Article
Geography, Physical
Olle Hints, Leho Ainsaar, Aivo Lepland, Merlin Liiv, Peep Mannik, Tonu Meidla, Jaak Nolvak, Sigitas Radzevicius
Summary: This study establishes a biostratigraphic and chemostratigraphic reference section for the late Katian to Rhuddanian stages in the Baltic region based on the Likenai 396 drill core in northern Lithuania. The main focus is on the Hirnantian carbon isotopic event (HICE) interval and the late Katian Paroveja excursion. The Likenai core is a suitable reference section for the Paroveja excursion and the falling limb of the HICE in the Baltoscandia region.
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
(2023)
Article
Geosciences, Multidisciplinary
Jixin Jia, Xuebin Du, Ke Zhao, Yongchao Lu, Chao Tan
Summary: During the Ordovician-Silurian transition, large-scale explosive volcanism occurred globally, including in South China. The tectonic activities leading to this volcanism in the South China Block, particularly on the northern and southern margins, are still debated. Through the analysis of the sources of K-bentonite layers in South China during this transition, it is revealed that there were two different sources of volcanic activity, suggesting different geodynamic settings, including within-plate extension and subduction-collision processes.
MARINE AND PETROLEUM GEOLOGY
(2022)
Article
Geosciences, Multidisciplinary
Xuebin Du, Jixin Jia, Ke Zhao, Jiacheng Shi, Yi Shu, Zhanhong Liu, Dan Duan
Summary: The volcanic activity in South China during the Ordovician-Silurian transition was not only part of global volcanic activity but also had unique characteristics, being potentially stronger and occurring slightly later than in other areas. The distribution of volcanic ash beds in South China corresponds to specific stages, indicating a potential influence on the formation of organic-rich shale.
MARINE AND PETROLEUM GEOLOGY
(2021)
Article
Geosciences, Multidisciplinary
Ke Zhao, Xuebin Du, Yongchao Lu, Fang Hao, Zhanhong Liu, Jixin Jia
Summary: Subaerial volcanism and atmospheric volcanic ash deposition can greatly affect the nutrient content and redox conditions of the surface ocean. Study of volcanic ash and shale samples from the Ordovician-Silurian transition reveals anoxic and high-productivity environments, with leaching removing significant amounts of Fe, Si, and P from the volcanic ash, potentially enhancing marine primary productivity. The preservation of organic matter was influenced by redox conditions, with volcanic ash serving as a dominant nutrient source for primary productivity.
GEOLOGICAL SOCIETY OF AMERICA BULLETIN
(2021)
Article
Geosciences, Multidisciplinary
Jeffrey S. Hannon, Craig Dietsch, Warren D. Huff
Summary: This study analyzed the geochemistry and isotopic compositions of bentonite beds from Cretaceous strata in Wyoming and South Dakota. The results showed variations in magmatic processes and the effects of mineral fractionation over a 40 million year period, providing insights into the evolution of volcanic arcs and plutonic rocks in the region.
GEOLOGICAL SOCIETY OF AMERICA BULLETIN
(2021)
Article
Geochemistry & Geophysics
Tarmo Kiipli
Summary: The present study explores the possibility of applying zircon saturation thermometry to heavily altered volcanic ashes-bentonites. A new method using the Zr (ppm)/Al2O3 (%) ratio and compositional corrections from the TiO2/Al2O3 ratio was proposed to estimate source magma temperatures in strongly altered volcanic ashes. The accuracy of the new method was established through comparison with a previous method, with differences mostly within +/- 30 to +/- 50 degrees. This new method allows for differentiation between felsic source magmas originating at low or high temperatures.
Review
Geosciences, Multidisciplinary
Simon A. Larsson, Malin E. Kylander, A. Britta K. Sannel, Dan Hammarlund
Summary: This study aims to investigate the spatial and temporal behavior of rapid climate shifts during the Last Glacial-Interglacial Transition using tephrochronology. The results suggest that the Younger Dryas stadial may be more synchronous than previously thought, but further research is needed to improve temporal precision.
Article
Geology
Tarmo Kiipli
Summary: The study analyzed sixty-one K-bentonite samples from Ludlow-Pridoli sections in western Ukraine and Moldova to interpret the temperature characteristics of their source magmas, revealing continental crust melting during subduction of a hydrated oceanic plate and volcanic sources possibly located within the developing Scythian Platform on the southeastern margin of the East European Platform. This study demonstrates the potential of using immobile elements for correlating volcanic ash layers between different sections.
GEOLOGICAL QUARTERLY
(2021)
Article
Geosciences, Multidisciplinary
Tarmo Kiipli, Rutt Hints, Toivo Kallaste, Arne T. Nielsen, Siim Pajusaar, Niels H. Schovsbo
GEOLOGICAL JOURNAL
(2020)
Review
Geography, Physical
Enli Kiipli, Tarmo Kiipli
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
(2020)
Article
Paleontology
Misha Whittingham, Sigitas Radzevicius, Andrej Spiridonov
Article
Geosciences, Multidisciplinary
Andrej Spiridonov, Robertas Stankevic, Tomas Gecas, Antanas Brazauskas, Donatas Kaminskas, Petras Musteikis, Tomas Kaveckas, Tonu Meidla, Giedrius Bickauskas, Leho Ainsaar, Sigitas Radzevicius
Article
Geology
Darja Dankina, Andrej Spiridonov, Girts Stinkulis, Esther Manzanares, Sigitas Radzevicius
Summary: The study describes a late Permian ichthyofauna from Latvia, including chondrichthyan teeth and actinopterygian scales. Compared to the contemporaneous Lopingian complex in Lithuania, this assemblage is more diverse and abundant.
JOURNAL OF IBERIAN GEOLOGY
(2021)
Article
Energy & Fuels
Anna Cichon-Pupienis, Ralf Littke, Jurga Lazauskiene, Alireza Baniasad, Donatas Pupienis, Sigitas Radzevicius, Laurynas Siliauskas
Summary: The study of more than 100 m-long core sections from Western Lithuanian Baltic Basin reveals a continuous lower Silurian sedimentary record with rich organic matter content, showing the main forces influencing organic matter enrichment to be climate-triggered sea level changes, tectonically-driven environmental effects, and enhanced paleoproductivity leading to oxygen-restricted conditions. Analyzing geochemical and sedimentological data, the study also highlights the various factors affecting organic matter preservation efficiency throughout the early Silurian period.
INTERNATIONAL JOURNAL OF COAL GEOLOGY
(2021)
Article
Geosciences, Multidisciplinary
Simona Rinkeviciute, Robertas Stankevic, Sigitas Radzevicius, Tonu Meidla, Andrius Garbaras, Andrej Spiridonov
Summary: The Mulde event during the Silurian period was identified through fossil records and stable carbon isotopic data, with ostracods playing a significant role in understanding this global geobiological event. Analysis showed that the Mulde/lundgreni event had a negligible effect on the increasing alpha diversity trend during the Mid- to Upper Wenlock.
JOURNAL OF THE GEOLOGICAL SOCIETY
(2022)
Article
Geosciences, Multidisciplinary
Misha Whittingham, Andrej Spiridonov, Sigitas RadzeviCius
Summary: The research found that the counts of sicular annuli in monograptids fluctuated greatly over the Silurian period, but showed negligible variation between species, indicating that this trait is ecophenotypic. The presence of annuli fluctuated in alignment with variations in sea level fluctuations, delta C-13 ratios, and primary productivity, suggesting that annuli were more plentiful in high-stand states associated with wetter climates and more productive conditions. The hypothesis is that upwelling as a result of intensified storm events during wetter periods would have encouraged phytoplankton blooms, increasing the construction of annuli.
EARTH AND ENVIRONMENTAL SCIENCE TRANSACTIONS OF THE ROYAL SOCIETY OF EDINBURGH
(2022)
Article
Geochemistry & Geophysics
Tarmo Kiipli
Summary: The present study explores the possibility of applying zircon saturation thermometry to heavily altered volcanic ashes-bentonites. A new method using the Zr (ppm)/Al2O3 (%) ratio and compositional corrections from the TiO2/Al2O3 ratio was proposed to estimate source magma temperatures in strongly altered volcanic ashes. The accuracy of the new method was established through comparison with a previous method, with differences mostly within +/- 30 to +/- 50 degrees. This new method allows for differentiation between felsic source magmas originating at low or high temperatures.
Article
Geology
Sigitas Radzevicius, Robertas Stankevic, Rimvydas Budginas, Anna Cichon-Pupienis, Agne Venckute-Aleksiene, Tonu Meidla, Leho Ainsaar, Andrej Spiridonov
Summary: This study investigates the evolution and climate perturbations during the Ludlow Epoch of the Silurian Period using a comprehensive record of graptolites, delta C-13, and delta O-18 of carbonates. The analysis reveals different graptolite biozones and an ascending portion of the mid-Ludfordian excursion in the delta C-13 trend. The study also demonstrates a significant interaction between delta C-13 and delta O-18, with delta O-18 driving the changes in delta C-13. Additionally, a distinct periodicity in delta O-18 with a period length of approximately 1 Myr is interpreted as a climatic signal of long-period amplitude modulation of obliquity.
NEWSLETTERS ON STRATIGRAPHY
(2023)
Article
Geosciences, Multidisciplinary
Milda Grendaite, Dainius Michelevicius, Sigitas Radzevicius
Summary: The geological structure of the sedimentary cover of the Baltic Basin in Western Lithuania has been investigated using newly acquired seismic data. The study reveals detailed depth maps and seismic profiles that illustrate the geological structure of the area, including new features such as erosional remnants and structural features related to the Zechstein Basin.
MARINE AND PETROLEUM GEOLOGY
(2023)
Article
Geology
Sigitas Radzevicius, Robertas Stankevic, Rimvydas Budginas, Anna Cichon-Pupienis, Agne Venckute-Aleksiene, Tonu Meidla, Leho Ainsaar, Andrej Spiridonov
Summary: The Ludlow Epoch of the Silurian Period is crucial for understanding the evolution of marine biota and climate perturbations. This study presents an integrated record of graptolites, delta C-13, and delta O-18 of carbonates from a deep shelf section in the Silurian Baltic Basin. The data reveals distinct graptolite biozones and an ascending portion of the mid-Ludfordian excursion in the delta C-13 trend. The study also explores the interaction between delta C-13 and delta O-18, with the latter driving the former. Spectral and recurrence quantification analyses suggest a climatic signal with a periodicity of approximately 1 Myr.
NEWSLETTERS ON STRATIGRAPHY
(2023)
Article
Paleontology
Darja Dankina, Andrej Spiridonov, Pawel Raczynski, Sigitas Radzevicius
Summary: This study presents new ichthyofaunal material from the Zechstein Basin, revealing the presence of chondrichthyans and osteichthyans for the first time in the Nowy Kosciol quarry in SW Poland. The diverse actino-pterygian tooth shapes suggest significant ecological differentiation of fishes exploring different modes of feeding in the late Permian, even in hyper-saline conditions of an epicontinental sea.
ACTA PALAEONTOLOGICA POLONICA
(2021)
Article
Geology
Tarmo Kiipli
Summary: The study analyzed sixty-one K-bentonite samples from Ludlow-Pridoli sections in western Ukraine and Moldova to interpret the temperature characteristics of their source magmas, revealing continental crust melting during subduction of a hydrated oceanic plate and volcanic sources possibly located within the developing Scythian Platform on the southeastern margin of the East European Platform. This study demonstrates the potential of using immobile elements for correlating volcanic ash layers between different sections.
GEOLOGICAL QUARTERLY
(2021)
