Article
Geology
Brennan O'Connell, Rebecca J. Dorsey, Stephen T. Hasiotis, Ashleigh V. S. Hood
Summary: This study presents sedimentological and ichnological data from the Bouse Formation, which accumulated during regional transgression near the north end of the ancestral Gulf of California. The study provides evidence for a late Miocene to early Pliocene humid climate in southwestern North America, with significant facies variability at different scales documented in mixed carbonate-siliciclastic deposits.
Review
Geography, Physical
Carol A. Hill
Summary: The purpose of this paper is to study the geomorphic evolution of Glen Canyon, Upper Colorado River Corridor, and Grand Canyon in order to address the mystery of why the Colorado River did not reach the mouth of Grand Canyon until 5.5 million years ago and how it crossed the Kaibab arch high. The paper reviews geologic investigations in the Glen Canyon area, explains the importance of a paleo-Colorado River constrained within a lake or a chain of lakes for the river to reach Grand Canyon at 5.5 million years ago, and proposes different models to explain the incision rates in Marble Canyon, Glen Canyon, and central Colorado Plateau. The paper also discusses the possibility of a Miocene lake or chain of lakes along Glen Canyon and Upper Colorado River Corridor and compares different models for the river's crossing of the Kaibab arch.
Article
Geography, Physical
F. Pilade, I. Vasiliev, D. Birgel, F. Dela Pierre, M. Natalicchio, A. Mancini, G. Carnevale, R. Gennari
Summary: This study uses alkenone-based proxies and other data to reconstruct surface water temperatures and paleoenvironmental conditions in the Mediterranean basin during the late Miocene to early Pliocene period. The results suggest that the Mediterranean basin gradually returned to marine conditions before the end of the late Miocene, and fully marine conditions were established in the early Pliocene. This highlights the importance of alkenone-based proxies in environmental reconstruction, especially when fossil records of primary producers are limited.
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
(2023)
Article
Oceanography
Noel Carbajal, Jose Tuxpan Vargas, Juan Heberto Gavino Rodriguez, Yovani Montano Ley, David Alberto Salas de Leon
Summary: The translation discusses the formation of sandbanks in the Colorado River Delta due to tidal currents and sea-bottom sediment interactions, as well as the presence of Kelvin-Helmholtz instabilities caused by velocity shears. It also mentions the observation of sandbanks in various seas and the use of satellite images to explain the generation and identification of these instabilities.
Article
Multidisciplinary Sciences
Ahmed Gad, Osman Abdelghany, Hasan Arman, Bahaa Mahmoud, Ala Aldahan, Safwan Paramban, Mahmoud Abu Saima
Summary: This study focuses on the subsurface Miocene evaporite facies in Abu Dhabi for the first time. Petrographic, mineralogical, and geochemical investigations were conducted on 45 evaporite rock samples to determine their origin and age. The results show that the samples are predominantly composed of secondary gypsum with minor amounts of other minerals. The stable isotope analysis suggests a Miocene marine sulfate origin with a range of 21.12-15.91 Ma.
Article
Geosciences, Multidisciplinary
Jon E. Spencer, Kurt N. Constenius, David L. Dettman, Kenneth J. Domanik
Summary: The cause of Cenozoic uplift of the Colorado Plateau remains one of the largest problems in Cordilleran tectonics. The study suggests that the laminated structure of the Pliocene Bouse Formation carbonate member shows seasonal rather than tidal sedimentation characteristics, indicating a lacustrine origin instead of an estuarine one.
Article
Geochemistry & Geophysics
Iuliana Vasiliev, Marius Stoica, Arjen Grothe, Sergei Lazarev, Dan Valentin Palcu, Christiaan van Baak, Arjan De Leeuw, Francesca Sangiorgi, Gert-Jan Reichart, Gareth R. Davies, Wout Krijgsman
Summary: The Dacian Basin uniquely recorded late Miocene hydrological changes and connectivity from the latest Tortonian to the early Pleistocene, with differences in strontium isotope ratios providing insights into depositional environments and faunal dispersal in Central Eurasia's mega-lake Paratethys.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2021)
Article
Geosciences, Multidisciplinary
Kata Molnar, Pierre Lahitte, Stephane Dibacto, Zsolt Benko, Samuele Agostini, Boglarka Donczo, Artur Ionescu, Ivica Milevski, Zita Szikszai, Zsofia Kertesz, Marjan Temovski
Summary: Late Miocene to Pleistocene volcanic activity in the Vardar zone in North Macedonia is associated with the tectonic evolution of the South Balkan extensional system and the northern part of the Aegean extensional regime. The study focused on three volcanic centers with sparse geochronological and geochemical data, revealing that the onset of scattered potassic to ultrapotassic volcanism in the region occurred around 8.0 million years ago. This research provides insights into the evolution of sedimentary basins and the metasomatism of the lithospheric mantle over time.
INTERNATIONAL JOURNAL OF EARTH SCIENCES
(2022)
Article
Environmental Sciences
Araceli Molina-Garcia, Jaqueline Garcia-Hernandez, Martin Federico Soto-Jimenez, Federico Paez-Osuna, Martin Enrique Jara-Marini
Summary: The study examined the biomagnification of Hg and Se in a coastal lagoon in the eastern central Gulf of California using nitrogen stable isotope analysis. The results showed a significant accumulation of both elements in the food web, with no linear correlations between the Se:Hg ratios and trophic levels. The excess of Se among organism groups indicates that it is not a limiting factor for the detoxification of Hg.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2021)
Article
Multidisciplinary Sciences
Alicia Van Ham-Meert, Aoife Daly
Summary: Dendrochronology is used to date and identify the origin of timber, but reference datasets may include timber from non-local sources. In this study, Sr isotopic analysis was applied to timber from three historic buildings in Jutland, Denmark, to improve provenance identification. The results showed that some timbers were imported from Sweden, while others were local or from south Norway. The combination of dendrochronology and Sr isotopic analysis provided a more detailed interpretation of the origin of non-Danish timbers.
Article
Geosciences, Multidisciplinary
Miao-Yan Zhang, Lu-Lu Hao, Qiang Wang, Yue Qi, Lin Ma
Summary: Adakitic rocks at continental collisional zones have important implications for understanding the mechanism of crustal reworking. The genesis of adakitic rocks in the western Lhasa block remains highly debated, hindering our understanding of crustal reworking in the whole Lhasa block. The Sailipu trachyandesites in the western Lhasa block show characteristics of adakitic rocks and were likely generated by the interaction between the juvenile lower crust and underplated ultrapotassic magmas.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Geosciences, Multidisciplinary
M. E. Gastaldello, C. Agnini, T. Westerhold, A. J. Drury, R. Sutherland, M. K. Drake, A. R. Lam, G. R. Dickens, E. Dallanave, S. Burns, L. Alegret
Summary: This study focuses on a marine drilling site in the Tasman Sea during the Late Miocene-Early Pliocene Biogenic Bloom. An age model was established using various methods, and it was found that there were changes in deep water oxygen concentrations and benthic foraminiferal assemblages, possibly related to seasonal phytoplankton blooms. Additionally, a regional change in paleoceanography was inferred around 6.7 Ma. Therefore, highly resolved studies are crucial for understanding this complex and multiphase phenomenon, as well as the local, regional, and global impacts.
PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY
(2023)
Article
Geosciences, Multidisciplinary
Rebecca J. Dorsey, Brennan O'Connell, Kevin K. Gardner, Mindy B. Homan, Scott E. K. Bennett, Jacob O. Thacker, Michael H. Darin
Summary: The study reveals that the southern Blythe Basin formed in a broad transtensional sag basin between the dextral Laguna fault system and the Cibola and Big Maria fault zones. Analysis of fault zones indicates a complex geological movement in the region over the past 5 million years, related to the Pacific-North America plate boundary shear.
Article
Geochemistry & Geophysics
Jorge Antonio Puente Huerta, Mario Gonzalez-Escobar, Joann M. Stock
Summary: The Altar basin, located in the northern Gulf of California and Salton Trough, is a segmented marginal basin formed during the Late Miocene-Early Pliocene oblique rift system. This study uses processed seismic data to characterize the tectonostratigraphic features of the basin, including deep structure, faults controlling subsidence, and accumulation of deltaic deposits. The results show the presence of NW-trending faults, three major seismic reflectors defining three units, and correlations with the Bouse Formation in SW Arizona and SE California. The study also suggests that the Altar fault is continuous with the Dunas fault in SE California.
PURE AND APPLIED GEOPHYSICS
(2022)
Article
Geosciences, Multidisciplinary
Skyler P. Mavor, Scott E. K. Bennett, Ryan S. Crow, John S. Singleton, Victoria Langenheim, Daniel Stockli, Mark Stelten, Timothy A. Brickey, Paul J. Umhoefer, L. Sue Beard
Summary: In the vicinity of Blythe, California, there are numerous NW-striking faults that have been interpreted as either normal faults related to Middle Miocene extension or strike-slip faults related to Late Miocene to Pliocene dextral shear. Through kinematic data analysis and dating of rocks, it is revealed that these faults primarily occurred during the Late Miocene dextral oblique faulting stage, representing a transitional phase from Early to Middle Miocene extension to subsequent NW-directed dextral shear. The study also estimates a total of 11-38 km of dextral slip in a 50-km-wide zone from the Palen to Riverside mountains.