the satellite
imagery and the airborne geophysics, except for the Time Domain Electromagnetic (TDEM)
survey which was limited to 60,000 km².
The main beneficiary of this project is the Geological Survey Department, GSD. The work
enhanced its geological infrastructure and its personnel received hands-on training on modern
geological mapping technology. Indirect beneficiaries were the mining and exploration
companies that can follow up the reconnaissance work with detailed exploration work.
The project was conducted in five phases, and this document reports on the BGS input to Phase
1, 4 and 5, with no inputs required in Phases 2 and 3:
• Phase1: geological outline through Radar and optical satellite imageries.
• Phase 2: airborne geophysical survey over the two basins for magnetics and
Gamma Ray spectrometry (Fugro survey).
• Phase 3: airborne electromagnetic and magnetic geophysical survey of specific
areas, following the completion and interpretation of phase 2, using fixed wing
time domain technology (Fugro survey).
• Phase 4: interpretation of the combined geology and geophysics.
• Phase 5: production of factual and interpretation maps.
The full list of BGS products is outlined in Table 1 below, while Jordan et al. (2006) describe the
products delivered on schedule in Phase 1
Provision of geological information and updating of Mineral Consultation Areas for Leicestershire County Council
This report describes work carried out by the British Geological Survey on behalf of
Leicestershire County Council to assist in the revision of their Minerals Local Plan. The work
involved the provision of maps showing the extent of individual mineral resources in the county
and the location of mineral sites where permitted reserves are present. More importantly, it also
involved updating Mineral Consultation Areas for each mineral and providing these in digital
form for use within a Geographical Information System. This report describes the methodology
adopted and presents the various results
An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics
For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types
Driver Fusions and Their Implications in the Development and Treatment of Human Cancers.
Gene fusions represent an important class of somatic alterations in cancer. We systematically investigated fusions in 9,624 tumors across 33 cancer types using multiple fusion calling tools. We identified a total of 25,664 fusions, with a 63% validation rate. Integration of gene expression, copy number, and fusion annotation data revealed that fusions involving oncogenes tend to exhibit increased expression, whereas fusions involving tumor suppressors have the opposite effect. For fusions involving kinases, we found 1,275 with an intact kinase domain, the proportion of which varied significantly across cancer types. Our study suggests that fusions drive the development of 16.5% of cancer cases and function as the sole driver in more than 1% of them. Finally, we identified druggable fusions involving genes such as TMPRSS2, RET, FGFR3, ALK, and ESR1 in 6.0% of cases, and we predicted immunogenic peptides, suggesting that fusions may provide leads for targeted drug and immune therapy
Search for Gravitational Waves Associated with Gamma-Ray Bursts Detected by Fermi and Swift during the LIGO-Virgo Run O3b
We search for gravitational-wave signals associated with gamma-ray bursts (GRBs) detected by the Fermi and Swift satellites during the second half of the third observing run of Advanced LIGO and Advanced Virgo (2019 November 1 15:00 UTC-2020 March 27 17:00 UTC). We conduct two independent searches: A generic gravitational-wave transients search to analyze 86 GRBs and an analysis to target binary mergers with at least one neutron star as short GRB progenitors for 17 events. We find no significant evidence for gravitational-wave signals associated with any of these GRBs. A weighted binomial test of the combined results finds no evidence for subthreshold gravitational-wave signals associated with this GRB ensemble either. We use several source types and signal morphologies during the searches, resulting in lower bounds on the estimated distance to each GRB. Finally, we constrain the population of low-luminosity short GRBs using results from the first to the third observing runs of Advanced LIGO and Advanced Virgo. The resulting population is in accordance with the local binary neutron star merger rate. © 2022. The Author(s). Published by the American Astronomical Society
Narrowband Searches for Continuous and Long-duration Transient Gravitational Waves from Known Pulsars in the LIGO-Virgo Third Observing Run
Isolated neutron stars that are asymmetric with respect to their spin axis are possible sources of detectable continuous gravitational waves. This paper presents a fully coherent search for such signals from eighteen pulsars in data from LIGO and Virgo's third observing run (O3). For known pulsars, efficient and sensitive matched-filter searches can be carried out if one assumes the gravitational radiation is phase-locked to the electromagnetic emission. In the search presented here, we relax this assumption and allow both the frequency and the time derivative of the frequency of the gravitational waves to vary in a small range around those inferred from electromagnetic observations. We find no evidence for continuous gravitational waves, and set upper limits on the strain amplitude for each target. These limits are more constraining for seven of the targets than the spin-down limit defined by ascribing all rotational energy loss to gravitational radiation. In an additional search, we look in O3 data for long-duration (hours-months) transient gravitational waves in the aftermath of pulsar glitches for six targets with a total of nine glitches. We report two marginal outliers from this search, but find no clear evidence for such emission either. The resulting duration-dependent strain upper limits do not surpass indirect energy constraints for any of these targets. © 2022. The Author(s). Published by the American Astronomical Society
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