Results 51 to 60 of about 16,578 (144)

Criteria for the recognition of metamorphosed or altered lamprophyres: A case study from the Archaean of Kambalda, Western Australia

, 1989
The ability to distinguish ancient lamprophyres from other mafic and ultramafic intrusive rock types has become increasingly important. Lamprophyres have been used as marker horizons in the mapping of several Precambrian terranes, they have been ...
Rock, Nicholas M.S., Perring, Caroline S., Roberts, David E., Golding, Suzanne D.   +3 more
core   +1 more source

Petrogenesis of melanite-garnets in monzodiorites from SW of Jandaq (NW of Central-East Iranian Microcontinent)

Journal of Economic Geology
The Godar-e-Siah Eocene monzodiorite stock is located in the southwest of the Jandaq area (NE of Isfahan) and northwest of the Central-East Iranian Microcontinent (CEIM). The main minerals in these monzodiorites are plagioclase, K-feldspar, clinopyroxene,
Ahmad Jamshidzaei, Khadijeh Khalili, Ghodrat Torabi   +2 more
doaj   +1 more source

Cold Deep Over Hot Shallow Crust: A Peculiar Metamorphic Architecture in the Neoarchean Metasedimentary Pontiac Subprovince, Superior Craton (Canada)

Journal of Metamorphic Geology, Volume 43, Issue 2, Page 191-224, February 2025.
ABSTRACT The Neoarchean Era is a key period in Earth's history as it witnessed a significant pulse of crustal formation corresponding to the assembly of several cratons, potentially coeval with a transition in the global tectonic regime. Neoarchean metasedimentary subprovinces of the Superior Craton, the largest unreworked Archean craton on Earth, were
Isaac S. Malta, Carl Guilmette, Antoine Godet, Douglas K. Tinkham, Bruna Coldebella, Georges Beaudoin, Crystal LaFlamme, Taus R. C. Jørgensen, Jeffrey H. Marsh   +8 more
wiley   +1 more source

Cold Tectonics of Kos, Central Dodecanese: Oligocene Bivergent Extension of the Pelagonian Domain

Tectonics, Volume 43, Issue 12, December 2024.
Abstract Tectonic and lithological correlations between the Cycladic Blueschist Unit of the Aegean domain and Pelagonian domain of the western Turkey have rarely been proposed. Herein, we focus on the pre‐volcanic geology of Kos, and investigate the tectonic history of the central Dodecanese Islands and the general correlation between the two domains ...
Vincent Roche, Bernhard Grasemann, David Schneider, Konstantinos Soukis, Michael Pichler   +4 more
wiley   +1 more source

Some notes on the IUGS classification of lamprophyric rocks

Mineralogia
The lamprophyric rocks are uncommon volatile-rich melanocratic porphyritic rocks which contain only mafic phenocrysts. The felsic minerals are confined in the groundmass. They occur as dikes, sills and diatremes.
Kamvisis Ioannis, Phani Pothuri Ramesh Chandra   +1 more
doaj   +1 more source

Basanite cobbles in Pleistocene sediments in Central Otago and their implications for intraplate volcanism and Clutha River paleo‐drainage

New Zealand Journal of Geology and Geophysics, Volume 67, Issue 4, Page 451-466, December 2024.
ABSTRACT The occurrence of volcanic basanite cobbles in Pleistocene terraces at Galloway and in the upper Clutha valley in Central Otago, in an area devoid of known volcanic edifices, has implications for Cenozoic intraplate volcanism and Pleistocene drainage in the region.
James M. Scott, Alan F. Cooper, Dave Craw, Petrus J. le Roux, Hayden B. Dalton, Marshall C. Palmer   +5 more
wiley   +1 more source

3‐D Subsurface Geophysical Modeling of the Charity Shoal Structure: A Probable Late Proterozoic‐Early Paleozoic Simple Impact Structure in Eastern Lake Ontario

Earth and Space Science, Volume 11, Issue 11, November 2024.
Abstract The Charity Shoal structure is a circular, ∼1.2‐km‐diameter, bedrock‐rimmed shoal in eastern Lake Ontario with a ∼20‐m‐deep central basin. The structure has been proposed as a possible Middle Ordovician impact crater or volcanic intrusion. We conducted marine seismic and magnetic surveys (9‐km2) and 3‐D geophysical modeling to better resolve ...
Mary H. Armour, Joseph I. Boyce, Phillip Suttak, Doug Hrvoic   +3 more
wiley   +1 more source

Pretogenesis of Devonian lamprophyre and carbonatite minor intrusions, Kandalaksha Gulf (Kola Peninsula, Russia)

, 1996
Minor magmatic intrusions (dykes and explosion pipes) of lamprophyric and carbonatitic compositions occur on several islands in the Gulf of Kandalaksha (White Sea, Kola Peninsula, Russia).
Vetrin, V., Kempton, P.D., Beard, Andrew, Downes, Hilary, Maluski, H., H. Downes, H. Maluski, A.D. Beard, V. Vetrin, P.D. Kempton   +9 more
core   +1 more source

Middle Proterozoic ultramafic lamprophyre dykes in the Archaean of the Atâ area, central West Greenland

Rapport Grønlands Geologiske Undersøgelse, 1989
During the mapping of gneisses and supracrustal rocks around Eqe in the eastern part of the Atâ area in 1988 a series of ultramafic dykes of lamprophyric affinity were discovered by the authors. The dykes are conspicuous in the field because of their lithology, with often high contents of carbonate, and the occurrence of brownish phlogopite phenocrysts.
M Marker, C Knudsen
openaire   +2 more sources

Structures and Magmatism Associated With a Failed Triple Junction in Traill Ø, East Greenland

Tectonics, Volume 43, Issue 9, September 2024.
Abstract The Late Eocene–Oligocene post‐breakup magmatism of the North Atlantic Igneous Province (NAIP) in East Greenland, is represented by sub‐volcanic intrusions associated with a NE‐SW oriented magmatic lineament, the Werner Bjerge Rift. This onshore magmatism extends for more than 100 km from eastern Traill Ø to Werner Bjerge.
Pierpaolo Guarnieri, Christian Tegner, Charles K. Brooks   +2 more
wiley   +1 more source