Abstract Petroleum systems within rifted margin basins affected by volcanism continue to remain challenging for the exploration of hydrocarbons, most notably owing to the volume of intrusions that pose imaging, drilling and exploration problems. Typically, intrusions possess small thermal aureoles, but despite this, there is evidence that intrusions could none the less be responsible for the generation of commercial volumes of hydrocarbons. Here we shed new light on this petroleum systems challenge by integrating organic geochemical and Raman spectroscopic techniques to produce potential volumetric data for hydrocarbons generated as a result of igneous intrusion. The results indicate that, in areas with immature source rock intervals, it may be possible for intrusions to generate volumes of oil that would be capable of comfortably filling likely known oil reservoirs. This is a critical step forward in integrating several analytical techniques, indicating that under the right conditions there is the potential for hydrocarbon generation as a result of igneous intrusion.

Abstract The British Geological Survey (BGS) petrology collections contain almost 1500 Scottish rock samples (with thin sections) deposited by Archibald Geikie, including BGSS1, an analcime gabbro from Salisbury Crags, Edinburgh. High-quality thin section images are now available from the BGS’s Britrocks online database. The geospatial distribution of these samples is analysed. They reflect the development of geological mapping and igneous petrology in Scotland from the 1850s to the 1890s. Geikie had the opportunity to study Nicol’s original thin sections in 1851 and he met both Sorby and Zirkel, early pioneers of petrography. Lacking management support, he cut many of his own thin sections while mapping the Clyde Plateau lavas during the 1860s, leading to publications on Carboniferous and Tertiary volcanism. When appointed Director of the newly formed Geological Survey of Scotland in 1867, he was able to establish a petrological laboratory in Edinburgh. Time pressures resulting from his subsequent promotion to Director-General, and increasing quantities of metamorphic rocks, then necessitated the appointment of Hatch and Teall as petrographers for the Survey. Teall’s work was particularly important in the detailed petrography of the gneisses and mylonites associated with the Highlands Controversy. Supplementary material: The rock samples deposited in the Survey collections by Archibald Geikie are listed on a spreadsheet, which will be updated when more slides are imaged or if URLs change. The spreadsheet is available at https://doi.org/10.6084/m9.figshare.c.4360664 .

Abstract Archibald Geikie played a fundamental, but largely unrecognized, role in the establishment of the Scottish oil shale industry by providing James ‘Paraffin’ Young with the critical information about the location, thickness and probable geographical extent of organic-rich shales during their field visit in 1858. Young subsequently used the observations to determine where to buy leases for commercial oil shale extraction and production before any competitors emerged. Geikie acquired his critical knowledge of the area whilst preparing the first map and memoir of the Edinburgh area published in 1859 and 1861, respectively. In 1866, Young’s Paraffin Light and Mineral Oil Company Limited opened the Addiewell works, the largest oil shale works in the world at the time. By the late 1860s, there were over 120 works distilling oil in Scotland, mostly from the shales of the Lothians. Eventually, more than 22 million gallons of crude oil a year were produced in the Midland Valley in an industry that employed c. 40 000 people. Although the Scottish oil shale industry eventually closed in the 1960s, Geikie’s legacy lives on through a better understanding of the geology of the Midland Valley and the renewed interest in extracting oil and gas from the shales buried beneath.

Abstract The UK Department of Energy and Climate Change (DECC) commissioned the British Geological Survey (BGS) to summarize the available geological knowledge, integrate new seismic mapping and well analysis, and make preliminary in-place resource assessments for the three most prospective areas onshore Britain to foster a greater understanding of the unconventional shale resource potential in advance of the 14th Landward Licensing Round. The first study, published in June 2013, reviewed the Carboniferous Bowland–Hodder shales across central Britain where a large volume of in-place gas was assessed to be present. The second study, of the Jurassic shale of the Weald Basin in southern England, published in May 2014, concluded that owing to insufficient burial there was no significant Jurassic shale gas potential, but there could still be shale oil resources at several levels in the centre of the basin. The third study, published in June 2014, covered the Midland Valley of Scotland where both oil and gas potential in Carboniferous shales was identified. A large volume of in-place gas and oil resource has been assessed to be present. However, not enough is known at the time of writing to estimate a recovery factor or to estimate potential producible reserves. This paper summarizes the results of the BGS reports and their impact on the subsequent licensing process in England.

Abstract The story of UK onshore exploration goes back to the days of World War I and was prompted by the increasing use of oil for the war effort. The war was drawing to a close as the campaign commenced in 1918. The UK government sponsored the drilling with a budget of £1 000 000 and the work was undertaken by S. Pearson & Sons, a UK engineering company owned by Lord Cowdray (Weetman Pearson). Pearson also had oil interests and he owned the Mexican Eagle Company that had had exploration success in Mexico. Pearson hired a team of American geologists to select suitable drilling locations in the UK. The Carboniferous rocks in the area surrounding the Derbyshire Dome in England and the Midland Valley in Scotland were chosen because of their similarity to the oil-producing areas of Pennsylvania and West Virginia in the USA. Eleven wells were sunk: seven in Derbyshire, two in North Staffordshire and two in Scotland. The first well to be spudded was at Hardstoft in Derbyshire in October 1918 and it was also the first oil discovery. The geological reasoning behind the selection of the drilling sites will be compared with the actual results from 1918–22.