Article
Geochemistry & Geophysics
Yiming Ma, Qiang Wang, Huapei Wang, Bo Wan, Shihong Zhang, Chenglong Deng, Dongyu Zheng, Qiang Ren, Tianshui Yang, Dan Wu, Di Zou, Jun Wang, Xiao Liu, Zhiqiang Kang, Wei Dan, Fei Han, Mark J. Dekkers
Summary: The drift history of the Lhasa terrane from Gondwana to Asia is crucial for understanding the Tethys evolution and true polar wander. This study provides new paleomagnetic evidence that the Lhasa terrane was located at around 8 degrees S around 180 Ma and suggests a significant acceleration in its northward motion from 220-170 Ma.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Geochemistry & Geophysics
B. Chiasera, T. O. Rooney, I. D. Bastow, G. Yirgu, E. B. Grosfils, D. Ayalew, P. Mohr, J. Zimbelman, M. Ramsey
Summary: The study of magmatic activity in the Galema range in the northern Main Ethiopian Rift reveals evidence of magma ponding during ascent, indicating relatively thick lithosphere during the early magmatic rifting. Contrasting modeling approaches show different melting conditions and temperatures, suggesting a thermo-mechanical boundary to ascent. These results have important implications for late-stage decompression melting prior to the onset of seafloor spreading.
Article
Geochemistry & Geophysics
Charlotte Fredriksson, Victoria Pease
Summary: This study investigates the geological structure of northern Alaska and identifies the uplift process of the Brooks Range during the Early Cretaceous. By analyzing the age, chemistry, and isotopic data of igneous clasts and samples, it is concluded that the igneous clasts mainly originate from the Brooks Range ophiolite. A revised tectonic model is proposed that integrates the formation of Late Triassic island arc with the evolution of the Brooks Range ophiolite.
Article
Geosciences, Multidisciplinary
Wubamlak Nigussie, Kevin Mickus, Derek Keir, Abera Alemu, Yoseph Muhabaw, Ameha A. Muluneh, Esubalew Yehualaw, Zelalem Demissie
Summary: In magma-rich continental rifts, extension is commonly localized as dike injection in discrete magmatic segments which appear from surface geology to mimic the along-axis segmentation of ocean ridges. The subsurface morphology of these zones of localized magma injection remains unclear, including their depth range and relationship with tectonic faulting. Using gravity data, the study of the Main Ethiopian Rift reveals discrete Bouguer gravity highs in the centers of right-stepping magmatic segments, suggesting the presence of mafic intrusions. The study also suggests strong along-axis variations in deformation mechanism, with magma injection accommodating extension at the segment centers and faulting dominating towards the segment ends. Rift margin volcanic zones are inferred near the rift flanks.
FRONTIERS IN EARTH SCIENCE
(2023)
Article
Geography, Physical
Hao Wu, Jian-Jun Fan, Zi-Qi Jiang, Yu-Jie Hao, An-Bo Luo
Summary: The study presents new data of silicic igneous rocks in the Shiquanhe and Guchang areas, indicating derivation from magmas formed by partial melting of ancient crustal metagraywackes. The results suggest the presence of a Late Jurassic-Early Cretaceous magmatic belt in northern Tibet, recording the magmatic evolution from forearc to continental arc settings.
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
(2021)
Article
Geosciences, Multidisciplinary
Francesco Mazzarini, Ilaria Isola
Summary: Tectonic inheritance plays a key role in determining the location and development of rift segments in the East African Rift System. In the Chyulu Hills volcanic field in southeast Kenya, volcanic activity is influenced by a Proterozoic crustal-scale shear zone, with vent density and clustering changing along the ridge in a pattern mirroring the age of volcanism. These findings suggest a focused magma injection into the continental lithosphere along inherited crustal structures.
JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH
(2021)
Article
Geochemistry & Geophysics
Masoud Mirzaei, Bernard A. Housen, Russell F. Burmester, Brady Z. Foreman
Summary: Two apparent polar wander paths for North America diverge during the Jurassic, with discrepancy attributed to inclination error from deposition and compaction. New paleomagnetic results from sedimentary units in east-central New Mexico validate the lower-latitude APWP, suggesting another explanation is needed for the discrepancy.
Article
Geosciences, Multidisciplinary
Gaurav Hazarika, Bibhuti Gogoi
Summary: The Kathalguri Pluton in Northeast India shows evidence of Pan-African bimodal magmatism and the important role of magma mixing in its evolution.
INTERNATIONAL JOURNAL OF EARTH SCIENCES
(2023)
Article
Geosciences, Multidisciplinary
Carlos M. Gonzalez-Leon, Michelle Vazquez-Salazar, Teresita Sanchez Navarro, Luigi A. Solari, Jonathan A. Nourse, Rafael Del Rio-Salas, Rufino Lozano-Santacruz, Ofelia Perez Arvizu, Juan Carlos Valenzuela Chacon
Summary: This work reports on the geology and U-Pb LA-ICPMS zircon geochronology of a crustal section that is part of the Jurassic magmatic arc in the Magdalena quadrangle of north-central Sonora, Mexico. The study found that the rock succession in the area was affected by Late Cretaceous shortening, intruded by early Tertiary granitoids, and further exhumed in the early Miocene. The ages obtained indicate that the arc in the study area developed from ca. 176 to 158 Ma, encompassing a 17 m.y. interval of magmatism and associated sedimentation.
JOURNAL OF SOUTH AMERICAN EARTH SCIENCES
(2021)
Article
Geosciences, Multidisciplinary
Kitso N. Matende, Estella Atekwana, Kevin Mickus, Mohamed G. Abdelsalam, Eliot A. Atekwana, Rob Evans, Victor N. Nyalugwe, Luelseged Emishaw
Summary: This study used aeromagnetic, satellite gravity, and ground gravity data to image the thermal and crustal structures beneath the LLL rift in southeastern Zambia. The results indicate the presence of a large magnetized body and a crust approximately 45 km thick beneath the rift. Analysis of ground gravity data suggests the presence of a large mafic body beneath the crust.
JOURNAL OF AFRICAN EARTH SCIENCES
(2021)
Article
Geology
Faouziya Haissen, Mohamed Najib Zaghloul, Yildirim Dilek, Oriol Gimeno-Vives, Geoffroy Mohn, Aitor Cambeses, Dominique Frizon de Lamotte, Valerie Bosse
Summary: The study revealed that the Lower Jurassic mafic rock suites in the Rif orogenic belt in northern Morocco are part of the Central Atlantic Magmatic Province and formed around 200 million years ago. These rocks exhibit alkaline characteristics and high TiO2 content, originating from partial melting of the subcontinental lithospheric mantle.
JOURNAL OF GEOLOGY
(2021)
Article
Geosciences, Multidisciplinary
A. M. Larin, A. B. Kotov, E. B. Salnikova, V. P. Kovach, Yu Plotkina, T. M. Skovitina
Summary: The granitoids of the Uda complex were formed in the Early Cretaceous, with an initial magma sourced from a mixture of Early Precambrian lower crust and mantle, where the crustal component dominated. They likely represent the eastern end of the Udsko-Zeya (Stanovoy) post-collision magmatic belt, stretching for over 1000 km along the southern framing of the Siberian craton parallel to the Mongol-Okhotsk suture zone, connecting different tectonic blocks of the northeastern part of the Central Asian fold belt.
DOKLADY EARTH SCIENCES
(2021)
Article
Geosciences, Multidisciplinary
Cornelia Rasmussen, Roland Mundil, Randall B. Irmis, Dominique Geisler, George E. Gehrels, Paul E. Olsen, Dennis Kent, Christopher Lepre, Sean T. Kinney, John W. Geissman, William G. Parker
Summary: The Upper Triassic Chinle Formation in Petrified Forest National Park, Arizona, is a significant non-marine archive of biotic and environmental changes, with new age models suggesting a mid-Norian event rather than correlation to the Carnian-Norian boundary. By combining detrital CA-ID-TIMS ages with magnetostratigraphic data, two feasible age model solutions have been proposed, showing the challenges and powers of integrating different dating methods for complex sedimentary sequences.
GEOLOGICAL SOCIETY OF AMERICA BULLETIN
(2021)
Article
Geosciences, Multidisciplinary
Huapei Wang, Dennis Kent
Summary: This study developed an experimental approach to monitor the thermal alterations that may occur during laboratory heating to specimens used in Thellier-series paleointensity experiments, addressing the issue of incomplete detection of thermal alterations.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geosciences, Multidisciplinary
Dennis V. Kent, Paul E. Olsen, Giovanni Muttoni, Mohammed Et-Touhami
Summary: The Ikakern Formation in Morocco's Argana basin is a significant basal sedimentary unit, providing valuable paleomagnetic information and indicating a Late Permian age post-Kiaman event. Its magnetic pole, consistent with similar age poles from various continents, confirms the existence of a Pangea A configuration during the Late Permian.
Article
Multidisciplinary Sciences
Christopher J. Lepre, Paul E. Olsen
Summary: The study validates pigmentary hematite as a proxy indicator for the Late Triassic environment through analyzing a red bed sequence in Arizona. The results show the evolving pattern of the Late Triassic monsoon, a long-term rise in aridity starting around 215 Ma, and increased oscillatory climate change at around 213 Ma. These changes are attributed to the drift of the Colorado Plateau northward as part of Laurentia and fluctuating CO2 levels.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Geology
Calum P. Fox, Jessica H. Whiteside, Paul E. Olsen, Xingqian Cui, Roger E. Summons, Erdem Idiz, Kliti Grice
Summary: High-resolution biomarker and compound-specific isotope distributions, coupled with the degradation of calcareous fossil remnants, reveal that intensive euxinia and decalcification driven by Central Atlantic magmatic province activity formed a two-pronged kill mechanism at the end-Triassic mass extinction.
Article
Paleontology
Lars B. Clemmenseno, Sofie Lindstrom, Octavio Manuse, Malte Mau, Jesper Milano, Dennis Kent
Summary: The Kap Stewart Group in central East Greenland, traditionally considered a continental unit, is now believed to have experienced marine influence based on new findings of plesiosaur bone remains. The bonebearing sandstone layer in the Rhaetelv Formation of the group can be dated back to the Hettangian period, around 200 million years ago. This discovery provides a numerical age constraint for a previously poorly dated succession.
Article
Geography, Physical
D. Kent, G. Muttoni
Summary: The study reveals that global surface albedo remained almost constant during the Late Cretaceous and Cenozoic periods until it increased by 30% with the onset of the Late Cenozoic Ice Age. This shift reflects global cooling caused by reductions in greenhouse gases below a critical threshold, possibly due to accelerated CO2 weathering consumption of continental mafic rocks in tropical humid regions. The role of cloud cover in planetary albedo remains unclear, but it may be speculated to be influenced by the increasing land bias between the northern and southern hemispheres over the Cenozoic.
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
(2022)
Article
Geochemistry & Geophysics
Douglas G. Beaver, Dennis Kent, Ian W. D. Dalziel
Summary: Paleomagnetic analysis of South Georgia suggests a 27.2-degree counterclockwise rotation and a 10.5-degree northward tilting since the Late Cretaceous, supporting the idea that South Georgia is a continuation of the Rocas Verdes marginal basin system.
Article
Geochemistry & Geophysics
C. P. Fox, J. H. Whiteside, P. E. Olsen, K. Grice
Summary: This study investigates the fossil record of key sections in the southwestern UK and finds that there was little evidence of large-scale wildfires during the end-Triassic mass extinction. Instead, the region was affected by acid rain and soil erosion. The study also reveals that the existing carbon isotope anomaly records do not accurately reflect the activity of Large Igneous Provinces (LIPs), but rather the increased input of terrestrial plant material. These findings suggest that multiple factors influenced the terrestrial phase of the end-Triassic mass extinction in the southwestern UK.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Multidisciplinary Sciences
Malte Mau, Dennis Kent, Lars B. Clemmensen
Summary: Sedimentological records are the only accessible archives for studying Earth's orbital variations in the distant geological past. A study comparing the climate response to orbital variations in a Late Triassic midlatitude temperate setting and a tropical low paleolatitude setting reveals antiphasing between the two, which has implications for global correlation of geological records.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Geosciences, Multidisciplinary
J. E. T. Channell, G. Muttoni, D. V. Kent
Summary: The study examines the relationship between the continental margins surrounding the Adriatic Sea and Africa, as well as the arguments surrounding the Mediterranean Mesozoic paleogeography. The authors propose a new model that suggests a sinistral strike-slip fault system existed between Adria and Africa during the Middle Jurassic, contradicting the existence of the Mesogea ocean. The consistency of paleomagnetic data supports the existence of Pangea B in the Early Permian, transforming into Pangea A by the Late Permian.
EARTH-SCIENCE REVIEWS
(2022)
Article
Multidisciplinary Sciences
Paul Olsen, Jingeng Sha, Yanan Fang, Clara Chang, Jessica H. Whiteside, Sean Kinney, Hans-Dieter Sues, Dennis Kent, Morgan Schaller, Vivi Vajda
Summary: Abundant lake ice-rafted debris in Late Triassic and earliest Jurassic strata of the Junggar Basin of northwestern China indicates that freezing winter temperatures typified the forested Arctic, despite high levels of atmospheric CO2. Non-avian dinosaurs were primitively insulated, enabling them to access rich Arctic vegetation even under freezing winter conditions. Transient volcanic winters led to the end-Triassic mass extinction on land, while insulated dinosaurs not only survived but also rapidly expanded in the Jurassic.
Article
Paleontology
Lars B. Clemmenseno, Sofie Lindstrom, Octavio Manuse, Malte Mau, Jesper Milano, Dennis Kent
Summary: The discovery of plesiosaur bone remains in the Rhaetelv Formation of the Kap Stewart Group in central East Greenland suggests a period of marine influence. By dating the bone-bearing sandstone bed to approximately 200 million years ago, this study provides the first numerical age constraint for this previously poorly dated succession.