First launched in July 2000, the BGS GeoIndex is a professional digital geological map application and receives over one million views each year.

The current iterations of the GeoIndex Onshore and GeoIndex Offshore applications are now 10 years old and approaching the end of their technical lifespans. The transition to the updated viewer has allowed us to unify the platforms into a single, streamlined tool and increase awareness of the geological data available from BGS. 

Alongside the integration of onshore and offshore data, the includes a number of other notable additions. The refreshed and upgraded user interface has been designed to enhance the user experience, with improved find and filter tools to make it easier to access the relevant data. Direct links to full records have been added to provide deeper insights and there are expanded basemap options, including the latest Ordnance Survey maps and high-resolution satellite imagery.

The beta release also includes core geological data layers, such as 625K- and 50K-scale digital geological mapping and borehole datasets, to allow for focused user testing. We are looking at eventually streamlining some of the other currently available data layers as part of the review, to ensure the new platform is as user friendly as possible.

The BGS GeoIndex is our flagship map viewer and we’ve spent the last few years planning how we can improve the application for our users.

We are excited to share this beta version for testing and to gauge users’ reactions and hope the updated interface will bring many welcome usability improvements.

Steven Richardson, BGS Geospatial Applications Developer.

We would welcome user feedback during this beta phase, and comments can be submitted through the .

Please note: commercial, research and public good level users should continue to use the existing BGS GeoIndex (onshore) and GeoIndex (offshore) applications for professional use until the new platform is formally launched.

Our digital geological maps are a unique national resource. A good understanding of the subsurface is critical for many applications across a wide range of disciplines, including, but not limited to:

• aquifer management
• radioactive waste disposal
• mineral resources
• engineering
• geohazards

Geological maps and digital data help with making investment and planning decisions, assessing hazards and de-risking projects. We are constantly aiming to update and improve our maps, so they are fit for the digital demands of the 21st century.

Why do we want your feedback? 

51ÁÔÆæ is constantly striving to improve its map compilation and dissemination procedures. The maintenance and development of our geological data is a vital part of our survey role. This is especially important as technologies change and offer new ways to disseminate information. The way we collect, compile and produce map data is also changing, so we are reviewing the way our maps and products are developed and delivered to our customers. 

Have your say 

Implementing effective change requires input from all our stakeholder groups and we’d like to hear from you. What are your current priorities? What problems are being solved using our data? What would you like to see in the future? BGS values your input and would appreciate you completing this short questionnaire, providing as much context as possible.

The North Sea Transition Authority (NSTA) has authorised the release of all the well data for onshore hydrocarbon boreholes held by BGS in the National Geoscience Data Centre (NGDC). Unlike borehole data from the North Sea, which has been available free of charge for some time, the data relating to these onshore boreholes was previously only available via data release agents. It is now available free of charge to industry, academics and the public via the , providing a new, free resource that will add to the knowledge necessary to meet net zero objectives.

Why is the data significant?

Few boreholes have been drilled to these depths (over 1 km) onshore in the UK and are almost exclusively a consequence of oil, gas or coal exploration. The oil and gas wells deeply penetrate the crust under the UK mainland and are geographically widespread across the UK.

Unlike coal wells, the oil and gas drilling data is better structured and better conforms to global standards of deep geological and deep geophysical data collection.

Most of the direct knowledge and samples that BGS has access to about the deep geology of the UK are based upon this data.

Why is the data being released?

Data from these deep hydrocarbon wells forms the best dataset to understand the geology of the deep UK subsurface. Widening access to the dataset could enhance the knowledge needed to meet net zero objectives:

• assessing the suitability of UK rocks for extraction of geothermal heat
• storing surplus energy from renewables and waste materials such as carbon dioxide
• identifying potential new mineral resources. 

The data has been provided to BGS under regulation PON 9B, which sets out the records and samples requirements for onshore surveys and wells licensed by the NSTA. The data was previously held for BGS internal science use only, so this release widens the community of scientists who can access this important dataset. It includes the data for all boreholes that have been released (four years post-drilling) and for which BGS holds original geophysical data.

Data is being released using an Open Government Licence, which allows users to copy, publish, distribute and transmit the information, adapt the information and exploit the information commercially and non-commercially, provided that they acknowledge the source of the information.

The NSTA has collected data from more than 2200 onshore wells drilled in the search for oil and gas. Historically, half of that data were released through the 51ÁÔÆæ (BGS) with the rest provided by Data Release Agents on behalf of the NSTA. The new arrangement with the BGS means that all onshore hydrocarbon well data will be available from BGS. This free access to the unique onshore data will support the investment and innovation necessary to enable the ongoing energy transition.

Alan Poole, North Sea Transition Authority Geoscientist

51ÁÔÆæ GeoIndex

The data is available via the on a layer called ‘Onshore UK hydrocarbon well data’ and currently includes over 60 000 logs from 1200 wells and the number is still increasing. All related records in the BGS Borehole Index (which contains summary borehole metadata) have also been marked as open, releasing over 2000 records that were previously marked as confidential in the index.

About the authors

51ÁÔÆæ holds records of 1.5 million boreholes. They are a national asset and are relied upon by various types of users. User improvement is key to enable BGS to deliver the data needed by anyone using subsurface data. Improving the level of information delivered plus improvements in the speed and method of delivery are both crucial for ensuring everyone has access to this valuable dataset.

Why have we made these improvements?

Reviewing the enquiries received to BGS, a common theme preventing easy download of borehole data was the size of the scan. A new API (application programming interface) has been developed to deliver scans by generating multi-page PDFs to provide the data in a more efficient way. 

Instead of an ‘image unavailable’ screen, users will have access to all the open borehole data held by the BGS, with no limitation on size.

As well as improving access to scanned and other image format borehole data, improvements have been made to the graphic log created for AGS files. These amendments have been made in line with discussions with stakeholders, including Yorkshire Water, who wanted to see more information on the graphic log produced from the AGS file.

New features

New features in this release include:

• a new, multi-page PDF version to improve the delivery of scanned borehole records.
• an improved version of the graphical log derived from AGS data
• fields added to the ‘Borehole records’ layer to allow the user to see:
  • the precision at which the location is known
  • if there is a known scan-quality issue

We are hoping that these improvements will help people to access the data better. The next step is to provide better access to the AGS data and further improvements to the API will help accomplish that.

Release date

This release showcases improvements in the delivery of borehole data via the . Changes to the ‘Borehole records’ and ‘AGS boreholes’ layers will go live in the week commencing 24 April 2023, to coincide with the AGS Annual Conference taking place on 27 April 2023.

About the author

51ÁÔÆæ has initiated a new programme of mapping the seabed geology of the UK continental shelf, the first effort to consistently characterise the geology of the seabed in over 25 years.

The latest map offers new fine-scale digital maps featuring the seabed of offshore Yorkshire that contain combined bedrock, sediment, bedrock structure and geomorphology data. This is the third in a series of new, fine-scale maps to be released by BGS, with maps for offshore Anglesey and the Bristol Channel already available online.

The seabed geology maps are intended to support a diverse range of offshore activities and applications, including scientific research, offshore development, conservation efforts and marine management. It is part of a drive by BGS to develop new, fit-for-purpose geospatial products that, combined with the availability of new high-resolution data, can better meet current and future decarbonisation and marine science challenges. The maps are expected to be of interest to developers looking to deploy technology and infrastructure to create renewable energy.

The maps are based primarily on high-resolution bathymetry data collected through the Maritime and Coastguard Agency UK Civil Hydrography Programme. They are further informed by acoustic backscatter data, sediment cores and grab samples, seismic data, and existing onshore and offshore map products (both BGS mapsand publicly available academic and industry products).

The geological character of the seabed and shallow subsurface is often complex, but is not well captured by currently available resources.

By applying a consistent approach nationally, incorporating both classical and innovative mapping approaches, these map products offer a unique resource, providing an excellent insight into complex geology, as well as active environmental processes.

Dayton Dove, BGS Marine Geoscientist.

51ÁÔÆæ is among other public and government organisations to have joined the  (UK CSM), helping to boost marine data and mapping standards. Improved geospatial resources will also provide important evidence for policy and decision makers, who need to consider the increasing demands placed on the marine environment from recreation, marine conservation and protection, resource development, and fisheries.

As well as providing important baseline datasets that can underpin efficiency in marine infrastructure projects, such as siting offshore renewables, the analysis and mapping process also leads to interesting new findings, providing the potential for genuine discovery.

Dayton Dove, BGS Marine Geoscientist.

The maps are available from BGS under the fine-scale maps section of the  and are designed to be viewed at 1:10 000 scale, or offline as downloadable shapefiles.

Other areas to be added as the mapping programme progresses include offshore Orkney, East Anglia, and further areas of offshore Wales.

Other maps in this series:

• Anglesey (Ynys Môn)
• Bristol Channel

Anglesey (Welsh: Ynys Môn) follows the Bristol Channel as the second in a series of new fine-scale maps that contain combined bedrock, sediment, bedrock structure and seabed geomorphology data.

The maps are based on data produced by UK Civil Hydrography Programme of the Maritime and Coastguard Agency, which includes bathymetry data, backscatter imagery, grab samples and other existing datasets such as seismic, sediment texture sheets and existing 1:250000-scale geological maps.

These new resources provide important evidence for policy and decision makers, who need to consider the increasing demands being placed on the marine environment from recreation, marine conservation and protection, fishing and resources (e.g. aggregates). The data may be of particular interest to developers of tidal stream energy devices wanting to deploy technology and infrastructure to create renewable energy and generate clean, low-carbon electricity, making Anglesey a hub for marine energy. 

Priority areas currently being mapped also include Yorkshire and East Anglia, with other areas being added as our fine-scale mapping programme progresses.

The seabed substrate around Anglesey forms a fascinating patchwork of bedrock, glacial deposits and more recent marine sediments. Remarkably well-preserved suites of drumlins can be seen on the sea floor in this area; these were moulded under the last ice sheet as it flowed towards the south-west. When the glacier margin retreated, icebergs began to break off, ploughing grooves that can now be seen on the seabed. Under modern marine conditions, strong currents have produced sand waves that can migrate across parts of the sea floor.

The maps are available from BGS under the fine-scale maps section of the  and are designed to be viewed at 1:10 000 scale or offline as downloadable shapefiles.

Other maps in this series:

• Bristol channel 1:10 000 map

51ÁÔÆæ has begun publishing a new series of high-resolution offshore geological maps showing the distribution of bedrock and sediments that make up the seabed around our coasts. Maps of the Bristol Channel and Anglesey were the first to be published, with further regions such as Yorkshire and East Anglia to follow as our mapping programme progresses.

This article takes a closer look at the seabed featured in the the first map of the series, which stretches along the central part of the Bristol Channel, from south of Swansea Bay in the west to Newport in the east.

The Bristol Channel

The Bristol Channel is a large estuary and river system that extends from the Celtic Sea eastwards to the limit of tidal influence along the River Severn at Gloucester. The channel separates South Wales from Devon and Somerset and has the second-largest tidal range in the world at Avonmouth, with a 12.3 m mean spring range ().

Bedrock geology

The seabed of the Bristol Channel is partially covered by soft sediments (superficial deposits) but much of the area is free of sediment cover, allowing for the detailed mapping and interpretation of bedrock units and features. The bedrock geology recognisable in the bathymetric data will be familiar to anyone who knows the coastline of south-east Wales, which is characterised by low, Carboniferous limestone cliffs surrounded by younger, Triassic- and Jurassic-aged rocks.

The bedrock geology presented on the new maps shows a pattern of small outcrops of highly fractured Carboniferous rocks of the , which would have formed a landscape of hills and valleys following uplift and erosion caused by the Variscan Orogeny. 

A window into the distant past

During the Triassic, this part of Wales was hot and arid with wadis, flash flooding and scree slopes () surrounding the hills and cliffs. The low ground in between featured lakes that deposited mudstones and periodically evaporated to leave salt flats (the ‘red beds’ of the ). These deposits sit unconformably on the Lower Palaeozoic landscape.

During the late Triassic and Lower Jurassic, a marine transgression, or rise in sea level, flooded the landscape. A series of deposits recording this event can be seen in the cliffs of the Vale of Glamorgan and traced off shore (). By the Jurassic, this part of Wales had become marine and units of the were deposited, including the, which is divided into the St Marys Well Bay, Lavernock Shales and Porthkerry members.The youngest bedrock unit identified is the , which records deposition in a shallow, sea-shelf environment.

All of these rocks were subsequently deformed, most likely by the Alpine Orogeny. This was a period of mountain buildingin central and southernEuropeandwest Asia. The orogeny resulted in a network of folds, fractures and faults that is especially apparent in the deformation and offsetting of the rocks in the well-bedded Porthkerry Member and Inferior Oolite Group.

Geological structure

The north-east to south-west orientation of the inner part of the Bristol Channel (which is included in the eastern part of our new dataset) and much of the Severn Estuary is influenced by the Severn Estuary fault zone. This is a dextral, strike-slip fault zone considered to have been active during the early Carboniferous. Comparable north-east to south-west trending faults have been recognised within the eastern part of the area covered by this dataset, where they dissect earlier-formed folds and offset the bedding within the Porthkerry Member.

However, within the central and outer parts of the Bristol Channel, the faults are dominated by:

• a set of west-north-west to east-south-east trending structures
• a locally complex network of north-north-west to south-south-east and north-north-east to south-south-west trending cross-faults

These structures have been digitised as ‘fault observed, displacement unknown’ due to the potential complexity and multiple phases of movement over time. There is also an absence of clear marker horizons or beds within, in particular, the Porthkerry Member.

The east to west trending faults are interpreted as forming part of the central Bristol Channel fault zone, a major fault system that is believed to have developed in response to the extensional reactivation of an underlying Variscan thrust during the Mesozoic. North-west to south-east trending faults within the Bristol Channel, including the Sticklepath–Lustleigh and Watchet (also known as Cothelstone) faults, are interpreted as older Variscan structures that reactivated in response to tectonic events during the Mesozoic and Cenozoic.

Superficial deposits

The superficial sediments identified within the dataset comprise marine deposits that include:

• gravel
• sand
• mud
• sandy mud
• sand and gravel
• mud, sand and gravel

The deposits of sand and gravel within the central part of the dataset are related to areas of potentially mobile sediment within the Bristol Channel. A range of bedforms associated with recent or contemporary marine processes within a tidal-dominated environment has developed upon these superficial sediments.

Linear, ribbon-like areas of sand-and-gravel are located along a marked channel incised into the bedrock, which denotes the course of the palaeo-River Severn and its tributaries. Smaller areas of sand occur to the north and south of this palaeo-river channel, where they occur on relatively flat to very gently dipping areas of bedrock, in particular in the area underlain by the well-bedded limestone and mudstone sequence of the Porthkerry Member.

In some areas, the sediment cover is relatively thin and the bedrock geology can be clearly seen or traced through these superficial deposits, or the superficial deposits are too thin to be clearly represented on a geological map designed to be viewed at the 1:10 000 scale. Consequently, only the more prominent, thicker superficial deposits have been captured (digitised) within the dataset, to provide the user with an indication of the main areas of potentially mobile sediment.

The superficial sediment cover at the eastern end of the mapped area is typically finer grained (mud and sand), reflecting its location within the inner part of the Bristol Channel.

An area of gravel and sand-and-gravel exposed at the north-western end of the dataset may represent a submerged, shallow, coastal sequence, with the sands and gravels infilling an irregular network of tidal channels. The coarse-grained nature of these deposits may, at least in part, result from the subsequent removal (winnowing) of fines (mud) by tidal currents within the high-energy environment of the central Bristol Channel.

The modern channel

The present-day geomorphology of the seabed across the Bristol Channel is influenced by events that occurred throughout the Quaternary. Evidence of fluvial processes is found in the form of the palaeo-River Severn channel and its tributaries. These palaeo-channels are incised into the bedrock in the central and inner parts of the Bristol Channel, with their margins denoted by marked breaks in slope (both convex and concave).

The floors of the larger channels are locally covered by sand and/or gravel, with well-developed bedforms on the surface of these superficial deposits. The predominantly north-to-south trend of the crestlines of the sand waves is consistent with the superficial deposits being variably reworked by tidal currents flowing parallel to the central axis of the Bristol Channel.

Breaks of slope within the largest channel marking the main course of the palaeo-River Severn are considered to mark the variably degraded edges of former river terraces. Elsewhere, the surface of the superficial sediments and bedrock is relatively smooth or incised by long, linear, positive and negative features formed as a result of scouring of the seabed by strong bottom currents.

Accessing the data

These maps are available from BGS under the fine-scale maps section of the  and are designed to be viewed at 1:10 000 scale.

Downloadable data is also available via a commercial data licence, but fee-free for academic research, use by registered charities, or in connection with emergency or civil contingency incidents.

For details please contact iprdigital@bgs.ac.uk.