Results 81 to 90 of about 8,027 (255)

Seawater redox variations during the deposition of the Kimmeridge Clay Formation, United Kingdom (Upper Jurassic): evidence from molybdenum isotopes and trace metal ratios [PDF]

open access: yes, 2010
The Kimmeridge Clay Formation (KCF) and its equivalents worldwide represent one of the most prolonged periods of organic carbon accumulation of the Mesozoic.
Abbink   +81 more
core   +1 more source

Mid‐Ocean Ridge (MOR) Ash Dispersal on Axial Seamount, Juan de Fuca Ridge

open access: yesGeochemistry, Geophysics, Geosystems, Volume 26, Issue 9, September 2025.
Abstract Rare eruption of primitive normal mid‐ocean ridge basalt (N‐MORB) magma (∼9.5 wt% MgO) on the summit of Axial Seamount generated abundant ash that was dispersed for several km. The unique geochemical signature of this ash deposit is distinct from otherwise typical MORB with more evolved compositions. As such, it is a key marker bed that can be
Ryan A. Portner   +5 more
wiley   +1 more source

Facies analysis, sequence stratigraphy and chemostratigraphy of the Sete Lagoas Formation (Bambui Group), northern Minas Gerais State, Brazil: evidence of a cap carbonate deposited on the Januária basement high

open access: yesBrazilian Journal of Geology
: Sedimentary rocks of the Sete Lagoas Formation, exposed in the left margin of the São Francisco river (Minas Gerais State, Brazil), were deposited on the Januária-Itacarambi basement high.
Pascoal Perrella Júnior   +5 more
doaj   +1 more source

Functional diversity of marine ecosystems after the Late Permian mass extinction event [PDF]

open access: yes, 2014
Article can be accessed from http://www.nature.com/ngeo/journal/v7/n3/full/ngeo2079.htmlThe Late Permian mass extinction event was the most severe such crisis of the past 500 million years and occurred during an episode of global warming.
A Baud   +49 more
core   +1 more source

Disentangling Impact Ejecta Dynamics Using Micro–X‐Ray Fluorescence (μ‐XRF): A Case Study From the Terrestrial Cretaceous‐Paleogene (K‐Pg) Boundary

open access: yesGeochemistry, Geophysics, Geosystems, Volume 26, Issue 8, August 2025.
Abstract This study presents a non‐destructive geochemical and petrographic workflow to generate high‐resolution chemostratigraphic records across key stratigraphic intervals, exemplified by a terrestrial Cretaceous‐Paleogene (K‐Pg) boundary sequence preserved at Starkville South (Raton Basin, Colorado, USA).
Pim Kaskes   +6 more
wiley   +1 more source

Chemostratigraphic Approach to the Study of Resources’ Deposit in the Upper Silesian Coal Basin (Poland)

open access: yesEnergies
The Upper Silesian Coal Basin (USCB), located in southern Poland, is the major coal basin in Poland, and all technological types of hard coal, including coking coal, are exploited. It is also an area of high potential for coal-bed methane (CBM).
Ewa Krzeszowska
doaj   +1 more source

a new Pc-C boundary section [PDF]

open access: yes, 2016
The widespread, terminal Ediacaran Dengying Formation (~ 551–~ 542 Ma) of South China hosts one of the most prominent negative carbonate carbon isotope excursions in Earth's history and thus bears on the correlation of the Precambrian–Cambrian boundary ...
Gamper, A.   +4 more
core   +1 more source

AstroGeoFit. A Genetic Algorithm and Bayesian Approach for the Astronomical Calibration of the Geological Timescale

open access: yesPaleoceanography and Paleoclimatology, Volume 40, Issue 8, August 2025.
Abstract Variations in Earth's orbit and axial tilt induce climatic changes which are recorded in sedimentary deposits. The frequencies of these cyclical variations are integer combinations of the main secular frequencies of the solar system. Analyzing these cycles in sedimentary records can help establish an astronomical time scale for the geological ...
N. Hoang   +7 more
wiley   +1 more source

Quantitative and Nuanced Approaches Elucidate Carbon Isotope Records

open access: yesGeochemistry, Geophysics, Geosystems
Earth scientists have leveraged carbon isotope records to interpret Earth history and establish chronostratigraphic frameworks for decades (e.g., Halverson et al., 2005, https://doi.org/10.1130/b25630.1; Kaufman & Knoll, 1995, https://doi.org/10.1016 ...
Cedric J. Hagen
doaj   +1 more source

Evolution of the South Pacific's Iron Cycle Over the Cenozoic

open access: yesPaleoceanography and Paleoclimatology, Volume 40, Issue 7, July 2025.
Abstract Iron (Fe) availability impacts marine primary productivity, potentially influencing the efficiency of the biological carbon pump. Stable Fe isotope analysis has emerged as a tool to understand how Fe is sourced and cycled in the water column; however its application to sediment records is complicated by overlapping isotope signatures of ...
Logan A. Tegler   +8 more
wiley   +1 more source

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