Article
Geochemistry & Geophysics
P. W. Ball, G. G. Roberts, D. F. Mark, D. N. Barfod, N. J. White, B. H. Lodhia, M. M. Nahdi, S. Garni
Summary: Harrat Rahat is the largest volcanic field in Saudi Arabia and has been active from around 10 Ma to the present day. Recent eruptions at Harrat Rahat have been extensively studied, but the evolution of its oldest lava flows, known as the Shawahit Basalt, is poorly understood. In this study, we collected and analyzed samples from Harrat Rahat, focusing on the Shawahit unit. We found that the volcanic activity at Harrat Rahat was initiated by a mantle plume beneath a thinned lithosphere, and the changes in geochemistry can be attributed to a decrease in melt productivity and contamination.
Article
Geochemistry & Geophysics
Hyun-Ok Choi, Jonguk Kim, Jihye Oh, Chang Hwan Kim, Soon Young Choi, Won Hyuck Kim, Chan Hong Park
Summary: This study utilized mineralogy and geochemistry data from submarine volcanic rocks collected from various seamounts in the southwest of the East Sea to investigate the characteristics of magmas' sources, evolution, and storage conditions. The analyses revealed information about the ages of the samples, the compositions of rocks, and the thermobarometric conditions associated with Quaternary volcanism, shedding light on the formation and evolution of these seamounts.
Article
Geology
PengFei Shan, MingJian Cao, Fred Jourdan, Noreen J. Evans, Xin Ge, JingGui Sun, KeZhang Qin, Chao Zhao
Summary: The Xiaoxi'nancha Au-Cu porphyry deposit in Northeast China is characterized by widespread biotite alteration. The age of Au-Cu mineralization appears to be around 110 million years, younger than the zircon U-Pb age but similar to the molybdenite Re-Os age. The deposit is associated with early Cretaceous granitoids formed during the subduction of the Paleo-Pacific Ocean.
ORE GEOLOGY REVIEWS
(2021)
Article
Geochemistry & Geophysics
Sanna Holm-Alwmark, Fred Jourdan, Ludovic Ferriere, Carl Alwmark, Christian Koeberl
Summary: This study focuses on the Puchezh-Katunki impact structure in Russia, accurately dating its formation to 195.9 +/- 1.0 Ma using 40Ar/39Ar data. The research challenges previous temporal correlations between the impact event and multiple extinction events, emphasizes the importance of careful sample preparation and methodology in overcoming 40Ar issues, and highlights the need for caution when suggesting connections between specific impact events and extinction events.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2021)
Article
Geosciences, Multidisciplinary
Morgan J. Salisbury, Nestor Jimenez, Dan Barfod
Summary: This study examines the geochemical variations in the volcanic area of Intersalar Range in western Bolivia. The results show a correlation between the age and geochemical characteristics of the volcanic rocks and the reararc regions. Furthermore, the Nb/Nb* values indicate the presence of intact mantle lithosphere in the central Altiplano.
FRONTIERS IN EARTH SCIENCE
(2022)
Review
Geosciences, Multidisciplinary
Yang Wu, Xiu-Juan Bai, He-Sheng Shi, Li-Yan He, Hua-Ning Qiu
Summary: This paper provides a review of dating methods relying on the K-Ar and Rb-Sr isotopic decay systems applied in sedimentary rocks. It discusses the sample preparation and analytical techniques associated with these methods and summarizes their applications in various sedimentary settings. The paper also highlights the use of Rb-Sr and 40Ar/39Ar dating in determining depositional ages and trapped ancient atmospheric argon components in chert.
EARTH-SCIENCE REVIEWS
(2023)
Article
Geosciences, Multidisciplinary
Patrick Sugden, Khachatur Meliksetian, Ivan P. Savov, Dan Barfod, Marjorie Wilson, Charles Connor, Gevorg Navasardyan, Edmond Grigoryan, David Manucharyan
Summary: The post-collisional Syunik and Vardenis volcanic highlands host over 200 monogenetic volcanoes, with 12 new high-quality 40Ar/39Ar ages indicating active volcanism in the region since at least the late Miocene. The transition from polygenetic to monogenetic volcanism is dated to around 1 Ma, showing spatial and temporal coupling in the formation of new vents. Despite the waning volcanism in the region, a future pulse of activity is possible.
JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH
(2021)
Article
Geography, Physical
Mirek Groen, Michael Storey
Summary: The age uncertainties of the Greenland ice core timescale are inherently problematic, and radio-isotopic age determination of volcanic ash layers can provide independent verification and improved precision for the older part of the timescale. The study found that the radio-isotopic age is more precise compared to the counted annual ice layers, indicating that the oldest part of the timescale is systematically too young by approximately 740 years. These results provide firmer constraints for testing synchronicity or leads and lags in the late Pleistocene climate system.
QUATERNARY SCIENCE REVIEWS
(2022)
Article
Geography, Physical
Alan L. Deino, Clifford Heil, John King, Lindsay J. McHenry, Ian G. Stanistreet, Harald Stollhofen, Jackson K. Njau, Joshua Mwankunda, Kathy D. Schick, Nicholas Toth
Summary: The Olduvai Gorge Coring Project in Tanzania drilled cores at three sites in the Olduvai Basin, developing a chronostratigraphic framework. Through dating, paleomagnetic stratigraphy, and tephrochemical correlation, they obtained realistic age estimates. The age models revealed varying sedimentation rates in the basin's history and provided new estimates for the basal contacts of upper stratigraphic units in Olduvai Gorge.
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
(2021)
Article
Geosciences, Multidisciplinary
Brian R. Jicha, Walter Hernandez
Summary: The Ilopango caldera in central El Salvador has experienced at least 13 voluminous eruptions in the past two million years, ranging from basalt to rhyolite. While the rhyolitic deposits have been extensively studied, the effusive and monogenetic eruptions at Ilopango have received less attention. This study presents new age and geochemical data that provide insights into the eruptive sequence of Ilopango over almost three million years, revealing two volcanic cycles.
JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH
(2022)
Article
Geochemistry & Geophysics
Augustin Dekoninck, Gilles Ruffet, Julien Baptiste, Robert Wyns, Simon Philippo, Yishen Zhang, Olivier Namur
Summary: This study discusses the hydrothermal formation of romanechite in the Romane`che Mn deposit and the significance of its age by combining ore petrogenesis and 40Ar/39Ar ages. The study confirms the feasibility of romanechite 40Ar/39Ar dating and identifies a period of at least c. 7.6 My of discontinuous hydrothermal activity in the Massif Central.
Article
Geography, Physical
Sander L. Hilgen, Eduard Pop, Shinatria Adhityatama, Tom A. Veldkamp, Harold W. K. Berghuis, Indra Sutisna, Dida Yurnaldi, Guillaume Dupont-Nivet, Tony Reimann, Norbert Nowaczyk, Klaudia F. Kuiper, Wout Krijgsman, Hubert B. Vonhof, Dian Rahayu Ekowati, Gerrit Alink, Ni Luh Gde Dyah Mega Hafsari, Olafianto Drespriputra, Alexander Verpoorte, Remco Bos, Truman Simanjuntak, Bagyo Prasetyo, Josephine C. A. Joordens
Summary: This study aims to establish an accurate age control for the fossils found at the Trinil site in Java, Indonesia. By applying various dating methods and documenting new stratigraphic sections, the researchers identified two distinct fossil-rich channel fills with ages ranging from 830-773 ka to 450 +/- 110 ka. The presence of fossils from different time periods challenges the assumption of a homogeneous biostratigraphic unit at the Trinil site.
QUATERNARY SCIENCE REVIEWS
(2023)
Article
Geosciences, Multidisciplinary
R. Spikings, A. Paul, C. Vallejo, P. Reyes
Summary: The gabbros and ultramafic rocks of the Huargualla Gabbro unit in Ecuador were derived from asthenospheric sources with minor crustal contamination and formed part of the Central Iapetus Magmatic Province. These rocks represent the only igneous record of Iapetus rifting north of the Huancabamba deflection in South America. The age and composition of the Huargualla Gabbro unit is consistent with the reconstruction by Tegner et al. (2019), suggesting juxtaposition of Baltica and northwestern Gondwana within Panotia.
Article
Geology
Katarina Sarinova, Natalia Hudackova, Samuel Rybar, Michal Jamrich, Fred Jourdan, Adam Frew, Celia Mayers, Andrej Ruman, Viktora Subova, Lubomir Sliva
Summary: The analysis of sedimentary fill in the Danube Basin reveals the volcanic activity associated with its middle Miocene formation, and key deposition and subsidence events during the late Badenian period. Additionally, the study highlights the use of index fossils in dating and understanding the geological history of the region.
Article
Geosciences, Multidisciplinary
Rosemeri S. Siviero, Luis A. D. Fernandes, Edinei Koester, Frederic Jourdan
Summary: Geochronological 40Ar/39Ar investigations in the Sao Gabriel Terrane in Brazil, along with previous structural geology studies, provide insights into Neoproterozoic events. The diverse ages of different minerals indicate early structure formation, late tectonic activities, and the impact of cooling rates on metamorphism in the region.
GEOLOGICAL JOURNAL
(2022)
Article
Geochemistry & Geophysics
Alan Levett, Paulo M. Vasconcelos, Michael M. W. Jones, Llew Rintoul, Anat Paz, Emma J. Gagen, Gordon Southam
Summary: The evolution of iron-rich duricrusts in the Serra Sul de Carajas in Brazil plays a key role in enriching and preserving world-class iron ore deposits. Research shows that various exogenous materials are incorporated into secondary cements within the duricrusts, and microorganisms likely contribute to mineral weathering and biomineralization. The mobility of titanium within the duricrusts and the release of ferrous iron during weathering of magnetite-bearing rocks are also important findings.
Article
Geochemistry & Geophysics
Allan Silva Gomes, Paulo Marcos Vasconcelos, Isabela de Oliveira Carmo
Summary: The presence of secondary phases in volcanic rocks and intrusive units may pose challenges for high resolution 40Ar/39Ar geochronology. Acid treatment is used to remove alteration products, but it has minimal impact on the accuracy of age determinations. Effective separation of atmospheric and radiogenic gases can successfully mitigate deleterious effects associated with alteration phases.
Review
Environmental Sciences
Alan Levett, Emma Gagen, Anat Paz, Paulo Vasconcelos, Gordon Southam
Summary: Remediating iron ore mines in Brazil faces a unique challenge of restoring unique rupestrian ecosystems and rare plant species. Developing a substrate similar to iron-rich cap rock and accelerating iron cement formation to stabilize crushed materials, restore hydrology, and revegetate with native species are key elements for successful remediation programs. Understanding biological processes that contribute to canga evolution can lead to environmentally friendly strategies for iron ore mine remediation in the future.
CRITICAL REVIEWS IN ENVIRONMENTAL SCIENCE AND TECHNOLOGY
(2022)
Article
Geology
M. E. Almeida, R. S. C. Nascimento, T. A. Mendes, J. O. S. Santos, M. J. B. Macambira, P. Vasconcelos, S. S. Pinheiro
Summary: The Rio Negro Province in the NW Amazon craton is composed of three domains with different rock types and ages. The province is interpreted as an accretionary orogen formed by a long-lived magmatic arc system, and it has apparent connections with Laurentia and Baltica. The Nd isotope data of the basement rocks provide insights into the mantle sources and crustal contributions.
INTERNATIONAL GEOLOGY REVIEW
(2022)
Article
Geochemistry & Geophysics
Allan Silva Gomes, Paulo Marcos Vasconcelos, Teresa Ubide, Eleonora Maria Gouvea Vasconcellos
Summary: The high-Ti Paranapanema sequence in the Parana Large Igneous Province is characterized by a series of pahoehoe lava flows, some of which contain unique mafic segregation structures. The study of two pegmatite occurrences and their host basalts reveals that the pegmatites are more fractionated and enriched in various elements compared to the enclosing lavas. Additionally, age differences observed in plagioclase phenocrysts from the pegmatites and whole-rock fragments from the enclosing lavas are likely due to hydrothermal alteration rather than differences in crystallization age.
Article
Multidisciplinary Sciences
Matthew R. McCurry, David J. Cantrill, Patrick M. Smith, Robert Beattie, Mary Dettmann, Viktor Baranov, Charles Magee, Jacqueline M. T. Nguyen, Marnie A. Forster, Jack Hinde, Ross Pogson, Helen Wang, Christopher E. Marjo, Paulo Vasconcelos, Michael Frese
Summary: Reduced precipitation in the Miocene caused rainforest ecosystems to contract globally, particularly in Australia where they transformed into shrublands, grasslands, and deserts. The lack of well-preserved fossils has hindered understanding of pre-aridification Australian ecosystems. This study presents an exceptionally well-preserved rainforest biota in New South Wales, Australia, containing a diverse assemblage of microfossils, plants, insects, spiders, and vertebrate remains. These fossils indicate a mesic rainforest surrounding an oxbow lake and suggest shifts in rainforest distributions since the Miocene. The high fidelity of preservation allows for unprecedented insights into Miocene-dominated mesic ecosystems in Australia.
Article
Geochemistry & Geophysics
A. T. Tapu, T. Ubide, P. M. Vasconcelos
Summary: By studying three central volcanoes in eastern Australia, the complexity of magma transport and storage during the waning of hotspot activity is revealed, and it is found that eruptive tempo of volcanism is controlled by mafic influx.
JOURNAL OF PETROLOGY
(2022)
Article
Geochemistry & Geophysics
Zorano Sergio de Souza, Frederico Castro Jobim Vilalva, Elton Luiz Dantas, Jean-Michel Lafon, Francisco Valdir Silveira, Joyce Lorena Oliveira
Summary: Located on the western continental tip of the Fernando de Noronha transform fracture (FNTF) in northeastern Brazil, the Mecejana Phonolitic Province (MPP) underwent a multi-methodological study to understand its characteristics and evolution. The study included field and microscopic characterization, mineral and whole-rock chemistry, and Sr-Nd isotopic analysis. The results indicate a three-stage evolution of the MPP, controlled by the FNTF fracture and the reactivation of deep-rooted Precambrian faults, allowing the emplacement of alkaline magmas.
JOURNAL OF PETROLOGY
(2022)
Article
Geology
Matthew J. Campbell, Nick Mortimer, Gideon Rosenbaum, Charlotte M. Allen, Paulo M. Vasconcelos, Hamish J. Campbell
Summary: We revised and clarified the geology of the Brook Street Terrane in the Takitimu Mountains using airborne magnetic and gamma-ray spectrometric survey, and new age determinations. Our findings include the ages of several plutonic suites and their geological relationships with the Takitimu Subgroup, providing further insights into the Early Permian age nature of the latter.
NEW ZEALAND JOURNAL OF GEOLOGY AND GEOPHYSICS
(2023)
Article
Geochemistry & Geophysics
Tommaso Giovanardi, Paulo Cesar Correa da Costa, Vicente A. V. Girardi, Ricardo K. Weska, Paulo M. Vasconcelos, David S. Thiede, Maurizio Mazzucchelli, Anna Cipriani
Summary: This study investigates the geochemical and geochronological characteristics of basalts from the southern Mato Grosso region of Brazil and compares them with other volcanic rocks from the Paraná Magmatic Province. The results suggest that the Alto Diamantino basalts may represent the northwesternmost expression of the Paraná Magmatic Province, and the origin and formation processes of the magmas are still debated.
Article
Geography, Physical
H. S. Monteiro, P. M. Vasconcelos, K. A. Farley, C. L. Mello, F. T. Conceicao
Summary: Distinctive sediments containing quartz, kaolinite, detrital and authigenic hematite and goethite are present along the Atlantic coast of Brazil. These sediments represent a significant period of erosion and weathering, with strong influence from biologically driven weathering reactions. The ages of detrital and authigenic goethites and hematites suggest that sedimentation occurred between 26-20 million years ago. Furthermore, (U-Th)/He geochronology indicates a period of tropical climate and abundant vegetation dominating the coast of Espirito Santo since the Pliocene.
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
(2022)
Article
Multidisciplinary Sciences
K. A. Farley, K. M. Stack, D. L. Shuster, B. H. N. Horgan, J. A. Hurowitz, J. D. Tarnas, J. I. Simon, V. Z. Sun, E. L. Scheller, K. R. Moore, S. M. McLennan, P. M. Vasconcelos, R. C. Wiens, A. H. Treiman, L. E. Mayhew, O. Beyssac, T. V. Kizovski, N. J. Tosca, K. H. Williford, L. S. Crumpler, L. W. Beegle, J. F. Bell, B. L. Ehlmann, Y. Liu, J. N. Maki, M. E. Schmidt, A. C. Allwood, H. E. F. Amundsen, R. Bhartia, T. Bosak, A. J. Brown, B. C. Clark, A. Cousin, O. Forni, T. S. J. Gabriel, Y. Goreva, S. Gupta, S. -E. Hamran, C. D. K. Herd, K. Hickman-Lewis, J. R. Johnson, L. C. Kah, P. B. Kelemen, K. B. Kinch, L. Mandon, N. Mangold, C. Quantin-Nataf, M. S. Rice, P. S. Russell, S. Sharma, S. Siljestrom, A. Steele, R. Sullivan, M. Wadhwa, B. P. Weiss, A. J. Williams, B. V. Wogsland, P. A. Willis, T. A. Acosta-Maeda, P. Beck, K. Benzerara, S. Bernard, A. S. Burton, E. L. Cardarelli, B. Chide, E. Clave, E. A. Cloutis, B. A. Cohen, A. D. Czaja, V. Debaille, E. Dehouck, A. G. Fairen, D. T. Flannery, S. Z. Fleron, T. Fouchet, J. Frydenvang, B. J. Garczynski, E. F. Gibbons, E. M. Hausrath, A. G. Hayes, J. Henneke, J. L. Jorgensen, E. M. Kelly, J. Lasue, S. Le Mouelic, J. M. Madariaga, S. Maurice, M. Merusi, P. -Y. Meslin, S. M. Milkovich, C. C. Million, R. C. Moeller, J. I. Nunez, A. M. Ollila, G. Paar, D. A. Paige, D. A. K. Pedersen, P. Pilleri, C. Pilorget, P. C. Pinet, J. W. Rice, C. Royer, V. Sautter, M. Schulte, M. A. Sephton, S. K. Sharma, S. F. Sholes, N. Spanovich, M. St. Clair, C. D. Tate, K. Uckert, S. J. VanBommel, A. G. Yanchilina, M. -P. Zorzano
Summary: The Perseverance rover has discovered water-altered igneous rocks in the Jezero crater on Mars and found evidence of brine evaporation in the core samples. These samples may be brought back to Earth for further research.
Article
Geosciences, Multidisciplinary
T. J. Crossingham, T. Ubide, P. M. Vasconcelos, K. M. Knesel
Summary: Small-scale continental basaltic fields can erupt suddenly and bring deep undegassed magmas to the surface rapidly. In this study, the volcanic activity, magma origin, and plumbing system architecture of the Hoy lava field in central Queensland, Australia were investigated and compared with large-scale shield volcanoes. The results show that the volcanism in the Hoy lava field has a long duration of approximately 50 million years and magma storage in the mantle depths, which is different from the relatively short duration and crustal magma storage depths of shield volcanoes.
AUSTRALIAN JOURNAL OF EARTH SCIENCES
(2023)
Article
Geography, Physical
Daniela S. De Campos, Hevelyn S. Monteiro, Paulo M. Vasconcelos, Kenneth A. Farley, Alexandre Christofaro Silva, Pablo Vidal-Torrado
Summary: Lithology plays a crucial role in rock weathering, erosion, and landscape evolution. In a unique geomorphological-lithological-climatic setting in Southern Espinhaco Range, Brazil, resistant quartzites acted as a barrier against erosion and facilitated the formation of deep bauxitic weathering profiles. Recurrent mobilization of aluminium and iron within the profiles was mainly driven by mineral dissolution-reprecipitation mediated by bioturbation and organic species influx.
EARTH SURFACE PROCESSES AND LANDFORMS
(2023)
Article
Geosciences, Multidisciplinary
Dayvison Bruno Cordeiro de Paiva, Frederico Castro Jobim Vilalva, Zorano Sergio de Souza, Marcos Antonio Leite do Nascimento
Summary: The Sao Joao do Sabugi Pluton in northeastern Brazil is a significant occurrence of Ediacaran syn- to post-collisional shoshonitic rocks. The petrography and geochemical modeling suggest that the pluton underwent open-system magmatic differentiation processes, with evidence of crustal assimilation and fractional crystallization.
BRAZILIAN JOURNAL OF GEOLOGY
(2021)
Article
Geosciences, Multidisciplinary
David Dominguez-Santos, Daniel Valderrama, Ahmet Utku Yazgan
Summary: This document presents a study comparing the spectra of large-magnitude seismic records in Chile between 2012 and 2022 with the design spectra of NCh433 and D. S 61. The aim is to determine if Chile's seismic-resistant regulations are updated to the existing reality and propose new design spectra that better represent the seismic activity in Chile during the last decade.
JOURNAL OF SOUTH AMERICAN EARTH SCIENCES
(2024)
Article
Geosciences, Multidisciplinary
Prabhu Palanisamy, Vivek Sivakumar, Priya Velusamy, Logesh Natarajan
Summary: Shoreline changes in the southern coast of Rio de Janeiro, Brazil, were analyzed from 1986 to 2018. The study found that both natural and human factors significantly impact shoreline changes. The findings provided important insights into predicting future shoreline positions and identifying vulnerable regions. Additionally, human activities were found to influence shoreline change models, emphasizing the need for effective management strategies to protect ecosystems and communities.
JOURNAL OF SOUTH AMERICAN EARTH SCIENCES
(2024)
Article
Geosciences, Multidisciplinary
Irina Salgado Bernal, Periyasamy Sivalingam, Armando Martinez Sardina, Michel Manduca Artiles, Maria E. Carballo Valdes, John Pote
Summary: This study investigated the presence of 15 toxic metals in surface sediment in a tropical river ecosystem in Cuba. The results showed that the sediments had higher concentrations of four metals compared to Cuban norms. Various contamination indices were calculated, and correlations analysis revealed the main sources of contamination. The study provides important information for the management of the river and emphasizes the need for metal pollution control and monitoring.
JOURNAL OF SOUTH AMERICAN EARTH SCIENCES
(2024)
Article
Geosciences, Multidisciplinary
Camila Morgan, Eduardo Morgado, Miguel-Angel Parada, Raimundo Brahm, Francisca Mallea-Lillo
Summary: Lanin volcano is a composite volcano in the Andes, which has erupted lava flows with different compositions. The volcano's magma reservoir contains a crystal mush, and the pre-eruptive conditions include temperature, pressure, and oxygen fugacity. Fractional crystallisation has led to the evolution of the magma with different compositions.
JOURNAL OF SOUTH AMERICAN EARTH SCIENCES
(2024)
Article
Geosciences, Multidisciplinary
Benjamin Idini, Sergio Ruiz, Jean-Paul Ampuero, Felipe Leyton, Efrain Rivera
Summary: This study investigates the role of wedge integrity on the frequency content of strong ground motion produced by subduction earthquakes in Northern Chile. The results show that the frequency characteristics of seismic waves vary with hypocentral distance, indicating lateral variations in anelastic attenuation due to the heterogeneous tectonic structure.
JOURNAL OF SOUTH AMERICAN EARTH SCIENCES
(2024)
