Results 11 to 20 of about 6,981 (220)

Deciphering the geochemistry of two key Paleoproterozoic siliciclastic sequences of the Piedra Alta Terrane (Río de la Plata Craton, Uruguay)

Agrociencia Uruguay, 2022
The geochemistry of two metavolcano-sedimentary sequences deposited in the Piedra Alta Terrane is compared, and their geotectonic evolution is discussed.
Gonzalo Blanco, Paulina Abre, Mabel Lanfranchini, Carlos A. Cingolani, Hector Ferrizo, Daniel Piñeyro, Norberto J. Uriz, Manuela E. Benítez   +7 more
doaj   +1 more source

Life on a Mesoarchean marine shelf – insights from the world’s oldest known granular iron formation

Scientific Reports, 2020
The Nconga Formation of the Mesoarchean (~2.96–2.84 Ga) Mozaan Group of the Pongola Supergroup of southern Africa contains the world’s oldest known granular iron formation.
Albertus J. B. Smith, Nicolas J. Beukes, Jens Gutzmer, Clark M. Johnson, Andrew D. Czaja, Noah Nhleko, Frikkie de Beer, Jakobus W. Hoffman, Stanley M. Awramik   +8 more
doaj   +1 more source

Magma feeding paleochannel in the Monchegorsk ore region: geochemistry, isotope U-Pb and Sm-Nd analysis (Kola region, Russia)

Записки Горного института, 2022
A comprehensive study of a 340 m thick lenticular-sheet body of ultramafic composition penetrated by structural well M-1 at a depth of about 2.2 km was accomplished.
Valeriy F. Smolkin, Artem V. Mokrushin, Tamara B. Bayanova, Pavel A. Serov, Aleksey A. Ariskin   +4 more
doaj   +1 more source

Constraints on Paleoproterozoic atmospheric oxygen levels [PDF]

Proceedings of the National Academy of Sciences, 2018
Significance Earth’s protracted oxygenation significantly transformed global biological and geochemical cycles. In particular, the rise of atmospheric oxygen above trace levels was an essential prerequisite for the development of animals. However, quantifying atmospheric oxygen levels in Earth’s middle age remains a daunting challenge.
Eric J. Bellefroid, Ashleigh v. S. Hood, Paul F. Hoffman, Matthew D. Thomas, Christopher T. Reinhard, Noah J. Planavsky   +5 more
openaire   +2 more sources

Paleoproterozoic sterol biosynthesis and the rise of oxygen [PDF]

Nature, 2017
Natural products preserved in the geological record can function as 'molecular fossils', providing insight into organisms and physiologies that existed in the deep past. One important group of molecular fossils is the steroidal hydrocarbons (steranes), which are the diagenetic remains of sterol lipids.
Gold, David, Caron, Abigail, Fournier, Gregory P., Summons, Roger E   +3 more
openaire   +4 more sources

LITHOCHEMISTRY AND CONDITIONS OF SEDIMENTATION OF THE PALEOPROTEROZOIC IRON-SILICEOUS FOR-MATION OF THE KRIVOY ROG BASIN (UKRAINIAN SHIELD)

Геохімія техногенезу, 2020
Based on modern lithochemical dataset statistical processing methods, the chemical composition features of the Paleoproterozoic iron ore (iron-siliceous) formation of the Saksagan Formation of the Kryvyi Rig basin of the Ukrainian Shield have been ...
Pokalyuk V.
doaj   +1 more source

Paleoproterozoic Metamorphism of the Archean Tuntsa Suite, Northern Fennoscandian Shield [PDF]

, 2020
The Tuntsa Suite is a polymetamorphic Archean complex mainly consisting of metasedimentary gneisses. At least two strong metamorphic events can be distinguished in the area.
Huhma, Hannu, Butcher, Alan R., Rollinson, Gavyn, Kurhila, Matti, Hölttä, Pentti, Kivisaari, Tiia   +5 more
core   +2 more sources

CARBONATES OF ORE DEPOSITS OF PRECAMBRIAN OF THE CENTRAL PART OF THE UKRAINIAN SHIELD

Геохімія техногенезу, 2020
The article presents the results of study of the isotopic composition of oxygen and carbon of carbonates in ore deposits of the Early Pre-cambrian of the Ukrainian Shield. The following objects were studied: 1. Iron ore formations of the Kryvyi Rih ultra-
Fomin Yu., Demikhov Yu., Verkhovtsev V., Borisova N., Chuprinova S.   +4 more
doaj   +1 more source

Detrital zircon geochronology of Paleoproterozoic metasedimentary rocks from Jämsä, Central Finland [PDF]

Bulletin of the Geological Society of Finland
In this short communication, we present new detrital single grain zircon U-Pb data for six metasedimentary rock samples from Jämsä, Central Finland.
Perttu Mikkola, Matti Kurhila, Hannu Huhma   +2 more
doaj   +1 more source

Petrogenesis and tectonic significance of the Mengjiaping beschtauite in the southern Taihang mountains

Open Geosciences, 2021
The evolution process of the North China Craton has been discussed by many scholars; however, the frame for the timing of the Trans-North China Block has not been fully agreed upon.
Tian Haofei, Li Ganyu, Choi Jinyong, Luan Wenlou, Cui Xingtao, Wang Shen, Jin Mengqi, Chen Haotian, Chen Wenjing, Liang Xian, Zou Chengjie, Zhao Liang, Han Sinan, Zou Peijie, Hu Xiaofei   +14 more
doaj   +1 more source