New insights on subsurface energy resources in the Southern North Sea Basin area

The Southern North Sea Basin area, stretching from the UK to the Netherlands, has a rich hydrocarbon exploration and production history. The past, present and expected future hydrocarbon and geothermal exploration trends in this area are discussed for eight key lithostratigraphic intervals, ranging from the Lower Carboniferous to Cenozoic. In the period between 2007 and 2017, a total of 95 new hydrocarbon fields were discovered, particularly in Upper Carboniferous, Rotliegend and Triassic reservoirs. Nineteen geothermal systems were discovered in the Netherlands onshore, mainly targeting aquifers in the Rotliegend and Upper Jurassic/Lower Cretaceous formations. Although the Southern North Sea Basin area is mature in terms of hydrocarbon exploration, it is shown that with existing and new geological insights, additional energy resources are still being proven in new plays such as the basal Upper Rotliegend (Ruby discovery) for natural gas and a new Chalk play for oil. It is predicted that hydrocarbon exploration in the Southern North Sea Basin area will probably experience a slight growth in the coming decade before slowing down, as the energy transition further matures. Geothermal exploration is expected to continue growing in the Netherlands onshore as well as gain more momentum in the UK

Post late Paleozoic tectonism in the Southern Catalan Coastal Ranges (NE Spain), assessed by apatite fission tracks analysis

We report the first apatite fission-track thermochronologic data for 17 samples from the southern Catalan Coastal Ranges of NE Spain. Thermal histories of Carboniferous metasediments, Late Hercynian intrusions and Lower-Triassic Buntsandstein sediments from three tectonics blocks, Miramar, Prades and Priorat, are derived and interpreted within the geodynamic framework and tectonic evolution of the region. The apatite fission-track ages range from 198 ± 24 to 38 ± 5 Ma and mean fission-track lengths are all < 13.3 μm. Samples throughout the study area underwent total track annealing during the Late Hercynian magmatic episode, followed by fast cooling prior to the deposition of Lower Triassic sediments. The Lower Triassic sediments and basement rocks underwent a temperature increase during a first Mesozoic rift phase in Middle Triassic-Early Jurassic times resulting in the complete or near complete annealing of the fission-tracks. During a second Mesozoic rifting stage, in Late Jurassic to Early Cretaceous time, differential tectonic block activity is observed in the three studied tectonic blocks. Subsequently, during Late Cretaceous a long-period of thermal stability, detected in all samples, is related to the post-rift episode. The onset of fast cooling registered in the apatite fission track system during Paleogene times is related to the Pyrenean orogeny. Compressional forces associated with the ongoing southern migration of the convergence forces at the Iberian plate boundaries caused unroofing of about 2-3 km of material of the Prades and northwestern flank of the Priorat block. Extensional collapse in Late Oligocene-Miocene related to the Western Mediterranean rifting triggered the denudation of about 2 km of material from the southeastern flank of the Miramar, Prades and Priorat blocks. © 2002 Elsevier Science B.V. All rights reserved

Multistage tectonic block movements in the Catalan Coastal Ranges (NE Spain) since late Paleozoic assed by apatite and zircon fission-track, and (U-Th)/He. 27th assembly of the European Geophysical Society

Multistage tectonic block movements in the Catalan Coastal Ranges (NE Spain) since late Paleozoic assed by apatite and zircon fission-track, and (U-Th)/He. 27th assembly of the European Geophysical Societ

Tectonothermal evolution of the northeastern margin of Iberia since the break-up of Pangea to present, revealed by low-temperature fission-track and (U-Th)/He thermochronology. A case history of the Catalan Coastal Ranges

The Catalan Coastal Ranges (CCR) form part of the northeastern Iberian Mediterranean margin. This margin typifies the transition zone between the thickened crust of the Pyrenees and Ebro Basin (32 to 40 km), and the extremely thinned continental crust of the offshore Valencia Trough (8 km). Despite intensive geological research in recent decades, the issue of the unsolved thermochronological history has hardly been addressed for the Catalan Margin. This study provides for the first time a continuous low-temperature thermochronological dataset covering the period from Late Paleozoic to present-day. More than 100 analyses have been performed in an area less than 200 km long by 50 km wide. Zircon and apatite fission-track (ZFT and AFT) results of the Hercynian basement yield cooling ages between 254 ± 41-104 ± 16 Ma and 223 ± 27-16 ± 3 Ma, respectively. Apatite (U-Th)/He ages range between 58 ± 3 and 2.0 ± 0.2 Ma. These thermochronological data provide evidence for a very active geothermal past, revealing above all an important thermal period coeval with the Triassic-Early Jurassic break-up of Pangea. Hereby we discuss and suggest various mechanisms responsible for the elevated crustal temperatures detected. This new dataset also provides new constraints on the allocation of areas where exhumation/uplift occurred synchronous with some tectonic phases, the widespread presence of hydrothermal mineralizations and the present-day overmaturity state of the Mesozoic sediments, with regard to oil potential, in the CCR. Despite the local scale of the Catalan Margin, the very detailed study here presented sheds some light on the geological implications of results from other more regional thermochronological studies on the Iberian Microplate. Studies that yield similar Mesozoic thermochronological record for areas that also experienced extensional fracturing and subsidence during the break-up of Pangea. © 2006 Elsevier B.V. All rights reserved

Thermal impact of the break-up of Pangea on the Iberian Peninsula, assessed by thermochronological dating and numerical modelling

Thermochronological studies of Variscan basement in Iberia yield cooling ages typically younger than ~ 200 Ma. In this paper, we explore the regional implications of this recurrent age maximum by examination of low and high temperature thermochronological datasets from all over Iberia. Based on these results, we show that in general the lack of cooling ages older than 200 Ma is the result of several important regional periods of thermal resetting. Resetting took place in areas of extension and burial during the Mesozoic break-up of Pangea. Evidence for large scale magmatism and mineralisation is found in Iberia during the Mesozoic, since at that time Iberia formed part of the Central Atlantic Magmatic Province and a large mineralization province extending from North Africa to Western Europe. Numerical modelling allows us to assess the conditions under which rocks in the upper crust may have been thermally reset and the mechanisms likely involved. Results show that active rifting combined with shallow magmatism, and to a lesser extent deep sedimentary burial, could have led to an increase of the geothermal gradient up to ~ 73 °C/km and the reset of thermochronometers with closure temperatures up to 200 °C. Yet, we suggest that also hydrothermal activity, associated to extensional basins, played an important role to the increase of temperatures of some basement rocks above 300 °C. © 2009 Elsevier B.V. All rights reserved