Article
Geochemistry & Geophysics
Maochao Zhang, Zheng Gong, Jun Li, Yuanyuan Pan, Qian Jin, Chengmin Huang
Summary: Paleo-weathering crust rare earth element (REE) sedimentary ores (PWREOs), related to weathering of the Permian Emeishan basalts, were studied in Guizhou Province, China. The paleosols showed enrichment of light REEs relative to heavy REEs, with high concentrations of REEs found in kaolinite-rich horizons. The weathering products, including claystones, also showed enrichment of REEs. The formation of PWREOs involves the initial high REE contents in the Emeishan basalts, the primary enrichment during weathering, and the further enrichment during transportation and sedimentation.
JOURNAL OF GEOCHEMICAL EXPLORATION
(2023)
Article
Geosciences, Multidisciplinary
C. A. Sidor, J. A. Mcintosh, B. M. Gee, W. R. Hammer, P. J. Makovicky, N. D. Smith, R. M. H. Smith, N. J. Tabor, M. R. Whitney, C. H. Woolley
Summary: The Permian-Triassic rocks in the Transantarctic Basin offer a valuable record of high latitude paleoenvironments and terrestrial vertebrate faunas. This study summarizes the taxonomic and paleoecological implications of collected vertebrate fossils and presents new geological observations. The results reveal the similarities and differences between the Fremouw Formation and the Karoo Basin, as well as provide insights into the depositional environments and diagenetic alterations of these formations.
EARTH-SCIENCE REVIEWS
(2023)
Article
Geography, Physical
Gregory J. Retallack, Adrian P. Broz, Larry S-H Lai, Kevin Gardner
Summary: The study reveals the presence of different types of paleosols in the Chuar Group in the eastern Grand Canyon, with new chemical and petrographic data shedding light on the evolutionary history of microbial soil communities during the geological period.
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
(2021)
Article
Geosciences, Multidisciplinary
Pedro Martinez, Alessandro Batezelli, Francisco Ladeira, Leticia Correa, Diego Luciano Nascimento
Summary: This study investigates the paleoenvironmental significance of kaolinite-rich weathering fronts in the Cretaceous Sanfranciscana Basin in Brazil. The results suggest that the basin experienced climatic amelioration and a rise in water table level during the Cretaceous, leading to dune stabilization and the formation of an extensive geomorphic surface.
Article
Plant Sciences
Christopher Harris, Robert W. Gess, Cyrille Prestianni, Marion K. Bamford
Summary: New fossil material of Famennian plants from South Africa extends the temporal range of Colpodexylon, formerly only known from lower Frasnian and older strata, indicating the genus persisted at high latitudes.
REVIEW OF PALAEOBOTANY AND PALYNOLOGY
(2021)
Article
Geosciences, Multidisciplinary
Lixin Gu, Yongjin Chen, Yuchen Xu, Xu Tang, Yangting Lin, Takaaki Noguchi, Jinhua Li
Summary: This study reports the characteristics of space weathering on lunar soils collected by Chang'e-5, showing that micrometeorite impacts and solar wind irradiation have significantly modified the composition and microstructure of the lunar soil materials. The exposed mineral phases on the surface of a basalt clast have a vapor deposit layer, and the textures of the solar wind irradiation-damaged zone vary depending on the host mineral species. The findings contribute to the understanding of the reflectance spectra of the Moon.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Environmental Sciences
Giulia Lovati, Paola De Michelis, Giuseppe Consolini, Francesco Berrilli
Summary: The pressure-gradient current is a weaker ionospheric current system caused by plasma pressure variations. It produces a magnetic field opposite to the ambient magnetic field and forms well-defined flow patterns in the high-latitude ionosphere. These currents, although small in amplitude, are ubiquitously present and can cause artifacts in the main field models.
Article
Geochemistry & Geophysics
Kai -Chen Xing, Feng Wang, Fang-Zhen Teng, Wen-Liang Xu, Ming Li, Yue-Wu Sun, De-Bin Yang
Summary: The Triassic-Jurassic boundary is a crucial period for studying chemical weathering intensity and climatic change. In this study, Mg-Zn-Cu isotopic data from a terrestrial sedimentary section in the southern margin of the Junggar Basin in high latitude Asia are analyzed, revealing a reduced sedimentary environment and increasingly intensive chemical weathering across the boundary, responding to a warmer and more humid paleoclimate. This regional climatic change in high latitude areas can be linked to known global climate change during this period, providing new insights into the global pattern of climate change at the Triassic-Jurassic boundary.
Article
Environmental Sciences
Leonie Bernet, Tove Svendby, Georg Hansen, Yvan Orsolini, Arne Dahlback, Florence Goutail, Andrea Pazmino, Boyan Petkov, Arve Kylling
Summary: After the decrease of ODSs, it is still challenging to detect a recovery in total ozone at northern high latitudes. This study investigates total ozone changes at three stations in Norway during the 2000-2020 ozone-recovery period. Measurements from various instruments were combined and trends were derived using the LOTUS project's regression model. The results contribute to a better understanding of regional total ozone trends and the response of Arctic ozone to changes in ODSs and climate change.
ATMOSPHERIC CHEMISTRY AND PHYSICS
(2023)
Article
Geochemistry & Geophysics
Jon K. Golla, Julien Bouchez, Marie L. Kuessner, Daniella M. Rempe, Jennifer L. Druhan
Summary: This study investigates the long-term relationships between stream chemistry and discharge, and how they are regulated by watershed subsurface structure and biogeochemical functioning. The findings reveal that during intense storm events, stream lithium isotope signatures can record the routing of water and generation of solutes within the hillslope, providing insights into the variability of stream chemistry. These results have significant implications for understanding stream ecosystems and hydrogeochemical processes.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Multidisciplinary Sciences
Robert Gess, Per Ahlberg
Summary: We describe a new species of giant bony fish, H. udlezinye sp. nov., from the Late Devonian fossil assemblage in South Africa. This species, belonging to the extinct clade Tristichopteridae, closely resembles H. lindae from Pennsylvania, USA. The discovery of H. udlezinye suggests that Hyneria is not limited to the Euramerican region but also existed in Gondwana, supporting the idea that giant tristichopterids originated in Gondwana.
Article
Geochemistry & Geophysics
Mao-Yong He, Ji-Bao Dong, Zhangdong Jin, Chun-Yao Liu, Jun Xiao, Fei Zhang, He Sun, Zhi-Qi Zhao, Long-Fei Gou, Wei-Guo Liu, Chong-Guang Luo, You-Gui Song, Long Ma, Li Deng
Summary: The study investigated the Li contents and delta Li-7 values in loess deposits to understand pedogenic processes, showing that variations in [Li](leachate) and delta Li-7(leachate) can trace soil water migration processes and the magnitude of pedogenic processes in loess-paleosol sediment at different periods.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2021)
Article
Geosciences, Multidisciplinary
Peixin Zhang, Minfang Yang, Jing Lu, Longyi Shao, Ziwei Wang, Jason Hilton
Summary: The Late Paleozoic Ice Age was a significant glacial event in Earth's history, and this study focuses on reconstructing the chronostratigraphy and climate change during this period in the North China Plate. The research reveals a cool-humid and warm-humid climate mode during glacial and nonglacial periods, respectively, in the low-latitude NCP.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Geography, Physical
Jiquan Chen, Yuan Gao, Daniel E. Ibarra, Jianming Qin, Chengshan Wang
Summary: This study quantitatively reconstructs mean annual precipitation in East Asia during the late Cretaceous to the early Paleogene period using paleosol sequences and proxies. The results show that changes in precipitation are associated with climate warming and cooling events, and also coincide with climate fluctuations and geological events. The study also suggests that ongoing anthropogenic CO2 emissions may lead to increased precipitation in East Asia.
GLOBAL AND PLANETARY CHANGE
(2022)
Article
Geochemistry & Geophysics
Hongjin Chen, Germain Bayon, Zhaokai Xu, Tiegang Li
Summary: The Oceanic Anoxic Event 2 (OAE 2) during the late Cretaceous was characterized by extreme carbon cycle perturbations and major environmental and climate reorganization in terrestrial and marine realms. Chemical weathering of continental rocks played a crucial role in OAE 2, promoting marine primary production and organic carbon burial, and potentially driving the termination of OAE 2 through atmospheric CO2 drawdown. This study focuses on the evolution of continental chemical weathering in high-latitude regions during OAE 2.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Pharmacology & Pharmacy
Laura Viidik, Jemina Vesala, Riikka Laitinen, Ossi Korhonen, Jarkko Ketolainen, Jaan Aruva, Kalle Kirsimae, Karin Kogermann, Jyrki Heinamaki, Ivo Laidmae, Tuomas Ervasti
Summary: Hot-melt extruded (HME) filaments are essential for 3D printing drug delivery systems (DDS) using fused deposition modelling (FDM). This study designed novel polymeric HME filaments loaded with active pharmaceutical ingredients (APIs), and investigated their physical properties, mechanical properties, drug release, and short-term stability. The combination of polycaprolactone (PCL) and arabic gum (ARA) showed promise as a carrier system for 3D-printable HME filaments and tablets, with sustained drug release observed in vitro.
EUROPEAN JOURNAL OF PHARMACEUTICAL SCIENCES
(2021)
Article
Geochemistry & Geophysics
Clara L. Blattler, Wei-Li Hong, Kalle Kirsimae, John A. Higgins, Aivo Lepland
Summary: The study investigated the precipitation of authigenic carbonate minerals in a methane seep system in the northern Barents Sea, providing new constraints on the relationship between precipitation rate and calcium isotope fractionation. This research contributes valuable information for advancing the mechanistic understanding of calcium isotope fractionation and trace element distributions in carbonate minerals in geological applications.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2021)
Article
Geosciences, Multidisciplinary
A. R. Prave, K. Kirsimae, A. Lepland, A. E. Fallick, T. Kreitsmann, Yu E. Deines, A. E. Romashkin, D. Rychanchik, P. Medvedev, M. Moussavou, K. Bakakas, M. S. W. Hodgskiss
Summary: The study suggests that the C-13 isotope trend of the LJE is facies-dependent rather than representative of the global carbon cycle. While open and deeper marine environments maintained stable carbon isotope values, nearshore and evaporitic environments showed higher C-13 values. Changes in C-13 values are linked to facies changes and may be related to local carbon pools.
JOURNAL OF THE GEOLOGICAL SOCIETY
(2022)
Article
Geochemistry & Geophysics
Wei-Li Hong, Aivo Lepland, Kalle Kirsimaee, Antoine Cremiere, James W. B. Rae
Summary: The boron content and isotopic composition of marine carbonates can provide information on CO2 chemistry during carbonate growth conditions. However, there are challenges in obtaining and interpreting boron compositions from authigenic carbonates. This study presents data and modeling results on methane-derived authigenic carbonate (MDAC) from three sites along the Norwegian margin. A novel sequential leaching method is used to isolate boron signals from different carbonates in these complex samples, and a numerical model is constructed to simulate the evolution of boron isotopic composition. The results show that various factors contribute to the observed boron compositions in the carbonates. However, the multiple controls on boron in these diagenetic settings limit the ability to uniquely determine fluid CO2 chemistry using boron in authigenic carbonates.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Paleontology
Oive Tinn, Liisa Lang, Tiiu Marss, Signe Vahur, Kalle Kirsimae
Summary: The study on the dorsal head shield of the ancient fish Kalanaspis delectabilis revealed a unique carbonaceous mode of preservation, previously undocumented among vertebrate fossils. This unusual preservation pattern is key to understanding the fossilization history and taphonomic conditions of the whole Kalana Lagerstatte, indicating potential microbial involvement.
Article
Geochemistry & Geophysics
Weiduo Hao, Ning Chen, Wenyuan Sun, Kaarel Mand, Kalle Kirsimae, Yoram Teitler, Peeter Somelar, Leslie J. Robbins, Michael G. Babechuk, Noah J. Planavsky, Daniel S. Alessi, Kurt O. Konhauser
Summary: This study investigates the binding mechanisms of Cr(III) on clay minerals and finds that Cr(III) precipitates on clay surfaces as guyanaite. The adsorption capacity of Cr(III) is highest on kaolinite. The results suggest that under intense chemical weathering conditions, kaolinite can immobilize Cr(III) and facilitate its transport to coastal environments.
EARTH AND PLANETARY SCIENCE LETTERS
(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
Geochemistry & Geophysics
K. Paiste, D. A. Fike, K. Kirsimae, C. Jones, A. Lepland
Summary: The Paleoproterozoic metasedimentary rocks of the Zaonega Formation in NW Russia provide important information about global environmental changes after the initial oxygenation of the Earth's atmosphere and oceans. This study examines the geochemical signals preserved in these rocks and their environmental meaning, particularly focusing on the unusually high pyrite sulfur isotope ratios. The results show that the formation of pyrite in the Zaonega Formation occurred through multiple stages, and early-stage pyrite has different isotopic signatures compared to late-stage pyrite. The findings suggest that a thorough understanding of the geological context and mechanisms associated with sulfur cycling and pyrite formation is essential for interpreting the isotopic records accurately.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2022)
Article
Geosciences, Multidisciplinary
Sigrid Soomer, Peeter Somelar, Kaarel Mand, Aivo Lepland, Kalle Kirsimae
Summary: This passage examines the intensification of chemical weathering on Earth's surface and the impact of the Great Oxygenation Event on silicate weathering. The study suggests that the event did not significantly alter weathering intensity, which was largely influenced by pre-existing factors.
PRECAMBRIAN RESEARCH
(2022)
Article
Engineering, Chemical
T. Thomberg, P. Ramah, A. Lust, J. Nerut, M. Koppel, T. Romann, R. Palm, M. Mansson, N. M. Flores March, H. Junninen, M. Kulaviir, P. Paiste, K. Kirsimae, M. Punapart, L. Viru, A. Merits, E. Lust
Summary: Nanowire PVDF polymer membranes activated with Ag and Zn nanoclusters were prepared using the electrospinning method. The structure of membranes was varied by adjusting polymer concentrations, electric field strength, and nanocluster concentrations. The concentration of Ag and Zn nanoclusters in the membranes affected the activity of the nanofibers. The nanofibers activated with Zn nanoclusters showed significantly higher and concentration-independent virucidal activity compared to those activated with Ag nanoclusters.
SEPARATION AND PURIFICATION TECHNOLOGY
(2022)
Article
Environmental Sciences
Mohit Masta, Mikk Espenberg, Sharvari S. Gadegaonkar, Jaan Parn, Holar Sepp, Kalle Kirsimae, Fotis Sgouridis, Christoph Mueller, Ulo Mander
Summary: Peatlands play a significant role in nitrous oxide (N2O) emissions, with bacterial denitrification being the primary source and nitrification as a secondary source. The study found that under intermediate and flooded conditions, ammonia oxidation was also a source of N2O, and dissimilatory nitrate reduction to ammonium (DNRA) potentially contributed to N2O emissions. The combination of isotopic and microbial analyses provided insights into the processes involved in N2O emissions.
Article
Geochemistry & Geophysics
Qin Huang, Dao-Hui Pi, Shao-Yong Jiang, Deng Liu, Hao Yan, Kaarel Mand, Kalle Kirsimae, Brendan Bishop, Leslie J. Robbins, Shan-Shan Yang
Summary: Microbial activity plays a significant role in the formation of manganese carbonate deposits, acting as a crucial factor in enhancing the saturation state of Mn carbonates in pore waters. The nucleation of Mn carbonates on cellular templates and the microbial reduction of Mn(IV) oxides contribute to the formation of Mn-carbonate ores with unique core-shell structures and specific morphologies.
Article
Geology
Malcolm S. W. Hodgskiss, Nivedita Thiagarajan, Yue Wang, Niels Rameil, Harald Brunstad, Erik Hammer, Jon Halvard Pedersen, Kalle Kirsimae, Atle Mork, Aivo Lepland
Summary: A Carboniferous to early Permian carbonate and evaporite succession from the Finnmark Platform in the southern Barents Sea contains nodules of anhydrite replaced by calcite spar and native sulfur, which are genetically connected to hydrocarbon migration and/or oxidation. In situ U-Pb dating of calcite spar can provide insights into the timing of hydrocarbon migration and the geochemical and temperature conditions during this event.
Article
Thermodynamics
Birgit Maaten, Andres Siirde, Signe Vahur, Kalle Kirsimae
Summary: This study focused on the fast pyrolysis process and properties of the produced materials during Estonian oil shale pyrolysis. Different properties of shale oil can be obtained depending on the process conditions. Understanding the process and properties can contribute to the development of oil shale utilization.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2023)
Article
Astronomy & Astrophysics
Eva E. Stueken, Kalle Kirsimae, Aivo Lepland, Anthony R. Prave
Summary: Hydrothermal vents are important in the search for life on other planets due to their ability to generate catalytic surfaces and organic compounds. This study investigates the role of hydrothermal circulation in maintaining a biosphere beyond its origin by analyzing organic carbon, nitrogen abundances, and isotopic ratios from ancient rocks in Russia. The results suggest that hydrothermal activity in ancient marine basins could provide a high flux of recycled nitrogen, supporting a large biosphere on anoxic worlds.
