2024-03-29T07:09:23Z
http://revistes.ub.edu/index.php/index/oai
oai:revistes.ub.edu:article/12091
2022-02-10T17:22:18Z
GEOACTA:SHN
driver
nmb a2200000Iu 4500
"231026 2023 eng "
1696-5728
dc
In memoriam of Andrés Pérez-Estaún
BASTIDA, F.
Universidad de Oviedo.
BUSQUETS, P.
Universitat de Barcelona.
CARBONELL, R.
Consejo Superior de Investigadores Científicas - Institut de Ciències de la Terra Jaume Almera, Barcelona.
HEREDIA, N.
Instituto Geológico y Minero de España, Oviedo.
None
Universitat de Barcelona
2015-04-28 00:00:00
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http://revistes.ub.edu/index.php/GEOACTA/article/view/12091
Geologica Acta; Vol. 13 No 1 (2015)
eng
Drets d'autor (c) 2023 F. BASTIDA, P. BUSQUETS, R. CARBONELL, N. HEREDIA
oai:revistes.ub.edu:article/16095
2022-02-10T17:13:50Z
GEOACTA:SHN
driver
nmb a2200000Iu 4500
"170221 2017 eng "
1696-5728
dc
The Pobei Cu-Ni and Fe ore deposits in NW China are comagmatic evolution products: evidence from ore microscopy, zircon U-Pb chronology and geochemistry
LIU, Y.G.
Key Laboratory for the Study of Focused Magmatism and Giant Ore Deposits, Ministry of Land and Resources, Xi’an Center of Geological Survey Institute of Geological Survey, China University of Geosciences, Wuhan. 388 Lumo Road, Hongshan District, Wuhan 430074, China. College of Earth Science and Resources, Chang’an University.
LI, W.Y.
Key Laboratory for the Study of Focused Magmatism and Giant Ore Deposits, Ministry of Land and Resources, Xi’an Center of Geological Survey
LÜ, X.B.
Institute of Geological Survey, China University of Geosciences, Wuhan. 388 Lumo Road, Hongshan District, Wuhan 430074, China.
HUO, Y.H.
School of Earth Science, Lanzhou University.
ZHANG, B.
Key Laboratory of Orogenic Belt and Crustal Evolution, Peking University.
The Pobei mafic-ultramafic complex in northwestern China comprises magmatic Cu-Ni sulfide ore deposits coexisting with Fe-Ti oxide deposits. The Poshi, Poyi, and Podong ultramafic intrusions host the Cu-Ni ore. The ultramafic intrusions experienced four stages during its formation. The intrusion sequence was as follows: dunite, hornblende-peridotite, wehrlite and pyroxenite. The wall rock of the ultramafic intrusions is the gabbro intrusion in the southwestern of the Pobei complex. The Xiaochangshan magmatic deposit outcrops in the magnetitemineralized gabbro in the northeastern part of the Pobei complex. The main emplacement events related to the mineralization in the Pobei complex, are the magnetite-mineralized gabbro related to the Xiaochangshan Fe deposit, the gabbro intrusion associated to the Poyi, Poshi and Podong Cu-Ni deposits, and the ultramafic intrusions that host Cu-Ni deposits (Poyi and Poshi). The U-Pb age of the magnetite-mineralized gabbro is 276±1.7Ma, which is similar to that of the Pobei mafic intrusions. The εHf(t) value of zircon in the magnetite-mineralized gabbro is almost the same as that of the gabbro around the Poyi and Poshi Cu-Ni deposits, indicating that the rocks related to Cu-Ni and magnetite deposits probably originated from the same parental magma. There is a trend of crystallization differentiation evolution in the Harker diagram from the dunite in the Cu-Ni deposit to the magnetite-mineralized gabbro. The monosulfide solid solution fractional crystallization was weak in Pobei; thus, the Pd/Ir values were only influenced by the crystallization of silicate minerals. The more complete the magma evolution is, the greater is the Pd/Ir ratio. The Pd/Ir values of dunite, the lithofacies containing sulfide (including hornblende peridotite, wehrlite, and pyroxenite) in the Poyi Cu-Ni deposit, magnetite-mineralized gabbro, and massive magnetite, are 8.55, 12.18, 12.26, and 18.14, respectively. Thus, the massive magnetite was probably the latest product in the evolution of the Pobei mafic-ultramafic intrusions. We infer that the Cu-Ni sulfide and Fe-Ti oxide ores in the Pobei area were products of a cogenetic magma at different evolutionary stages; at the late stage, the magma became iron enriched through crystallization differentiation. The magma differentiation occurred in a deep staging magma chamber emplaced in the upper magma chamber. Earlier crystallized olivine with some interstitial sulfides gathered at the bottom of the staging magma chamber because of its greater density. That is to say, the ultramafic magma hosting the Cu-Ni sulfide formed at the bottom of the staging magma chamber, while the magnetite-mineralized gabbro was in the upper part. However, the magnetite-mineralized gabbro injected into the upper magma chamber first and the ultramafic lithofacies containing the olivine and the interstitial Cu-Ni sulfides were subsequently emplaced in the upper magma chamber as crystal mush.
Universitat de Barcelona
2017-03-10 00:00:00
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http://revistes.ub.edu/index.php/GEOACTA/article/view/GeologicaActa2017.15.1.4
Geologica Acta; Vol. 15 No 1 (2017)
eng
Drets d'autor (c) 2017 Y.G. LIU, W.Y. LI, X.B. LÜ, Y.H. HUO, B. ZHANG
oai:revistes.ub.edu:article/18855
2022-02-10T17:14:43Z
GEOACTA:SHN
driver
nmb a2200000Iu 4500
"180621 2018 eng "
1696-5728
dc
Seismic imaging and attribute analysis of Chicxulub Crater central sector, Yucatán Platform, Gulf of Mexico
CANALES-GARCÍA, I.
Posgrado en Ciéncias del Mar y limnología, Universidad Nacional Autónoma de México Ciudad Universitaria, Delegación Coyoacán, 04510 México, México
URRUTIA-FUCUGAUCHI, J.
Programa Universitario de Perforaciones en océanos y Continentes, Instituto de Geofísica, Universidad nacional Autónoma de México, Departamento de Geomagnetismo y Exploración Ciudad Universitaria, Delegación Coyoacán, 04510 México, México.
AGUAYO-CAMARGO, E.
Facultad de Ingeniería, Universidad nacional autónoma de México, Departamento de Geología. Ciudad Universitaria, Delegación Coyoacán, 04510 México, México
Chicxulub Crater, formed ~66Ma ago by an asteroid impact on the southern Gulf of Mexico, is the best preserved of the three large multi-ring basins in the terrestrial record. The crater structure is characterized by a semi-circular concentric ring pattern, marking the crater basin, peak ring, terrace zone and basement uplift. Analysis of a grid of 19 seismic reflection profiles using seismic attributes, marker horizons, contour surfaces and 3-D views is used to investigate the stratigraphy of the central zone. We used interactive software and routine applications to map the impact breccias, breccia-carbonate contact and post-impact carbonates. Four horizons marked by high-amplitude reflectors representing high-impedance contrasts were identified and laterally correlated in the seismic images. Complex trace attribute analysis was applied for petrophysical characterization. Surface contour maps of base and top of stratigraphic packages were constructed, which mapped the impactites and post- and pre-impact carbonate stratigraphy. Basin floor, marked by the contact between the impact breccias and overlying carbonates is shown by laterally discontinuous high-amplitude reflectors. Discontinuous scattered reflectors interpreted as the upper breccias beneath the crater floor, have an average thickness of ~300msm. The Paleogene sedimentary units are characterized by multiple reflectors with lateral continuity, which contrast with the seismic response of underlying breccias. The basal Paleocene sediments follow the basin floor relief. Upwards in the section, the carbonate strata are characterized by horizontal reflectors, which are interrupted by a regional unconformity. Onlap/downlap packages over the unconformity record a period of sea level change.
Universitat de Barcelona
2018-06-21 00:00:00
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http://revistes.ub.edu/index.php/GEOACTA/article/view/GeologicaActa2018.16.2.6
Geologica Acta; Vol. 16 No 2 (2018)
eng
Drets d'autor (c) 2018 Geologica Acta
oai:revistes.ub.edu:article/20023
2022-02-10T17:15:06Z
GEOACTA:SHN
driver
nmb a2200000Iu 4500
"180625 2018 eng "
1696-5728
dc
Chemical and stable isotope composition (18O/16O, 2H/1H) of formation waters from the Carabobo Oilfield, Venezuela
BOSCHETTI, T.
Department of Chemistry, life sciences and Environmental Sustainability, University of Parma Parco Area delle Scienze, 43124, Parma, Italy. http://scvsa-servizi.campusnet.unipr.it/do/docenti.pl/Show?_id=tizbos91#profilo http://orcid.org/0000-0002-5994-9750
ANGULO, B.
Departamento de investigación estratégica en exploración. Instituto Tecnológico Venezolano del Petróleo (INTEVEP), Petróleos de Venezuela S.A. (PDVSA) Apartado 76343, Caracas 1070-A, Los Teques, Venezuela.
QUINTERO, F.
Departamento de investigación estratégica en exploración. Instituto Tecnológico Venezolano del Petróleo (INTEVEP), Petróleos de Venezuela S.A. (PDVSA) Apartado 76343, Caracas 1070-A, Los Teques, Venezuela.
VOLCÁN, J.
Instituto de Ciencias de la Tierra. Universidad Central de Venezuela Apartado 3895, Caracas 1010-A, Venezuela
CASALINS, A.
Estudios integrados, Petrolera Sinovensa Torre BVC, Barcelona 6001, Venezuela
In this short note, we present the first data on stable isotope composition of the oilfield waters from Carabobo area of the Faja Petrolífera del Orinoco “Hugo Chávez” (Orinoco Oil Belt). From a chemical point of view, the formation waters show a main Na-Cl level (TDS up to 30g/l) with a dilution trend toward Na-HCO3 composition (down to 1g/l). Until now, such a clear net chemical compositional trend was ascribed to a meteoric dilution (fresh/ brackish bicarbonate) of the seawater endmember (the saltiest chloride). The isotope results of this study reveal that the seawater mother water was modified during a high-temperature thrusting event (120–125°C), forming 18O-enriched diagenetic water (up to +4‰), which was diluted in recent times by glacial meltwater and presentday meteoric water. The hypothetical presence of flood by a meteoric paleo-water also offers new hints to explain the low API gravity (<10°API biodegraded, extra heavy oil) and composition of the local crude.
Universitat de Barcelona
2018-09-10 00:00:00
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http://revistes.ub.edu/index.php/GEOACTA/article/view/GeologicaActa2018.16.3.2
Geologica Acta; Vol. 16 No 3 (2018)
eng
Drets d'autor (c) 2018 Geologica Acta
oai:revistes.ub.edu:article/38999
2023-01-04T09:08:01Z
GEOACTA:SHN
driver
nmb a2200000Iu 4500
"220915 2022 eng "
1696-5728
dc
Organic-walled tentaculids of Late Devonian (Frasnian) deposits of the Appalachian and Michigan Basins, Laurussia (NY, MI, OH)
Meehan, Kimberly Cynthia
University at Buffalo
Boyle, James T.
University at Buffalo
This is the first report of organic-walled tentaculid remains from Givetian through Frasnian age deposits of the Michigan and Appalachian Basins in western Laurussia. This adds to the geographic scope of similar finds that have been described from the Frasnian through the Famennian in eastern Laurussia. However, those previous specimens were retrieved through palynological preparations and more closely resemble sheath structures rather than the full forms found herein, which were retrieved through complete maceration with ammonium surfactants.
Universitat de Barcelona
2022-01-31 00:00:00
application/pdf
http://revistes.ub.edu/index.php/GEOACTA/article/view/38999
Geologica Acta; Vol. 20 (2022)
eng
Drets d'autor (c) 2022 Geologica Acta