Percorrer por autor "Garcia-Lobon, Jose Luis"
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- Pre-Mesoproterozoic crustal architecture and implications for the Mesoproterozoic evolution of the SW Angolan Shield from structural, geochemical, and isotopic evidence [Resumo]Publication . Merino-Martínez, E.; Ferreira, Ezequiel; Valverde-Vaquero, Pablo; Rodrigues, José Feliciano; Escuder-Viruete, Javier; Garcia-Lobon, Jose Luis; Beranoaguirre, Aratz; Feria, María Carmen; Rey-Moral, Carmen; Silva, Paulo Bravo; González-Cuadra, Pablo; Sousa, João Carlo; Potti, Julián; Máximo, J.; Gutiérrez-Medina, M.; Gumiel, J.C.; Galán, Gustavo; Mochales, Tania; Manuel, José; Manuel, José; Tassinari, Colombo C. G.; Montero, P.; Sato, Kei; Fuenlabrada, José Manuel; Galindo, CarmenABSTRACT: Several studies suggest the existence of multiple tectonic domains within the Angolan Shield [1], yet the Archaean to Palaeoproterozoic basement of SW Angola and NW Namibia remains largely unexplored. Similarly, distinct Mesoproterozoic (1534–1065 Ma) igneous suites are documented in the SW Angolan Shield, including the largest known gabbro-anorthosite complex (~42,500 km²), the Kunene Complex (KC), but the geological evolution of the region during the Mesoproterozoic is still debated. Traditionally linked to anorogenic contexts [2], recent studies propose a collisional setting for the KC [3]. A combined isotopic (U-Pb, Sr-Nd), gravimetric, and structural approach allows for a refined crustal framework of the SW Angolan Shield and provides new insights into the emplacement of the KC and the regional evolution of the southern Congo Craton. This integrated dataset delineates several Archaean to Palaeoproterozoic domains surrounding the KC, featured by a specific gravimetric response and geochronological time span: Cassinga Zone (2667–2568 Ma and 1982–1971 Ma), Central Eburnean Zone (2038–1947 Ma; intruded by 1844–1744 Ma magmatism in its southern region, the Lubango Area), Namibe and Epupa Zones (1861–1739 Ma), and the Kalahari Area (~1775 Ma?). These contrasting crustal domains significantly influenced the genesis and emplacement of the KC.
- Pre-Mesoproterozoic crustal framework and Mesoproterozoic evolution of the SW Angolan Shield: structural, geochemical, and isotopic insights from the Kunene Complex and surrounding basementPublication . Merino-Martínez, E.; Ferreira, Ezequiel; Valverde-Vaquero, Pablo; Rodrigues, José Feliciano; Escuder-Viruete, Javier; Garcia-Lobon, Jose Luis; Beranoaguirre, Aratz; Feria, María Carmen; Rey-Moral, Carmen; Silva, Paulo Bravo; González-Cuadra, Pablo; Sousa, João Carlo; Potti, Julián; Máximo, J.; Gutiérrez-Medina, M.; Gumiel, J.C.; Galán, Gustavo; Mochales, Tania; Manuel, José; Cordeiro, Domingos; Tassinari, Colombo C. G.; Montero, P.; Sato, Kei; Fuenlabrada, José Manuel; Galindo, CarmenABSTRACT: The southwestern Angolan Shield hosts the Earth's largest Mesoproterozoic massif-type anorthosite complex (up to 53,500 km(2)), the Kunene Complex (KC). This complex is the result of a long-lived (similar to 200 Ma) episodic emplacement of coalescent magmatic pulses. The recent acquisition of multidisciplinary data during the PLANAGEO project has significantly enhanced our understanding of the Precambrian crustal framework from the southwestern Angolan Shield. Combined multi-isotope, structural and geophysical data reveals distinctive crustal zones in the southwestern Angolan Shield that clearly influenced KC's emplacement within a back-arc setting. The spatio-temporal arrangement of KC pulses suggests westwards magma migration within a complex contractional regime involving large strike-slip systems. A long-lasting and extensive accretionary orogen was responsible for the tectono-thermal activity recorded during most of the Mesoproterozoic. Crustal thinning and partial melting of isotopically heterogeneous lower-crustal sources through mantle upwelling promoted the episodic felsic magmatism contemporaneous with the KC. Crustal contamination processes are evident in gabbroanorthosites, indicating mantle metasomatism and interaction with wall-rocks and granite melts during ascent, upwelled by lateral-driven forces. Deposition of extensive metasedimentary sequences (<1.26 Ga) covering the KC, along with 1.23-1.07 Ga sublithospheric and mantle-derived magmatism, indicate a shift from a compressional to an extensional regime during late-Mesoproterozoic times. Regional correlations with other Mesoproterozoic units in African and Brazilian counterparts suggest a shared geological evolution, despite potential differences in tectonic setting. These findings supports a refined geological model for the Mesoproterozoic evolution of the southwestern part of the Congo Craton.
- SedDARE-IB: an open-access repository of sediment data for the Iberian Peninsula and its continental marginsPublication . Torne, Montserrat; Alves, Tiago M.; Jimenez-Munt, Ivone; Carvalho, João; Ayala, Conxi; Ramalho, Elsa; Gomez-Garcia, Angela Maria; Matias, Hugo; Heida, Hanneke; Balaguera, Abraham; Garcia-Lobon, Jose Luis; Verges, JaumeABSTRACT: Sediments provide valuable information for geologists and geophysicists whenever they strive to understand, and reproduce, the geological evolution, lithology, rock properties, seismic response, and geohazards of a region. The analysis of sedimentary sequences is thus useful for the interpretation of depositional environments, sea-level change, climate change, and recognition of the sediments' source areas. By integrating sedimentary data into geophysical modeling, such interpretations are improved in terms of their accuracy and reliability. To further help our understanding of the Iberian Peninsula's geological evolution, geological resources, and geohazards, this work presents to the scientific community the SedDARE-IB data repository. This repository includes available data on the depth to the Base of the Cenozoic and Top of the Paleozoic stratigraphic markers for the Iberian Peninsula, the surrounding West Iberian Atlantic Margin and Western Mediterranean Neogene basins, or the acoustic basement as interpreted for the Valencia Trough and Alboran Mediterranean basins. As an example of the broad applicability of the data included in SedDARE-IB, we investigate how sediment thickness affects the depth to the 150 degrees C isotherm in specific basins, as commonly used in geothermal exploration. The calculated trend suggests that, given constant measured surface heat flow and thermal conductivity, the 150 degrees C isotherm becomes shallower as the sediment thickness increases, until a critical threshold value is reached for the latter. The SedDARE-IB database has been compiled thanks to a Portuguese-Spanish collaboration promoting open data exchange among institutions and research groups. SedDARE-IB is freely available at 10.20350/digitalCSIC/16277 (Torne et al., 2024), bringing opportunities to the scientific, industrial, and educational communities for diverse applications.
- The UTE-PLANAGEO Project (National Geology Plan of Angola). Objectives, methods, and resultsPublication . Garcia-Lobon, Jose Luis; Merino-Martinez, Enrique; Fernández, J.; Carvalho, João; Batista, Maria Joao; Escuder, Javier; Lisboa, Jose; Martín-Banda, Raquel; Francés, Alain Pascal; Ramalho, Elsa; Martín-Méndez, I.; Rey-Moral, Carmen; Feria, María Carmen; Mochales, Tania; Ferreira, Ezequiel; Cuervo, I.; Manuel, José; Victorino, Américo da MataABSTRACT: The National Geology Plan of Angola (PLANAGEO) has been one of the most important Angolan infrastructure projects throughout the past twenty years. The objectives of PLANAGEO were: (a) to enhance Angola's geological and mineral resources knowledge; (b) to foster diversification of the national economy; and, (c) to attract foreign investment and promote the country development. The project integrated regional interdisciplinary geological surveys, including geological/aerogeophysical/geochemical mapping, raw materials and mineral resources prospecting, as well as specific studies in target areas. The project was launched by the Angolan government (Presidential Resolution 52/09), and implemented by the Geological Survey of Angola (IGEO), under the oversight of the Angolan Ministry of Mineral Resources, Oil and Gas (MIREMPET). In 2011, UTE consortium, a joint venture of IGME, the National Laboratory of Energy and Geology of Portugal (LNEG) and the Spanish company Impulso Industrial Alternativo (IIA) bid the call for tenders. In 2013 IGEO awarded UTE a contract to undertake PLANAGEO´s activities in the southwestern region of Angola, covering roughly 480.000 km2. From July of 2014 to the end of 2022, the UTE consortium conducted interdisciplinary studies and investigations that resulted in a comprehensive collection of maps and scientific reports and documents, comprising: Airborne geophysical mag/rad mapping. Geological mapping at 1:250.000 scale (and 1:500.000 and 1:1.000.000 synthesis). Geological mapping at 1:100.000 scale in selected areas. Geochemical mapping at 1:250.000 scale. Raw materials and Mineral resources mapping in target areas, at 1:50.000 scale.