Results 31 to 40 of about 3,960 (136)

In Situ Rb/Sr Geochronology and Stable Isotope Geochemistry Evidence for Neoproterozoic and Paleozoic Fracture‐Hosted Fluid Flow and Microbial Activity in Paleoproterozoic Basement, SW Sweden

Geochemistry, Geophysics, Geosystems, Volume 24, Issue 5, May 2023., 2023
Abstract Recent studies have shown that biosignatures of ancient microbial life exist in mineral coatings in deep bedrock fractures of Precambrian cratons, but such surveys have been few and far between. Here, we report results from southwestern Sweden in an area of 1.6–1.5 Ga Paleoproterozoic rocks heavily reworked by the 1.14–0.96 Ga Sveconorwegian ...
Henrik Drake, Mikael Tillberg, Manuel Reinhardt, Martin J. Whitehouse, Ellen Kooijman   +4 more
wiley   +1 more source

Petrographic studies and mineralogical characterization of the Dellen impactites

Meteoritics &Planetary Science, Volume 58, Issue 4, Page 480-500, April 2023., 2023
Abstract The impact origin of the Early Cretaceous (140.82 ± 0.51 Ma) 20‐km diameter Dellen structure was proven in the late 60s based on the discovery of planar deformation features (PDFs) in quartz grains. Although decades have passed, impactites found from the crater have not received much attention. Thus, this study provides a detailed petrological
Satu Hietala, Herbert Henkel, Jüri Plado   +2 more
wiley   +1 more source

Heterogeneity Versus Anisotropy and the State of Stress in Stable Cratons: Observations From a Deep Borehole in Northeastern Alberta, Canada

Journal of Geophysical Research: Solid Earth, Volume 128, Issue 3, March 2023., 2023
Abstract Geophysical logs collected from a deep borehole drilled into the North American Craton in Northeastern Alberta shed valuable light on the state of stress in stable cratons. Observed breakout (BO) azimuths rotate between three depth intervals, ranging from 100° at 1,650–2,000 m to 173° at 2,000–2,210 m, and finally to 145° at the bottom.
Wenjing Wang, Douglas R. Schmitt, Judith Chan   +2 more
wiley   +1 more source

Keurusselkä impact structure, Finland—Overview, new observations, and renewed interpretation of the size

Meteoritics &Planetary Science, Volume 57, Issue 11, Page 2063-2080, November 2022., 2022
Abstract The Keurusselkä structure is one of Finland's 12 meteorite impact structures—one of the world's oldest (1150 ± 10 Ma) and the largest of its kind in Finland. Findings of numerous well‐formed shatter cones in a wide area have helped define and prove Keurusselkä's impact origin.
Satu Hietala, Jarmo Moilanen, Jüri Plado   +2 more
wiley   +1 more source

The Oripää granite, SW Finland: characterization and significance in terms of Svecofennian crustal evolution [PDF]

, 2001
Granitoid rocks of the Finnish Svecofennian have recently been at the focus of active research and new ideas regarding their petrogenesis and tecton-ic evolution have been presented by several ...
Mikko Nironen, Tapani Rämö
core   +1 more source

Petrophysics of Chicxulub Impact Crater's Peak Ring

Journal of Geophysical Research: Solid Earth, Volume 127, Issue 5, May 2022., 2022
Abstract A new set of physical property measurements was undertaken on 29 peak‐ring samples from the IODP‐ICDP Expedition 364. Among the studied lithologies, the dominant one recovered in the peak ring consists of shocked granitoid rocks (19 samples).
E. Le Ber, D. Loggia, N. Denchik, J. Lofi, D. A. Kring, P. Sardini, M. Siitari‐Kauppi, P. Pezard, G. Olivier, IODP‐ICDP Expedition 364 Science Party   +9 more
wiley   +1 more source

New monazite U-Pb age constraints on the evolution of the Paleoproterozoic Vaasa granitoid batholith, western Finland [PDF]

, 2016
The Vaasa batholith, western Finland, is a large, peraluminous granitoid pluton that crystallized at 1.88-1.87 Ga during the culmination of the Svecofennian orogeny.
Hölttä, Pentti, Kotilainen, Anna K., Kurhila, Matti, Mänttäri, Irmeli, Rämö, O. Tapani   +4 more
core   +2 more sources

Sediment sequence at Muhos, western Finland – a window to the Pleistocene history of the Scandinavian Ice Sheet

Boreas, Volume 51, Issue 2, Page 332-349, April 2022., 2022
In this study, we analysed a ~54‐m sediment core consisting of Quaternary sediments overlying the Neoproterozoic Muhos Formation in central western Finland, adjacent to the Gulf of Bothnia. The sediments recovered were logged, and their sedimentological characteristics defined.
Tiina Eskola, Juha P. Lunkka
wiley   +1 more source

1.88 Ga granitoids at Sorsakoski, Central Finland: A-type magmatism within the Raahe-Ladoga suture zone [PDF]

Bulletin of the Geological Society of Finland
Four quartz monzonite – granite intrusions forming the Sorsakoski granite lithodeme, are found within the Raahe-Ladoga suture zone in Central Finland. The prevailing potassium feldspar megacrystic quartz monzonites and granites form a bimodal association
Perttu Mikkola, Maija Pietilä, O. Tapani Rämö, Hannu Huhma   +3 more
doaj   +1 more source

The Vaasa Migmatitic Complex (Svecofennian Orogen, Finland): Buildup of a LP‐HT Dome During Nuna Assembly

Tectonics, 2020
Tectonic evolution of the Paleoproterozoic Vaasa migmatitic complex (VMC) in the central part of the Svecofennian accretionary orogen is deciphered using aeromagnetic and gravity maps, deep seismic and magnetotelluric profiles, and structural and ...
F. Chopin, A. Korja, K. Nikkilä, P. Hölttä, T. Korja, M. Abdel Zaher, M. Kurhila, O. Eklund, O. T. Rämö   +8 more
semanticscholar   +1 more source