Suturing Gondwana in the Cambrian: The Orogenic Events of the Final Amalgamation

2018 ◽  
pp. 411-432 ◽  
Author(s):  
Renata da Silva Schmitt ◽  
Rafael de Araújo Fragoso ◽  
Alan Stephen Collins
Keyword(s):  
Orogenic Events

Mesozoic Tectonomagmatic Evolution and Gold Metallogeny in Jiaodong Area, East China

2014 ◽  
Vol 905 ◽  
pp. 92-95 ◽  
Author(s):  
Xue Feng Yu ◽  
Da Peng Li ◽  
Hong Kui Li ◽  
Shu Xing Wang ◽  
Wei Shan
Keyword(s):  
Classification Scheme ◽  
Gold Mineralization ◽  
Alkali Feldspar ◽  
East China ◽  
Granite Emplacement ◽  
Miarolitic Cavity ◽  
The Pacific ◽  
Yanshan Movement ◽  
Orogenic Events

There were twice major collision orogenic events in Jiaodong area in Mesozoic period. It showed as three times of magmatic activities and stretching in Jiaodong area. In this paper, based on collecting age datas, referring to the previous classification scheme, a chronological frame pattern of Yanshanian granites had been put forward: Linglong-Kunyushan granite emplacement was in in 160~150Ma; the formation of Guojialing granodiorite was in 130~126Ma; Weideshan granodiorite-granite emplacement was in 120~110Ma; Laoshan A-type miarolitic cavity parlkaline alkali feldspar granite emplacement was in 110~100Ma and represented the end of Yanshan movement. Gold mineralization in three periods in this area had coupled relation with Linglong-Kunyushan granite, Guojialing granodiorite and Weideshan granodiorite-granite. Jiaodong tectonic-magmatic events and gold mineralization were controlled by the interactions among Tethyan tectonic domain, Paleo-ocean tectonic domain and the Pacific tectonic domain.

scholarly journals Constraints on the timing and duration of orogenic events by combined Lu–Hf and Sm–Nd geochronology: An example from the Grenville orogeny

2018 ◽  
Vol 501 ◽  
pp. 152-164 ◽  
Author(s):  
Thomas A. Johnson ◽  
Jeffrey D. Vervoort ◽  
Molly J. Ramsey ◽  
John N. Aleinikoff ◽  
Scott Southworth
Keyword(s):  
Grenville Orogeny ◽  
Orogenic Events

scholarly journals Unravelling the lithospheric-scale thermal field of the North Patagonian Massif plateau (Argentina) and its relations to the topographic evolution of the area

2020 ◽  
Author(s):  
Maria Laura Gomez Dacal ◽  
Magdalena Scheck-Wenderoth ◽  
Eugenio Aragón ◽  
Judith Bott ◽  
Mauro Cacace ◽  
...  
Keyword(s):  
Average Height ◽  
The North ◽  
Current State ◽  
Heating Event ◽  
Internal Deformation ◽  
Surrounding Areas ◽  
Transient Thermal ◽  
Thermal Simulations ◽  
Topographic Evolution ◽  
Orogenic Events

AbstractThe North Patagonian Massif (NPM) area in Argentina includes a plateau of 1200 m a.s.l. (meters above sea level) average height, which is 500–700 m higher than its surrounding areas. The plateau shows no evidence of internal deformation, while the surrounding basins have been deformed during Cenozoic orogenic events. Previous works suggested that the plateau formation was caused by a lithospheric uplift event during the Paleogene. However, the causative processes responsible for the plateau origin and its current state remain speculative. To address some of these questions, we carried out 3D lithospheric-scale steady-state and transient thermal simulations of the NPM and its surroundings, as based on an existing 3D geological model of the area. Our results are indicative of a thicker and warmer lithosphere below the NPM plateau compared with its surroundings, suggesting that the plateau is still isostatically buoyant and thus explaining its present-day elevation. The transient thermal simulations agree with a heating event in the mantle during the Paleogene as the causative process leading to lithospheric uplift in the region and indicate that the thermo-mechanical effects of such an event would still be influencing the plateau evolution today. Although the elevation related to the heating would not be enough to reach the present plateau topography, we discuss other mechanisms, also connected with the mantle heating, that may have caused the observed relief. Lithosphere cooling in the plateau is ongoing, being delayed by the presence of a thick crust enriched in radiogenic minerals as compared to its sides, resulting in a thermal configuration that has yet to reach thermodynamic equilibrium.

scholarly journals U–Pb zircon geochronology and phase equilibria modelling of HP-LT rocks in the Ossa-Morena Zone, Portugal

2020 ◽  
Vol 109 (8) ◽  
pp. 2719-2738
Author(s):  
Ismay Vénice Akker ◽  
Lucie Tajčmanová ◽  
Fernando O. Marques ◽  
Jean-Pierre Burg
Keyword(s):  
Phase Equilibria ◽  
Geodynamic Evolution ◽  
Mafic Rocks ◽  
Tholeiitic Magma ◽  
Metamorphic History ◽  
Metamorphic Temperature ◽  
Minimum Age ◽  
Higher Temperature ◽  
Geochemical Analyses ◽  
Orogenic Events

Abstract The Ossa-Morena Zone (OMZ) has a complex geological history including both Cadomian and Variscan orogenic events. Therefore, the OMZ plays an important role in understanding the geodynamic evolution of Iberia. However, the P–T–t evolution of the OMZ is poorly documented. Here, we combine structural and metamorphic analyses with new geochronological data and geochemical analyses of mafic bodies in Ediacaran metasediments (in Iberia known as Série Negra) to constrain the geodynamic evolution of the OMZ. In the studied mafic rocks, two metamorphic stages were obtained by phase equilibria modelling: (1) a high-pressure/low-temperature event of 1.0 ± 0.1 GPa and 470–510 °C, and (2) a medium-pressure/higher-temperature event of 0.6 ± 0.2 GPa and 550–600 °C. The increase in metamorphic temperature is attributed to the intrusion of the Beja Igneous Complex (around 350 Ma) and/or the Évora Massif (around 318 Ma). New U–Pb dating on zircons from the mafic rocks with tholeiitic affinity yields an age between 815 and 790 Ma. If the zircons crystallised from the tholeiitic magma, their age would set a minimum age for the pre-Cadomian basement. The ca. 800 Ma protolith age of HP-LT tholeiitic dykes with a different metamorphic history than the host Série Negra lead us to conclude that: (1) the HP-LT mafic rocks and HP-LT marbles with dykes were included in the Ediacaran metasediments as olistoliths; (2) the blueschist metamorphism is older than 550 Ma (between ca. 790 Ma and ca. 550 Ma, e.g., Cadomian).

scholarly journals Multi-chronometer dating of the Souter Head complex: rapid exhumation terminates the Grampian Event of the Caledonian Orogeny

2020 ◽  
Vol 111 (2) ◽  
pp. 95-108
Author(s):  
Darren F. MARK ◽  
Clive M. RICE ◽  
Malcolm HOLE ◽  
Dan CONDON
Keyword(s):  
Ductile Deformation ◽  
Volcanic Complex ◽  
Basic Magmatism ◽  
Peak Metamorphism ◽  
Caledonian Orogeny ◽  
Western Ireland ◽  
Decompressional Melting ◽  
Metamorphic Core ◽  
Orogenic Events ◽  
Rapid Uplift

ABSTRACTThe Souter Head sub-volcanic complex (Aberdeenshire, Scotland) intruded the high-grade metamorphic core of the Grampian Orogen at 469.1 ± 0.6 Ma (uranium-238–lead-206 (238U–206Pb) zircon). It follows closely peak metamorphism and deformation in the Grampian Terrane and tightly constrains the end of the Grampian Event of the Caledonian Orogeny. Temporally coincident U–Pb and argon/argon (40Ar/39Ar) data show the complex cooled quickly with temperatures decreasing from ca.800 °C to less than 200 °C within 1 Ma. Younger rhenium–osmium (Re–Os) ages are due to post-emplacement alteration of molybdenite to powellite. The U–Pb and Ar/Ar data combined with existing geochronological data show that D2/D3 deformation, peak metamorphism (Barrovian and Buchan style) and basic magmatism in NE Scotland were synchronous at ca.470 Ma and are associated with rapid uplift (5–10 km Ma−1) of the orogen, which, by ca.469 Ma, had removed the cover to the metamorphic pile. Rapid uplift resulted in decompressional melting and the generation of mafic and felsic magmatism. Shallow slab break-off (50–100 km) is invoked to explain the synchroneity of these events. This interpretation implies that peak metamorphism and D2/D3 ductile deformation were associated with extension. Similarities in the nature and timing of orogenic events in Connemara, western Ireland, with NE Scotland suggest that shallow slab break-off occurred in both localities.

scholarly journals Diagenetic apatite character and in situ ion microprobe U–Pb age, Keeseville Formation, Potsdam Group, New York State

2017 ◽  
Vol 54 (7) ◽  
pp. 785-797 ◽  
Author(s):  
Quentin Gall ◽  
William J. Davis ◽  
David G. Lowe ◽  
Quinn Dabros
Keyword(s):  
New York ◽  
Fluid Flow ◽  
New York State ◽  
Ion Microprobe ◽  
Crystal Length ◽  
Aeolian Processes ◽  
York State ◽  
Orogenic Events ◽  
Obvious Source

An occurrence of diagenetic fluorapatite cement is documented within the Cambro-Ordovician Keeseville Formation, Potsdam Group, near Chateaugay in New York State. The fluorapatite cement occurs as stratiform layers within ephemeral fluvial quartz arenites, which have been reworked by aeolian processes prior to burial. The paragenetic sequence includes the following: compaction of dust-rimmed grains → quartz cementation → minor kaolinite → fluorapatite cementation followed by secondary dissolution porosity and telogenetic hematite cementation. Mesogenetic illitization of kaolinite may have taken place prior to or following fluorapatite cementation. The fluorapatite occurs as elongated bladed crystals that characteristically contain ladder-like, inclusion-rich cores running parallel to crystal length, surrounded by clearer rims, and larger blocky crystals towards the middle of interstices. In situ SHRIMP analyses of blocky fluorapatite crystals yield a U–Pb age of 486 ± 29 Ma, indicating that the cement formed during mesogenetic burial processes and (or) during fluid flow driven by Taconic orogenic events. There is no obvious source of phosphorous for the fluorapatite cement within the Potsdam Group, but phosphorous-rich lithologies are known from the adjacent basement of the Adirondack Dome. Phosphorous-rich fluids may have been derived from these basement lithologies. The occurrence of the rare fluorapatite cement in the Keeseville Formation adjacent to the Chateaugay Lake Fault raises the possibility that alkaline phosphatic fluids were focused within the fault and migrated laterally away from the fault into the host Keeseville Formation to form stratiform fluorapatite cement in the sandstone.

Discussion and Reply: Timing of orogenic events in the Lachlan Orogen

2000 ◽  
Vol 47 (4) ◽  
pp. 813-822 ◽  
Author(s):  
D. A. Foster ◽  
D. R. Gray ◽  
A. H. M. Vandenberg
Keyword(s):  
Lachlan Orogen ◽  
Orogenic Events

Silurian fossils from western Spitsbergen

1976 ◽  
Vol 113 (6) ◽  
pp. 519-523 ◽  
Author(s):  
C. T. Scrutton ◽  
W. T. Horsfield ◽  
W. B Harland
Keyword(s):  
Orogenic Events

SummarySilurian fossils have been identified from Oscar II Land, western Spitsbergen. They are the first Silurian fossils recorded from Spitsbergen, and throw new light on regional correlations and the dating of Palaeozoic orogenic events in the region.

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