{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T02:13:02Z","timestamp":1760235182312,"version":"build-2065373602"},"reference-count":37,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2021,7,27]],"date-time":"2021-07-27T00:00:00Z","timestamp":1627344000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003593","name":"Conselho Nacional de Desenvolvimento Cient\u00edfico e Tecnol\u00f3gico","doi-asserted-by":"publisher","award":["201943\/2014-0"],"award-info":[{"award-number":["201943\/2014-0"]}],"id":[{"id":"10.13039\/501100003593","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Minerals"],"abstract":"<jats:p>The Baixo Alentejo Flysch Group (BAFG) is an important stratigraphic unit that covers over half of the South Portuguese Zone (SPZ) depositional area, and it is composed by three main tectono-stratigraphic units: the M\u00e9rtola, Mira, and Brejeira formations. All of these formations contain significant thicknesses of black shales and have several wide areas with 0.81 wt.%, 0.91 wt.%, and 0.72 wt.% average total organic carbon (TOC) (respectively) and thermal maturation values within gas zones (overmature). This paper is considering new data from classical methods of organic geochemistry characterization, such as TOC, Rock\u2013Eval pyrolysis, and organic petrography, to evaluate the unconventional petroleum system from the SPZ. A total of 53 samples were collected. From the stratigraphical point of view, TOC values seem to have a random distribution. The Rock\u2013Eval parameters point out high thermal maturation compatible with gas window (overmature zone). The samples are dominated by gas-prone extremely hydrogen-depleted type III\/IV kerogen, which no longer has the potential to generate and expel hydrocarbons. The petrographic analyses positioned the thermal evolution of these samples into the end of catagenesis to metagenesis (wet to dry gas zone), with values predominantly higher than 2 %Ro (dry gas zone). The presence of thermogenic hydrocarbon fluids characterized by previous papers indicate that the BAFG from SPZ represents a senile unconventional petroleum system, working nowadays basically as a gas reservoir.<\/jats:p>","DOI":"10.3390\/min11080811","type":"journal-article","created":{"date-parts":[[2021,7,27]],"date-time":"2021-07-27T12:18:31Z","timestamp":1627388311000},"page":"811","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Geochemical Considerations from the Carboniferous Unconventional Petroleum System of SW Iberia"],"prefix":"10.3390","volume":"11","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7971-6196","authenticated-orcid":false,"given":"Gabriel A.","family":"Barberes","sequence":"first","affiliation":[{"name":"Center of Geoscience, Department of Earth Science, Faculty of Science and Technology, University of Coimbra, 3000-272 Coimbra, Portugal"},{"name":"Instituto de Astrof\u00edsica e Ci\u00eancias do Espa\u00e7o, Universidade de Coimbra, 3040-004 Coimbra, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8033-3486","authenticated-orcid":false,"given":"Rui","family":"Pena dos Reis","sequence":"additional","affiliation":[{"name":"Center of Geoscience, Department of Earth Science, Faculty of Science and Technology, University of Coimbra, 3000-272 Coimbra, Portugal"}]},{"given":"Nuno L.","family":"Pimentel","sequence":"additional","affiliation":[{"name":"Instituto Dom Luiz (IDL), Faculdade de Ci\u00eancias, Universidade de Lisboa, 1749-016 Lisboa, Portugal"}]},{"given":"Andr\u00e9 L. D.","family":"Spigolon","sequence":"additional","affiliation":[{"name":"Petrobras\/CENPES, Geochemistry Division, Rio de Janeiro 21941-915, Brazil"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2068-4895","authenticated-orcid":false,"given":"Paulo E.","family":"Fonseca","sequence":"additional","affiliation":[{"name":"Instituto Dom Luiz (IDL), Faculdade de Ci\u00eancias, Universidade de Lisboa, 1749-016 Lisboa, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2932-6851","authenticated-orcid":false,"given":"Przemys\u0142aw","family":"Karcz","sequence":"additional","affiliation":[{"name":"Polish Geological Institute\u2014National Research Institute Lower Silesian Branch in Wroc\u0142aw, 53122 Wroc\u0142aw, Poland"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3896-2013","authenticated-orcid":false,"given":"Marco C.","family":"Azevedo","sequence":"additional","affiliation":[{"name":"3D Seismic Lab, School of Earth and Ocean Sciences, Cardiff University, Cardiff CF10 3AT, UK"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6106-8285","authenticated-orcid":false,"given":"Maria Teresa","family":"Barata","sequence":"additional","affiliation":[{"name":"Instituto de Astrof\u00edsica e Ci\u00eancias do Espa\u00e7o, Universidade de Coimbra, 3040-004 Coimbra, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2021,7,27]]},"reference":[{"key":"ref_1","first-page":"28","article-title":"Shale Gas: A Global Resource","volume":"23","author":"Boyer","year":"2011","journal-title":"OilField Rev."},{"key":"ref_2","first-page":"1851","article-title":"Introduction to Unconventional Petroleum Systems","volume":"86","author":"Law","year":"2002","journal-title":"Am. 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