Article
Geochemistry & Geophysics
Bin Wang, Wei Tian, Bin Fu, Jia-Qi Fang
Summary: The rocks in the Wutai Complex of the North China Craton record extensive fluid activities, indicating the presence of channelized CO2-rich hydrothermal fluids transporting upwards and forming dolomite or quartz precipitation. The results suggest that these fluids may have originated from regional changes in geothermal gradient, experiencing active metasomatism in a Paleoproterozoic subduction zone.
Review
Geosciences, Multidisciplinary
R. Lahtinen, J. Koykka, J. Salminen, M. Sayab, S. T. Johnston
Summary: This study establishes a tectonic model of the Paleoproterozoic Baltica, analyzes the evolution of the region based on stratigraphic correlations and deformation events, and identifies significant tectonic processes involved in its formation.
EARTH-SCIENCE REVIEWS
(2023)
Article
Geochemistry & Geophysics
Lyle L. Nelson, Anne-Sofie C. Ahm, Francis A. Macdonald, John A. Higgins, Emily F. Smith
Summary: The lateral offsets in carbonate-carbon isotope values within the Cryogenian sediment in California are linked to dolomitization, resulting in different values for limestones and dolostones. These variations are attributed to sediment-buffered diagenesis and suggest a local rather than global representation of Cryogenian seawater isotopic values.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
Article
Geography, Physical
Dongping Hu, Xiaolin Zhang, Menghan Li, Yilun Xu, Yanan Shen
Summary: High-resolution carbonate carbon isotope data from the Yangtze Platform in South China reveal five distinct characteristics of δ13C(carb) variations, which can be correlated with equivalent successions in other regions, demonstrating their potential for global correlations. The data also suggest a temporal coincidence between long-term rises in δ13C(carb) and the Great Ordovician Biodiversification Event, indicating a possible role of enhanced organic matter burial in promoting biodiversity during the Ordovician.
GLOBAL AND PLANETARY CHANGE
(2021)
Article
Geochemistry & Geophysics
Hairuo Qing, Zhanfeng Qiao, Siyang Zhang, Jason Cosford, Anping Hu, Feng Liang, Yongsheng Wang, Jianfeng Zheng
Summary: Widespread replacement dolomite in the geologic record is characterized by different crystal sizes and shapes, which can be interpreted as either multistage dolomitization or recrystallization of precursor dolomite. This study used isotopes to investigate the crystal morphologies of Ordovician dolomites from the Tarim Basin, China. The results suggest that the dolomites were formed by the same dolomitizing fluid, and the variation in delta 18O values reflects the degree of recrystallization.
Article
Geosciences, Multidisciplinary
Fred T. Bowyer, Andrey Yu Zhuravlev, Rachel Wood, Graham A. Shields, Ying Zhou, Andrew Curtis, Simon W. Poulton, Daniel J. Condon, Chuan Yang, Maoyan Zhu
Summary: This study presents a new delta C-13(carb) composite reference curve for the Ediacaran Nama Group and proposes four possible global age models for the Ediacaran-Cambrian transition. These models reveal the variability in the terminal Ediacaran and support the pre-BACE first appearance of Cambrian-type shelly fossils in Siberia and possibly South China.
EARTH-SCIENCE REVIEWS
(2022)
Article
Geography, Physical
Sarah J. Beith, Calum P. Fox, John E. A. Marshall, Jessica H. Whiteside
Summary: Compound-specific carbon isotopic analysis of biomarkers and palynological studies provide constraints on the origin of the bulk organic carbon 'initial' isotope excursion during the end-Triassic mass extinction. The analysis reveals that the signal is not derived from large perturbations in the global carbon cycle but from localized source changes. The findings suggest the need for a re-evaluation of temporal relationships between positive climate feedbacks and their effects to more accurately understand mass extinction events.
GLOBAL AND PLANETARY CHANGE
(2023)
Article
Geosciences, Multidisciplinary
Jayagopal Madhavaraju, Robert W. Scott, Kandasamy Selvaraj, Yong Il Lee, Hannes Loser
Summary: The study analyzed nine units of carbonate rocks in Punta China, Baja California, revealing different biological assemblages and stratigraphic features. The presence of high diversity microfossils in Unit 9 indicated a lower Albian age in a shallow marine platform environment. The variations in Sr-86 ratios and carbon isotope curves suggest the occurrence of two oceanic anoxic subevents in the mid-Cretaceous OAE intervals.
GEOLOGICAL JOURNAL
(2021)
Article
Geography, Physical
Antun Husinec, J. Fred Read, Bozo Prtoljan
Summary: This study provides a comprehensive analysis of the delta(13C) fluctuations and sequence stratigraphy of the Middle and Upper Jurassic strata on the Adriatic Platform. It reveals several significant sea-level changes events and suggests that detailed research on similar thick Jurassic isolated platform successions can provide valuable long-term records of delta(13C), climate, and sea-level changes.
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
(2022)
Article
Geochemistry & Geophysics
Kaarel Mand, Noah J. Planavsky, Susannah M. Porter, Leslie J. Robbins, Changle Wang, Timmu Kreitsmann, Kart Paiste, Paarn Paiste, Alexander E. Romashkin, Yulia E. Deines, Kalle Kirsimae, Aivo Lepland, Kurt O. Konhauser
Summary: There is a gap in time between the oxygenation of the atmosphere 2.4 billion years ago and the first widely-accepted fossil evidence for complex eukaryotic cells less than 1.7 billion years ago. The study analyzed chromium-based oxygen proxies in a core from the Onega Basin in Russia and found evidence of higher and more stable oxygen levels in the Paleoproterozoic. This suggests that the delay in the evolution of complex cells was not due to oxygen limitation but could be attributed to other factors or simply the time required for such biological innovations to occur.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geosciences, Multidisciplinary
Guangyou Zhu, Xi Li, Tingting Li, Lei Zhou, Yuxuan Wu, Bing Shen, Meng Ning
Summary: This study clarifies the mechanism of dolomite genesis in the Upper Sinian Qigebulake Formation and the Lower Cambrian Xiaoerbulake Formation in the Tarim Basin. It reveals that dolomite in the Xiaoerbulake Formation primarily originates from Early Cambrian marine fluid, while dolomite in the Qigebulake Formation is influenced by seawater, microorganisms, and sedimentary organic matter. The study also highlights the impact of different sources and fluid properties on the magnesium isotope composition of dolomite during the Sinian-Cambrian transition.
SCIENCE CHINA-EARTH SCIENCES
(2023)
Article
Geochemistry & Geophysics
Wissale Boukirou, Mohammed Bouabdellah, Anton R. Chakhmouradian, Abdellah Mouttaqi, Ekaterina P. Reguir, Folkmar Hauff, Michel Cuney, Michel Jebrak, Johan Yans, Kaj Hoernle
Summary: The Gleibat Lafhouda dolomite carbonatites of the Moroccan Sahara are three separate cone-shaped plugs that intrude an Archean supracrustal basement rocks. These carbonatites have specific geochemical characteristics and may represent the earliest manifestation of the fragmentation of the Columbia supercontinent at 1.85 Ga.
Article
Geochemistry & Geophysics
Sara R. Kimmig, Matthew D. Nadeau, Peter K. Swart, Chris Holmden
Summary: The formation of dolomite may be influenced by subsurface fluid flow, rather than seawater. Analysis of gradients in Sr-87/Sr-86 ratios and δMg-26 values in dolomites can reveal different geological processes affecting dolomitization.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2021)
Article
Geochemistry & Geophysics
Monica Sanchez-Roman, Luis Gibert, Juan Diego Martin-Martin, Kirsten van Zuilen, Victoriano Pineda-Gonzalez, Pieter Vroon, Sylvie Bruggmann
Summary: This study investigates the environmental and biogeochemical conditions under which dolomite precipitated in a sabkha/salina environment. The results reveal that the dolomite formation is influenced by microbial activity in saline environments, indicating the geochemistry of the depositional environment.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Geology
Sean T. Murray, John A. Higgins, Chris Holmden, Chaojin Lu, Peter K. Swart
Summary: This study analyzed the Neogene dolomites in the Bahamas using chemical and isotope analysis, revealing different dolomitization mechanisms and highlighting the utility of multiple geochemical proxies in deciphering the diagenetic history of shallow-water carbonate sediments. The findings caution against simple interpretations of stratigraphic variability in these geochemical proxies.
Article
Geochemistry & Geophysics
Paula Niinikoski, Sami Sarapera, Nina Hendriksson, Juha A. Karhu
APPLIED GEOCHEMISTRY
(2016)
Article
Geochemistry & Geophysics
Elina Sahlstedt, Juha A. Karhu, Petteri Pitkanen, Martin Whitehouse
APPLIED GEOCHEMISTRY
(2016)
Article
Chemistry, Inorganic & Nuclear
Paula I. A. Niinikoski, Nina M. Hendriksson, Juha A. Karhu
ISOTOPES IN ENVIRONMENTAL AND HEALTH STUDIES
(2016)
Article
Geosciences, Multidisciplinary
Andrey Bekker, Bryan Krapez, Stefan G. Muller, Juha A. Karhu
JOURNAL OF THE GEOLOGICAL SOCIETY
(2016)
Article
Water Resources
Paula I. A. Niinikoski, Juha A. Karhu
HYDROLOGY RESEARCH
(2017)
Article
Water Resources
Paula I. A. Niinikoski, Juha A. Karhu
HYDROLOGY RESEARCH
(2017)
Article
Geology
Joakim Donner, Eloni Sonninen, Juha Karhu, Aarno Kotilainen
BULLETIN OF THE GEOLOGICAL SOCIETY OF FINLAND
(2014)
Article
Geosciences, Multidisciplinary
P. E. Salminen, A. T. Brasier, J. A. Karhu, V. A. Melezhik
PRECAMBRIAN RESEARCH
(2014)
Article
Geochemistry & Geophysics
Matthew S. Dodd, Dominic Papineau, Zhen-Bing She, Chakravadhanula Manikyamba, Yu-Sheng Wan, Jonathan O'Neil, Juha A. Karhu, Hanika Rizo, Franco Pirajno
EARTH AND PLANETARY SCIENCE LETTERS
(2019)
Article
Geography, Physical
Laura Arppe, Juha A. Karhu, Sergey Vartanyan, Dorothee G. Drucker, Heli Etu-Sihvola, Herve Bocherens
QUATERNARY SCIENCE REVIEWS
(2019)
Article
Multidisciplinary Sciences
Matthew S. Dodd, Dominic Papineau, Franco Pirajno, Yusheng Wan, Juha A. Karhu
NATURE COMMUNICATIONS
(2019)
Review
Geosciences, Multidisciplinary
Andrey Bekker, Bryan Krapez, Juha A. Karhu
EARTH-SCIENCE REVIEWS
(2020)
Editorial Material
Geosciences, Multidisciplinary
Andrey Bekker, Bryan Krapez, Juha A. Karhu, Kevin Chamberlain
Summary: Bekker et al. (2020) and Philippot et al. (2018) discussed the geological and geochemical records of the Turee Creek Basin in Western Australia in relation to the Great Oxidation Episode (GOE). They disagreed on the interpretation of the geochronological data and tectonostratigraphic evolution, impacting theories on the GOE and early Paleoproterozoic climate changes. The study provided a nuanced view on global correlations and events during the early Paleoproterozoic era.
EARTH-SCIENCE REVIEWS
(2021)
Editorial Material
Geology
A. Bekker, A. El Albani, A. Hofmann, J. A. Karhu, L. Kump, F. Ossa Ossa, N. Planavsky
Article
Geochemistry & Geophysics
Minja Seitsamo-Ryynanen, Juha A. Karhu, Petteri Pitkanen, Martin Whitehouse
Summary: The geochemical characteristics of precipitated fracture filling calcite and pyrite can provide valuable information about the deep bedrock environment. However, it is challenging to identify fracture coatings deposited from the present-day groundwater system. This study investigated the relationship between coexisting calcite and pyrite and the groundwater at the time of precipitation, using mineral precipitates collected from a drillhole at Olkiluoto. The findings suggest that the calcite is in near isotopic equilibrium with the surrounding environment, while the pyrite shows a restricted range of isotopic values due to open system conditions during precipitation.
APPLIED GEOCHEMISTRY
(2022)