This layer of the map based index (GeoIndex) providex an index to 17,500 borehole rock samples (drillcore) from the Mineral Reconnaissance Programme (MRP) and related studies. The UK Government's Department of Trade and Industry (DTI) funded BGS to provide baseline information on areas prospective for the occurrence of metallic minerals in Great Britain. This programme, known as the MRP, ran continuously from 1973 to 1997 and covered particular locations across Great Britain. It was designed to stimulate private sector exploration and to encourage the development of Britain's indigenous mineral resources. Under the programme a number of boreholes were drilled to gather information.
The map shows the localities where samples that form part of the BGS rock collections have been taken. Many of these samples are from surface exposure, and were collected by BGS geologists during the course of geological mapping programmes. Others are from onshore boreholes or from mine and quarry workings. The principal collections are the E (England and Wales), S (Scotland), N (continuation of the S collection) and the MR (miscellaneous). The collections, which are held at the BGS offices at Keyworth (Nottingham) and Edinburgh, comprise both hand specimens and thin sections, although in individual samples either may not be immediately available. Users may also note that the BGS holds major collections of borehole cores and hand specimens as well as over a million palaeontological samples. The Britrocks database provides an index to these collections. With over 120,000 records, it now holds data for some 70% of the entire collections, including the UK samples shown in this application as well as rocks from overseas locations and reference minerals. The collections are continuously being added to and sample records from archived registers are also being copied into the electronic database. Map coverage is thin in some areas where copying from original paper registers has not been completed. Further information on Britrocks samples in these and other areas can be obtained from the Chief Curator at the BGS Keyworth (Nottingham) office or from the rock curator at the BGS Murchison House (Edinburgh) office.
This low-resolution image has been produced from BGS land and marine gravity data. The colour was generated using the BGS COLMAP software package. Colour levels are defined by histogram equalisation. Combining this image with the grey shaded relief image produces a similar image to the colour shaded relief image. The measured gravity values have been corrected in order to show the anomalies attributable to variations in crustal density. In broad terms the blues are attributable to large volumes of low density rocks, the reds to high density rocks. Significant lows occur, for instance, over areas of thick, low density sedimentary rocks(e.g. Cheshire Basin, Wessex Basin), or large granites (eg Cornwall). For marine data, free-air anomalies have been calculated from observed gravity values along marine survey lines. Line intersection errors between crossing lines and overlapping surveys have been used using network adjustment techniques. Free air anomalies have been calculated for sea-bottom stations. For land data, bouguer anomalies have been calculated from gravity observations at points of known height. In order to minimise the effect of topography, Bouguer corrections for the British Mainland have been applied using a density estimated for each station. Elsewhere a correction density of 2.67 Mg/m3 has been used. Corrections for the gravitational effect of terrain have been made where significant, and in a general extent to a radius of 48.6km. The data have been interpolated onto a 1km x 1km grid using a variable tension technique, and smoothed.
The data set consists of the results of particle size analysis (PSA) performed on approximetaly 29,000 sea-bed sediment samples collected by BGS from the UK Continental Shelf and adjacent deep water areas, mostly using sediment grabs, but also sediment corers on occasions. Measurements were also made on approximately 8000 downhole sub-samples from shallow cores and boreholes. Data from other UK organisations have also been added to the PSA dataset. The data are stored as part of the National Geoscience Data Centre (NGDC) and the Marine Environmental Data and Information Network (MEDIN) Data Archive Centre (DAC) for Geology and Geophysics. Data are delivered via the BGS Offshore GeoIndex www.bgs.ac.uk/GeoIndex/offshore.htm Seabed Sediment Data layers.
The purpose of this digital dataset is to provide accurate mapping of the distribution of sea-bed sediment types. Sea-bed sediments can only be mapped offshore, where the most recent deposits commonly form a veneer or superficial layer of unconsolidated material on the sea-bed. The dataset is produced for use at 1:250,000 scale. The boundaries between sediment classifications or types are delineated using sample station particle size analyses and descriptions, seafloor topography derived from shallow geophysical data and where available multibeam bathymetry and backscatter and side scan sonar profiles. The sediment types present on the sea-bed are of importance to a range of groups, including marine habitat mappers, marine spatial planners, the offshore construction and development sector, and the dredging and aggregate industries. These groups require detailed information on the nature of the sea-bed, including the sediment types present. The DiGSBS250k dataset has been created as vector polygons and are available in a range of GIS formats, including ArcGIS (.shp), ArcInfo Coverages and MapInfo (.tab). More specialised formats may be available but may incur additional processing costs.
Linear features (shown as polylines) represent six classes of geological structural features e.g. faults, folds or landforms e.g. buried channels, glacial drainage channels at the ground or bedrock surface (beneath superficial deposits). Linear features are associated most closely with the bedrock theme either as an intrinsic part of it for example marine bands or affecting it in the case of faults. However landform elements are associated with both bedrock and superficial deposits. The linear features are organised into seven main categories: Alteration area, indicating a zone of change to the pre-existing rocks due to the application of heat and pressure that can occur round structural features such as faults and dykes. Fault, where a body of bedrock has been fractured and displaced by a large scale process affecting the earth's crust. Fold, where strata are bent or deformed resulting from changes or movement of the earth's surface creating heat and pressure to reshape and transform the original horizontal strata. Folds appear on all scales, in all rock types and from a variety of causes. Fossil horizons, where prolific fossil assemblages occur and can be used to help establish the order in which deposits were laid down (stratigraphy). These horizons allow correlation where sediments of the same age look completely different due to variations in depositional environment. Landforms, define the landscape by its surface form; these include glacial features such as drumlins, eskers and ice margins. Mineral vein, where concentrations of crystallised mineral occur within a rock, they are closely associated with faulting but may occur independently. Rock, identifies key (marker) beds, recognised as showing distinct physical characteristics or fossil content. Examples include coal seams, gypsum beds and marine bands. The data are available in vector format (containing the geometry of each feature linked to a database record describing their attributes) as ESRI shapefiles and are available under BGS data licence.
In 1992, BIRPS joined with the Indonesian Marine Geological Institute to record two long multichannel normal-incidence reflection profiles, one of which is DAMAR, the other TIMOR, and one short profile (API) close to the volcano Gunung Api. The survey provides a modern analogue to tectonics hypothesized to have occurred across the Iapetus suture zone of northern England 450-400 Ma. The Banda Arc of Indonesia near the island of Timor is widely recognized as the premier example of the active subduction of continental crust and lithosphere beneath oceanic lithosphere. The crossing of a modern island arc and close passage to active volcanoes was intended to image reflections associated with magma in the crust and uppermost mantle.
The Quaternary deposits summary lithologies dataset is a digital geological map across the bulk of the UK Continental Shelf (UKCS), for areas up to a water depth of 200 m, which groups the deposits into classes based on similar engineering geology characteristics. The map is derived from (unpublished) BGS 1:1,000,000 scale Quaternary digital geological mapping, so is effective at that scale. The map was produced in 2014 in collaboration with, and co-funded by, The Crown Estate as part of a wider commissioned project to assess seabed geological constraints on engineering infrastructure across the UKCS. The data are held by the BGS as an ESRI ArcGIS Shapefile The divisions on the map combine the Quaternary deposits into 7 categories of similar strength and lithological variability, each with a Category title that summarises their main lithological character: diamict; firm to hard interbedded (layered); firm to hard mud; sand and gravel; soft interbedded; soft mud; undifferentiated. These categories can be used as a basis for assessing, in conjunction with a range of other geological factors, the geological constraints on engineering structures at or close to the seabed.
This layer of the map based index (GeoIndex) shows sites where regularly monitored rest water level data are available, usually covering a long time period. The data shows seasonal fluctuations in the water table and responses to periods of high or low rainfall.
Data identifying landscape areas (shown as polygons) attributed with geological names. The scale of the data is 1:250 000 scale providing a generalised geology. Onshore coverage is provided for all of England, Wales, Scotland and the Isle of Man. Data are supplied as two themes: bedrock and linear features (faults), there is no superficial, mass movement or artificial theme available onshore at this scale. Bedrock geology describes the main mass of solid rocks forming the earth's crust. Bedrock is present everywhere, whether exposed at surface in outcrops or concealed beneath superficial deposits or water bodies. Geological names are based on the lithostratigraphic or lithodemic hierarchy. This means rock bodies are arranged into units based on rock-type and geological time of formation. Where rock-types do not fit into the lithostratigraphic scheme, for example intrusive, deformed rocks subjected to heat and pressure resulting in new or changed rock types; then their classification is based on their rock-type or lithological composition. This assesses visible features such as texture, structure, mineralogy. Data identifying linear features (shown as polylines) represent geological faults at the ground or bedrock surface (beneath superficial deposits). Geological faults occur where a body of bedrock has been fractured and displaced by large scale processes affecting the earth's crust (tectonic forces). The faults theme defines geological faults (shown as polylines) at the ground or bedrock surface (beneath superficial deposits). The data are available in vector format (containing the geometry of each feature linked to a database record describing their attributes) as ESRI shapefiles and are available under BGS data licence.