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<jats:title>Abstract</jats:title> <jats:p>Geological mapping principles have been applied across planet Earth since William Smith's initial 1815 map. During the Space Age, these principles were applied to smaller moons and planets, appropriately adjusted for remote conditions and data, and revealing “one plate planets” recording Earth's missing chapters. But what of Venus, Earth's “twin”, shrouded in opaque clouds? How can these geological mapping principles be applied to address fundamental questions of planetary history? We outline how Venus geological mapping over the last 35 years has proceeded toward a successively integrated more global picture that has revealed a surface and history unlike Earth or the smaller planetary bodies! The current 1:10M global geological map documents geological units that all formed in the last ∼20% of Venus history. The oldest, Fortunian, involved intense deformation and building of thicker crust (tessera). The Guineverian featured near-global emplacement of vast volcanic plains. The Atlian saw prominent rift zones and large shield volcanoes. The three major phases of activity provide a basis for assessing the geological, atmospheric and geodynamical processes operating earlier in Venus history that led to the preserved record, raising a series of questions to be investigated in the coming decade by an international armada of Venus missions.</jats:p> <jats:p content-type="supplementary-material"> Supplementary material at <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" specific-use="dataset is-supplemented-by" xlink:href="https://doi.org/10.6084/m9.figshare.c.6649331">https://doi.org/10.6084/m9.figshare.c.6649331</jats:ext-link> </jats:p>

<jats:title>Abstract</jats:title> <jats:p>In the 1960s, anticipating the award of concessions in the Gulf of Thailand, BP carried out reconnaissance geological mapping over all of Southern Thailand including its Gulf islands.</jats:p> <jats:p>The resulting eight geological maps at 1:250 000 scale provided a database that underpinned discussions of Thailand's place in global plate-tectonic reconstructions that were emerging at that time. In particular, new light was thrown on the Paleozoic succession, and important differences were found between the Upper Thai Peninsula and the Lower Peninsula (respectively, NW and SE of the prominent bend in the peninsula's outline). The Phuket Group of the Upper Peninsula is a very thick diamictite-bearing succession of possible Devonian to Early Permian age, apparently sourced in the west, a region now occupied by the Indian Ocean. That in turn suggested a possible Gondwana origin for SE Asia, a contentious concept at the time, but one that is now widely accepted.</jats:p> <jats:p>The emphasis of field mapping these days is on obtaining detailed data that necessarily means over areas of limited extent. But a very broad regional mapping project such as BP's in Thailand revealed stratigraphic and tectonic insights that could be revealed only from a wide-ranging regional study of this kind.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The study of magmatic and metamorphic processes is challenged by geological complexities like geochemical variations, geochronological uncertainties, and the presence/absence of fluids and/or melts. However, by integrating petrographic and microstructural studies with geochronology, geochemistry, and phase equilibrium diagrams investigations of different key mineral phases, it is possible to reconstruct pressure-temperature-deformation-time histories. Using multiple geochronometers in a rock can provide a detailed temporal account of its evolution, as these geological clocks have different closure temperatures. Given the continuous improvement of existing and new in-situ analytical techniques, this contribution provides an overview of frequently utilised petrochronometers such as garnet, zircon, titanite, allanite, rutile, monazite/xenotime, and apatite, by describing the geological record that each mineral can retain, and explaining how to retrieve this information. These key minerals were chosen as they provide reliable age information in a variety of rock types and, when coupled with their trace element composition, form powerful tools to investigate crustal processes at different scales. This review recommends best applications for each petrochronometer, highlights limitations to be aware of, and discusses future perspectives. Finally, this contribution highlights the importance of integrating information retrieved by multi-petrochronometer studies to gain an in-depth understanding of complex thermal and deformation crustal processes.</jats:p>

<jats:title>Abstract</jats:title> <jats:p> The regional character of organic matter type and depositional conditions of Pendleian, Brigantian and Arnsbergian mudstones between the Craven Basin and the Widmerpool Gulf was compared through interpretation of biomarker and pyrolysis data from 201 samples recovered from 9 boreholes. The Carboniferous seaways have been determined to commonly host dysoxic conditions, enabling preservation of a mixture of marine and terrestrial organic matter types. Photic zone anoxia evidenced by aryl-isoprenoids was determined to be persistent during ‘marine’ conditions represented by marine band, high sea level and carbonate facies. Observation and correlation of diasteranes and T <jats:sub>s</jats:sub> /T <jats:sub>m</jats:sub> ratios within the samples and to other maturity parameters highlighted a significant clay mineral catalytic and/or hydrocarbon retention effect in the samples. This influenced both biomarkers as well as T <jats:sub>max</jats:sub> thermal maturity data reducing the reliability of such results in interpreting burial and ultimately reserve potential. </jats:p> <jats:p content-type="supplementary-material"> Supplementary material at <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" specific-use="dataset is-supplemented-by" xlink:href="https://doi.org/10.6084/m9.figshare.c.6988037">https://doi.org/10.6084/m9.figshare.c.6988037</jats:ext-link> </jats:p>

<jats:title>Abstract</jats:title> <jats:p> Detrital heavy minerals have helped address geologically complex issues such as the nature and origin of the early terrestrial crust, the growth and evolution of the continental crust, and the onset of plate tectonics, together with palaeogeographic and supercontinent cycles reconstructions. With the advent of <jats:italic>in situ</jats:italic> analytical techniques and a more complete understanding of trace element behaviour in rock-forming and accessory minerals, we have now at our disposal a powerful suite of tools that we can apply to multiple proxies found as detrital minerals. These can be <jats:italic>in situ</jats:italic> dating, trace element or isotopic tracing applied to both mineral hosts and their inclusions. We opted to showcase minerals that occur as primary minerals in a wide range of rock compositions and that can provide reliable age information. Additionally, over recent decades their chemistries have been tested as proxies to understand crustal processes. These are zircon, garnet, apatite, monazite, rutile and titanite. We include an overview and provide some approaches to overcome common biases that specifically affect these minerals. This review brings together petrological, sedimentological and geochemical considerations related to the application of these detrital minerals in crustal evolution studies, highlighting their strengths, limitations and possible future developments. </jats:p>

<jats:title>Abstract</jats:title> <jats:p> The Barberton Granite Greenstone Belt remains a key location in the debate concerning the nature of Archaean tectonic processes. Much work has focused on deciphering the tectonic significance of the <jats:italic>c.</jats:italic> 3.23 Ga metamorphism, as this has been correlated with lower geothermal gradient conditions potentially indicating Archaean subduction. However, several studies also found evidence of an earlier, 3.45 Ga metamorphic episode, overprinted by the 3.23 Ga event. Here we apply <jats:italic>in situ</jats:italic> Pb-Pb dating and <jats:italic>P-T</jats:italic> modelling to a large (3 cm diameter) garnet crystal, allowing for the direct dating of the metamorphic conditions obtained from the garnet. The garnet core produced an isochron age of 3435 ± 45 Ma, corresponding to an increase in P and T evolution reaching peak conditions of at least 7 kbar and 700 °C. Analyses obtained from the garnet rim give an isochron age of 3245 ± 41 Ma, corresponding to <jats:italic>P-T</jats:italic> conditions reaching 8-9 kbar and 700 °C. The preservation of two moderate to high pressure events occurring 200 million years apart is consistent with lateral tectonic processes producing crustal thickening at 3.2 Ga and may be a viable process also for the earlier event. </jats:p> <jats:p content-type="supplementary-material"> Supplementary material at <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" specific-use="dataset is-supplemented-by" xlink:href="https://doi.org/10.6084/m9.figshare.c.6724419">https://doi.org/10.6084/m9.figshare.c.6724419</jats:ext-link> </jats:p>

<jats:title>Abstract</jats:title> <jats:p>Monazite-xenotime thermometry is a potentially powerful technique for understanding the evolution of earth systems. While a rich set of experimental and empirical datasets are available for monazite-xenotime equilibria, five different thermometric calibrations yield significantly different results, making this technique difficult to apply in practice. To clarify best practices for monazite-xenotime thermometry, a compilation of published compositional data for monazite and xenotime with independently determined pressure-temperature conditions is evaluated. For each existing thermometer, we examine how closely estimated temperatures match independent empirical temperatures and consider how best to calculate monazite endmembers for each thermometer. Monazite-xenotime thermometry is applied to samples from the Northern Highlands Terrane of northern Scotland, which experienced amphibolite-upper greenschist facies metamorphism and penetrative deformation during the Scandian orogeny. Thermometry data in conjunction with U-Pb dating defines relatively slow regional cooling across the Scandian thrust nappes. Thermometry data closely match quartz c-axis fabric-based deformation thermometry across the structurally lower nappes, suggesting that monazite and xenotime record the timing and temperature of penetrative deformation and shearing. The data suggest that ductile deformation in the hinterland nappes of the Scandian orogen in Scotland occurred as late as 415-410 Ma.</jats:p> <jats:p content-type="supplementary-material"> Supplementary material at <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" specific-use="dataset is-supplemented-by" xlink:href="https://doi.org/10.6084/m9.figshare.c.6724396">https://doi.org/10.6084/m9.figshare.c.6724396</jats:ext-link> </jats:p>

<jats:title>Abstract</jats:title> <jats:p>This volume showcases recent geological, geophysical, and geochemical research on the Carboniferous Bowland Shale Formation, a classic Palaeozoic black shale unit. The Bowland Shale spans ca. 16 Myrs from the upper Visean to mid-Bashkirian, and is perhaps the most important and controversial black shale unit in the UK. The volume focuses on the key Carboniferous basins in the Midlands, northern England, and North Wales. The main basins assessed in the volume are the Craven Basin, including the Bowland sub-basin, the Blacon Basin, the Edale Basin, the Widmerpool Gulf and the Gainsborough Trough. The Bowland Shale and equivalent units are described and interpreted in terms of sedimentary, geochemical, and physical properties and processes, basin-forming events, hydrocarbon prospectivity, mineralization, and heat and fluid flow in the subsurface.</jats:p>

<jats:title>Abstract</jats:title> <jats:p> We evaluated the unconventional hydrocarbon potential of the Holywell Shale Formation, a lateral equivalent of the Bowland Shale Formation deposited in the Blacon Basin. Two cores with Arnsbergian–Chokierian and Kinderscoutian (Namurian, Late Mississippian–Early Pennsylvanian) ages from the Ellesmere Port 1 borehole were sampled for palynological, stable isotope, Rock-Eval 6 pyrolysis and ichnofacies analyses. The study was designed to provide boundary conditions for parameters that are under-represented in the public domain and hamper accurate resource assessments: thermal maturity (through mean random vitrinite reflectance, <jats:italic>R</jats:italic> <jats:sub>r</jats:sub> ), present-day organic matter content, kerogen type, original hydrogen index and original organic matter content. Our results show that the Arnsbergian Core 2 has been buried to a depth equivalent to the bottom of the oil window to the top of the gas window (% <jats:italic>R</jats:italic> <jats:sub>r</jats:sub> = 1.15%–1.29%). The Kinderscoutian Core 1 is too immature to have generated any natural gas (% <jats:italic>R</jats:italic> <jats:sub>r</jats:sub> = 0.91–1.03%). Furthermore, kerogen typing and ichnofacies analysis show that the Bowland Shale Formation is very heterogeneous, with organic matter originating from terrestrial and marine sources. Five palynofacies assemblages are described that range in basin setting from proximal and oxic to distal and anoxic with evidence of episodic connections to the open ocean. The combination of heterogeneity and low thermal maturity restricts the thickness of the Bowland Shale Formation in the Blacon Basin that is prospective for unconventional hydrocarbons. Our results show that these Carboniferous mudstones should not be treated as uniform units with uniform composition and maturity in basin modelling and resource estimates. This undoubtedly has repercussions for future exploration because the contrasting composition and density of the materials making up the Bowland Shale Formation may complicate extraction, while the thermal maturity window significantly narrows the prospective interval. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>The recent shale gas revolution originated in the United States in the late 1990s with the exploration of the Carboniferous Barnett Shale in Texas. Success in a number of additional basins in North America such as the Marcellus, Eagleford and Bakken stimulated a search for similar opportunities elsewhere around the world. Amongst the shales and basins targeted by industry was the Carboniferous Bowland Shale (and equivalents) in northern England.</jats:p> <jats:p>An initial premise that the Barnett represented an excellent analogue for the Bowland lead to overoptimistic reserve estimates which have been shown to be largely incorrect. On the basis of visual inspection of wellbore cores, the Carboniferous Barnett and Bowland shales appear to be very similar. Unfortunately, it is there that the similarity ends. Research carried out for the UKUH project has highlighted important differences adversely impacting propectivity. These can be summarised as basin type/continuity and structural complexity. The total organic carbon (TOC), maturity, mineralogy and thickness of the Bowland Shale and equivalents are broadly similar to the successful US examples.</jats:p> <jats:p>Our conclusion is that the Bowland Shale in the UK does not represent a technically significant resource and in hindsight did not merit the considerable industry and media attention that has been associated with it. A key learning is that fundamental research based on heritage data and modern analytical and modelling techniques should have preceded drilling and fracking operations in northern England.</jats:p> <jats:p content-type="supplementary-material"> Supplementary material at <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" specific-use="dataset is-supplemented-by" xlink:href="https://doi.org/10.6084/m9.figshare.c.7027899">https://doi.org/10.6084/m9.figshare.c.7027899</jats:ext-link> </jats:p>