Article
Chemistry, Multidisciplinary
Muhammad Qasim, Owais Tayyab, Lin Ding, Javed Iqbal Tanoli, Zahid Imran Bhatti, Muhammad Umar, Hawas Khan, Junaid Ashraf, Ishtiaq Ahmad Khan Jadoon
Summary: This study investigates the age of the post-collisional Chitarwatta Formation in Pakistan using detrital zircon U-Pb dating. The formation is a marine sequence consisting of sandstone, siltstone, and mudstone. The dominant age population of the detrital zircon ranges from 390 Ma to 1100 Ma, with a significant percentage of younger ages between 40 Ma and 120 Ma. The sources of the detritus are suggested to be the Higher Himalaya and Tethyan Himalaya for the older ages, and the Kohistan-Ladakh arc and Karakoram block for the younger ages. It is proposed that the Chitarwatta Formation received detritus from the northern sources through the Indus drainage system.
APPLIED SCIENCES-BASEL
(2023)
Article
Geochemistry & Geophysics
Yimin Tian, Robert A. Spicer, Jian Huang, Zhekun Zhou, Tao Su, Mike Widdowson, Linbo Jia, Shihu Li, Wenjian Wu, Li Xue, Penghui Luo, Shitao Zhang
Summary: The sedimentary basins of Yunnan in Southwest China provide detailed records of Cenozoic paleoenvironmental change, important for understanding the development of modern floral diversity in the region. High resolution U-Pb dating has allowed researchers to redefine the age of fossil-bearing strata in the Wenshan Basin, indicating a significantly greater antiquity than previously recognized. This age revision highlights late Eocene-early Oligocene regional tectonism and suggests a Paleogene origin for Asia's high plant diversity.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
Article
Geochemistry & Geophysics
Juan F. Albano, Laura Lombardi, Emilio Rocha, Jonathan Tobal, Julie C. Fosdick, Andrea L. Stevens Goddard, Rebecca A. VanderLeest, Miguel Ramos, Pablo Giampaoli, Pedro Kress, Fernanda Raggio
Summary: We conducted a multidisciplinary study to unravel the evolution of the fold-thrust belt and foreland basin sedimentation in the Austral-Magallanes basin. Using U-Pb geochronology and provenance analysis, we calculated maximum depositional ages and analyzed regional variations in provenance. Our findings contribute to the understanding of the geodynamic framework and timing variations in the South Patagonian Andes.
Article
Geochemistry & Geophysics
Laura Gemmrich, Lisard Torro, Joan Carles Melgarejo, Oscar Laurent, Jean Vallance, Cyril Chelle-Michou, Thierry P. A. Sempere
Summary: The Bolivian tin belt is known for its Sn, W, Ag, and base metal deposits, with cassiterite serving as a useful geological tracer mineral. New U-Pb dating of cassiterite indicates at least two separate events of Sn mineralization in the region, triggered by major magmatic episodes and high heat flow into the crust. The composition of hydrothermal cassiterite varies based on distance to causative intrusive complexes, with potential for inclusion of critical elements like In and Ga.
MINERALIUM DEPOSITA
(2021)
Article
Geosciences, Multidisciplinary
Hugo K. H. Olierook, Christopher L. Kirkland, Milo Barham, Matthew L. Daggitt, Julie Hollis, Michael Hartnady
Summary: The study presents a technique to rapidly extract meaningful core model ages from core-rim mixtures, along with a Python-based program for easy application of this approach. The efficacy of the technique is demonstrated on a detrital sample from East Greenland, recovering dates of detrital cores from core-rim mixtures. Caution is advised against using this technique without checking the appropriateness of the underlying assumptions, and chemical means are provided for evaluating the assumptions.
Article
Geology
Marta Roige, David Gomez-Gras, Daniel F. Stockli, Antonio Teixell, Salvador Boya, Miquel Poyatos-More
Summary: This study investigates the provenance evolution of the clastic deposits in the Jaca basin in the southern Pyrenees from the mid Eocene to early Miocene. It reveals a shift in the source area from the Variscan to Cadomian signature. The integration of detrital zircon U/Pb data with sandstone petrography improves the resolution of the source-area shifts and the understanding of sediment recycling during foreland evolution.
SEDIMENTARY GEOLOGY
(2023)
Article
Geosciences, Multidisciplinary
Chengfu Lyu, Chao Li, Guojun Chen, Gongcheng Zhang, Ming Ma, Ying Zhang, Zhaotong Sun, Qianshan Zhou
Summary: The study utilized zircon U-Pb ages to investigate the provenance of Upper Oligocene to Upper Miocene sandstones in the western Qiongdongnan Basin. It was found that the sediments of the Lingshui Formation may have originated from the Red River system, while the Sanya Formation was mainly from Hainan Island and the Huangliu Formation's provenance was the Red River system.
MARINE AND PETROLEUM GEOLOGY
(2021)
Article
Geochemistry & Geophysics
Federico E. Martos, Maximiliano Naipauer, Lucas M. Fennell, Eliana Acevedo, Natalia Hauser, Andres Folguera
Summary: This study focuses on the early synorogenic deposits in the Neogene Penitentes basin in the southern Central Andes, and provides new insights into the genesis and evolution of this basin through sedimentological, geochronological, and structural analyses. The findings reveal the role of uplift and exhumation of the Principal and Frontal cordilleras in controlling the sediment sources and deposition patterns in the Penitentes basin.
Article
Geochemistry & Geophysics
Sean P. Gaynor, Melissa Ruiz, Urs Schaltegger
Summary: This study presents high-precision isotope dilution-thermal ionization mass spectrometry (ID-TIMS) U-Pb zircon data from the Carboniferous Punteglias granodiorite in Switzerland. The results show that the zircon crystals have a mixture of two different age components, and the crystallization age of the zircon is determined to be 335.479 +/- 0.041 Ma. Additionally, pretreating the zircon samples with physical and chemical abrasion reduces age dispersion and allows for a more accurate determination of the initial magmatic domains. The high analytical precision of this study is crucial for correctly interpreting complex age spectra.
Article
Chemistry, Analytical
Jia-Long Hao, Wei Yang, Sen Hu, Rui-ying Li, Jiang-Long Ji, Hitesh G. Changela, Yang-Ting Lin
Summary: This paper presents a novel Pb-Pb and U-Pb analytical method at a sub-micron scale using a NanoSIMS with a new RF ion source. The technique allows for high spatial resolution but may introduce depth effects, requiring adjustments in the scan area to eliminate mass fractionation. Results from zircon and lunar samples are in good agreement with reference ages within analytical uncertainties.
JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY
(2021)
Article
Geosciences, Multidisciplinary
Jian Zhang, Jian Wang, Bo Zheng, Qingyi Sheng, Hengye Wei, Lijun Shen, Shaoyun Xiong, Ahmed Mansour
Summary: This study reassigns the depositional age of the dolomite in the palaeo-reservoirs in the south Qiangtang depression through micro-palaeontological identification and in-situ U-Pb isotope dating analysis. The high-resolution diagenetic time framework reveals a possible link between dolomitization and hydrocarbon accumulation in basin-scale fluid-flow events. The findings challenge previous interpretations and provide important insights for oil and gas exploration in the Qiangtang basin.
MARINE AND PETROLEUM GEOLOGY
(2023)
Article
Geology
Kyle P. Larson, John M. Cottle, Alfredo Camacho, Stephen Piercey, Djordje Grujic
Summary: The Khumbu region in Nepal is home to large leucogranite bodies that crystallized around 19 and 17 million years ago, with significant inherited age components. The rapid cooling of these leucogranites may have a genetic relationship with extension processes, as indicated by the timing of motion along the Qomolangma detachment. Cooling after argon closure was slower and the rapid cooling phase may have been ephemeral.
INTERNATIONAL GEOLOGY REVIEW
(2022)
Article
Geosciences, Multidisciplinary
Sebastian J. Cao, Pablo J. Torres Carbonell, Sofia Bordese, Juan P. Lovecchio
Summary: This paper discusses the limitations of detrital zircon geochronology and the need for cautious treatment of isotopic ages in determining sedimentary rock depositional ages. Using the Lapataia Formation in the Fuegian Andes of southernmost South America as a case study, a comprehensive analysis aided by geological constraints accurately evaluates the stratigraphic age and provenance of the formation.
Article
Spectroscopy
Ya-Nan Yang, Miaohong He, Yan-Qiang Zhang, Yi-Gang Xu
Summary: NanoSIMS is a powerful instrument for Pb/Pb and U/Pb dating at the submicron scale. This study demonstrates that using O-16(2)- as the primary beam species and an RF oxygen ion source can significantly improve the precision and accuracy of the dating method.
ATOMIC SPECTROSCOPY
(2022)
Article
Geosciences, Multidisciplinary
Manuel Lopez, Florencia Milanese, Leandro D'Elia, Andres Bilmes, Joaquin Bucher, Rodrigo N. Feo, Micaela Garcia, Manuel Calvo-Rathert, Augusto Rapalini, Juan R. Franzese
Summary: The Patagonian Andean foreland system preserves a well-preserved fluvial record from the Miocene, which was deposited under the influence of Andean uplift and regional climate change. The sedimentary patterns in the basin suggest variations in sediment flux caused by different external forcing mechanisms, and the concept of basin equilibrium time can help decouple these forcings.
Article
Multidisciplinary Sciences
Marcelo M. Rivadeneira, Sven N. Nielsen
Article
Geology
Rodrigo M. Vega, Mauricio Mella, Sven N. Nielsen, Mario Pino
Correction
Multidisciplinary Sciences
Marcelo M. Rivadeneira, Sven N. Nielsen
Article
Geology
Rodrigo M. Vega, Mauricio Mella, Sven N. Nielsen, Mario Pino
Article
Multidisciplinary Sciences
Martin Chavez Hoffmeister, Jorge D. Carrillo Briceno, Sven N. Nielsen
Article
Paleontology
Stephen K. Donovan, Sven N. Nielsen, J. Velez-Juarbe, Roger W. Portell
SWISS JOURNAL OF PALAEONTOLOGY
(2019)
Article
Paleontology
Leonardo Perez-Barria, Sven N. Nielsen
JOURNAL OF PALEONTOLOGY
(2020)
Article
Geosciences, Multidisciplinary
Jaime A. Villafana, Sven N. Nielsen, Stefanie Klug, Juergen Kriwet
JOURNAL OF SOUTH AMERICAN EARTH SCIENCES
(2019)
Article
Paleontology
Sven N. Nielsen, Francisca A. Ampuero
Article
Paleontology
Pablo Oyanadel-Urbina, Carlos De Gracia, Jorge D. Carrillo-Briceno, Sven N. Nielsen, Hector Flores, Victor Casteletto, Juergen Kriwet, Marcelo M. Rivadeneira, Jaime A. Villafana
Summary: Despite being rich in marine fossil vertebrates, the Bahia Inglesa Formation along the Pacific coast of Chile had not been thoroughly studied for bony fishes until this research was conducted. By revising historical collections, 27 fossil remains of bony fishes were described, revealing new fossil records for various taxa. The study indicates that the fish fauna from the Bahia Inglesa Formation likely lived at depths ranging from 98 to 382 meters, with a mean depth of 252 meters, and shows low taxonomic similarity with other Neogene geological units in the southeast Pacific Ocean.
Article
Paleontology
Werner W. Schwarzhans, Sven N. Nielsen
Summary: This study describes a rich otolith assemblage obtained from fifteen early Miocene outcrop locations along the Chilean coast, identifying 67 species, with 27 new to science. The findings enrich the understanding of the fish fauna in the Pacific side of South America and indicate differences from previously known fish associations.
SWISS JOURNAL OF PALAEONTOLOGY
(2021)
Article
Biology
Aldo Benites-Palomino, Ana M. Valenzuela-Toro, Constanza Figueroa-Bravo, Rafael M. Varas-Malca, Sven N. Nielsen, Carolina Simon Gutstein, Jorge D. Carrillo-Biceno
Summary: This study describes a new marine mammal assemblage from the upper Pliocene in central Chile, providing new information about the timing for the establishment of modern diversity and distribution of seals in the Southern Hemisphere.
HISTORICAL BIOLOGY
(2022)
Article
Environmental Sciences
Marcelo M. Rivadeneira, Sven N. Nielsen
Summary: The Humboldt Current Marine Ecosystem (HCE) is facing a significant threat to marine biodiversity, particularly from overfishing. This study uses the Quaternary fossil record along the HCE coast to assess the impact of human activities on mollusk diversity. The results show that modern mollusk assemblages have undergone drastic alterations compared to fossil counterparts, with significant changes in species composition and a reduction in the relative abundance of exploited species. This study highlights the long-term disruption of species composition and the severe disturbance caused by overfishing, providing a foundation for understanding the impacts of anthropogenic stressors in the HCE.
FRONTIERS IN MARINE SCIENCE
(2022)
Article
Biodiversity Conservation
Mariana Grossmann, Sven N. Nielsen, Marcelo M. Rivadeneira, Nelson Valdivia
Summary: Understanding latitudinal variations in biodiversity is essential for biogeography. In the coast of the Southeast Pacific, it is observed that several taxa exhibit increasing species numbers from lower to higher latitudes. This phenomenon can be explained by the presence of fjords formed during glaciations, which increased the diversity of available biotopes and allowed higher diversity in high latitudes. This research focuses on analyzing latitudinal patterns of functional diversity in the fossil record before the formation of fjords in order to assess this hypothesis.
Article
Paleontology
Jocelyn Rojas, Sven N. Nielsen
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)