scholarly journals The Geochemical and Isotopic Record of Wilson Cycles in Northwestern South America: From the Iapetus to the Caribbean

Geosciences ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 5
Author(s):  
Richard Spikings ◽  
Roelant Van der Lelij
Keyword(s):  
South America ◽  
Passive Margin ◽  
Large Igneous Province ◽  
Geochemical Data ◽  
Active Margin ◽  
Iapetus Ocean ◽  
Continental Arc ◽  
Wilson Cycle ◽  
The Caribbean ◽  
Back Arc

Isotopic and geochemical data delineate passive margin, rift and active margin cycles in northwestern South America since ~623 Ma, spanning from the Iapetus Wilson Cycle. Ultramafic and mafic rocks record rifting associated with the formation of the Iapetus Ocean during 623–531 Ma, while the initiation of subduction of the Iapetus and Rheic oceans is recorded by continental arc plutons that formed during 499–414 Ma, with alternating compressive and extensional stages. Muscovite 40Ar/39Ar dates suggest there may have been a phase of Carboniferous metamorphism, although this remains tentative. A Passive margin was modified by active margin magmatism that started at ~294 Ma and culminated with collisional tectonics that signaled the final stages of the amalgamation of western Pangaea. Early Pangaea fragmentation included back-arc rifting during 245–216 Ma, leading to a Pacific active margin that spanned from 213–115 Ma. Trench retreat accelerated during 144–115 Ma, forming a highly attenuated continental margin prior to the collision of the Caribbean Large Igneous Province at ~75 Ma.

Inversion of Taconian extensional structures during Paleozoic orogenesis in western Newfoundland

2018 ◽  
Vol 470 (1) ◽  
pp. 311-336 ◽  
Author(s):  
Shawna E. White ◽  
John W. F. Waldron
Keyword(s):  
Long Range ◽  
Foreland Basin ◽  
Passive Margin ◽  
Normal Faults ◽  
Middle Ordovician ◽  
Iapetus Ocean ◽  
Thrust Belts ◽  
Wilson Cycle ◽  
Flexural Bulge ◽  
Extensional Structures

AbstractWest Newfoundland was critical in developing the Wilson Cycle concept. Neoproterozoic rifting established a passive margin adjacent to the Iapetus Ocean. Ordovician (Taconian) arc–continent collision emplaced ophiolites and the thin-skinned Humber Arm Allochthon. Subsequent Devonian (Acadian) ocean closure produced basement-cutting thrust faults that control the present-day distribution of units. New mapping, and aeromagnetic and seismic interpretation, around Parsons Pond enabled the recognition of structures in poorly exposed areas.Following Cambrian to Middle Ordovician passive-margin deposition, Taconian deformation produced a flexural bulge unconformity. Subsequent extensional faults shed localized conglomerate into the foreland basin. The Humber Arm Allochthon contains a series of stacked and folded duplexes, typical of thrust belts. To the east, the Parsons Pond Thrust has transported shelf and foreland-basin units c. 8 km westwards above the allochthon. The Long Range Thrust shows major topographical expression but <1 km offset. Stratigraphic relationships indicate that most thrusts originated as normal faults, active during Neoproterozoic rifting, and subsequently during Taconian flexure. Devonian continental collision inverted the Parsons Pond and Long Range thrusts. Basement-cored fault-propagation folds in Newfoundland are structurally analogous to basement uplifts in other orogens, including the Laramide Orogen in western USA. Similar deep-seated inversion structures may extend through the northern Appalachians.

The geological history of northwestern South America: from Pangaea to the early collision of the Caribbean Large Igneous Province (290–75Ma)

2015 ◽  
Vol 27 (1) ◽  
pp. 95-139 ◽  
Author(s):  
Richard Spikings ◽  
Ryan Cochrane ◽  
Diego Villagomez ◽  
Roelant Van der Lelij ◽  
Cristian Vallejo ◽  
...  
Keyword(s):  
South America ◽  
Large Igneous Province ◽  
Geological History ◽  
Igneous Province ◽  
History Of ◽  
The Caribbean

Diachronous Paleozoic accretion of peri-Gondwanan terranes at the Laurentian margin

2018 ◽  
Vol 470 (1) ◽  
pp. 289-310 ◽  
Author(s):  
John W. F. Waldron ◽  
David I. Schofield ◽  
J. Brendan Murphy
Keyword(s):  
Modern Concept ◽  
Early Devonian ◽  
Provenance Data ◽  
Iapetus Ocean ◽  
Accreted Terranes ◽  
Wilson Cycle ◽  
Depositional Age ◽  
Laurentian Margin ◽  
Back Arc ◽  
Timing Of Arrival

AbstractIn the original Wilson cycle, the northern Appalachian–Caledonide orogen resulted from the collision of two continental masses separated by a single ocean. One of these corresponds to the modern concept of Laurentia, but the colliding continent to the east has been variously subdivided into many smaller terranes and domains, including Ganderia, Avalonia and Megumia. Using published stratigraphic evidence and detrital zircon provenance data from units of known depositional age, the timing of arrival of these units at the Laurentian margin between the Early Ordovician and Early Devonian can be constrained. Several of the accreted terranes do not extend over the entire length of the orogen, with the result that the lines separating them change character along strike from terrane-bounding sutures to simple accretionary faults. The Ganderia domain consists of at least four separate terranes that share a common origin on the continental margin of Gondwana, but were separated by back-arc oceanic crust as they crossed the Iapetus Ocean and collided diachronously with the Laurentian margin.

Collision of the Caribbean Large Igneous Province with the Americas: Earliest evidence from the forearc of Costa Rica

2019 ◽  
Vol 131 (9-10) ◽  
pp. 1555-1580 ◽  
Author(s):  
Goran Andjić ◽  
Peter O. Baumgartner ◽  
Claudia Baumgartner-Mora
Keyword(s):  
Costa Rica ◽  
North America ◽  
Large Igneous Province ◽  
Geochemical Data ◽  
Published Data ◽  
Valuable Insight ◽  
Oceanic Plateau ◽  
The Pacific ◽  
Igneous Province ◽  
The Caribbean

AbstractThe Cretaceous period was marked by the most voluminous episodes of oceanic plateau volcanism in the Phanerozoic Eon. Primarily affecting the Pacific, mantle plumes generated oceanic plateaus during three main phases (ca. 145–140 Ma, ca. 122–115 Ma, and ca. 100–90 Ma). Central America is one of the very few circum-Pacific margins where remnants of these Cretaceous plateaus were accreted. The study of their onland exposures provides a highly valuable insight into the complexity and diversity of oceanic plateau histories, from their eruption to their accretion. Exposed in northern Costa Rica, the plateau remnants of the Nicoya Peninsula originated from a Jurassic oceanic crust over-thickened by Early and Late Cretaceous hotspots. These sheared-off pieces of the Farallon Plate testify to the early tectonic interaction of the Caribbean Large Igneous Province (CLIP, ca. 94–89 Ma) with North America, initiated <5 m.y. after the onset of CLIP eruption. By combining our results with previously published data, we propose an updated tectono-stratigraphic framework that divides the Nicoya Peninsula into two oceanic plateau terranes. (1) The accretion timing of the Aptian to Turonian Manzanillo Terrane is constrained by the Coniacian (ca. 89–86 Ma) base of the overlapping Loma Chumico Formation. The proximal tuffaceous forearc deposits of the Loma Chumico Formation are the oldest evidence of a volcanic arc in Costa Rica—called here the Berrugate Arc—as revealed by new biostratigraphic and geochemical data. (2) The Nicoya Complex s. str. is a composite plateau remnant containing rocks of Bajocian to earliest Campanian age. Its accretion occurred during the middle Campanian (ca. 79–76 Ma) and shut down the Berrugate Arc. In contrast to the collision of CLIP with North America, onset of the collision of CLIP with South America began much later, during the latest Campanian (ca. 75–73 Ma).

scholarly journals Subduction history of the Caribbean from upper-mantle seismic imaging and plate reconstruction

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Benedikt Braszus ◽  
Saskia Goes ◽  
Rob Allen ◽  
Andreas Rietbrock ◽  
Jenny Collier ◽  
...  
Keyword(s):  
Upper Mantle ◽  
Large Igneous Province ◽  
Fracture Zones ◽  
Igneous Province ◽  
Wave Imaging ◽  
History Of ◽  
The Caribbean ◽  
Subducting Plate ◽  
Plate Reconstruction ◽  
Back Arc

AbstractThe margins of the Caribbean and associated hazards and resources have been shaped by a poorly understood history of subduction. Using new data, we improve teleseismic P-wave imaging of the eastern Caribbean upper mantle and compare identified subducted-plate fragments with trench locations predicted from plate reconstruction. This shows that material at 700–1200 km depth below South America derives from 90–115 Myr old westward subduction, initiated prior to Caribbean Large-Igneous-Province volcanism. At shallower depths, an accumulation of subducted material is attributed to Great Arc of the Caribbean subduction as it evolved over the past 70 Ma. We interpret gaps in these subducted-plate anomalies as: a plate window and tear along the subducted Proto-Caribbean ridge; tearing along subducted fracture zones, and subduction of a volatile-rich boundary between Proto-Caribbean and Atlantic domains. Phases of back-arc spreading and arc jumps correlate with changes in age, and hence buoyancy, of the subducting plate.

scholarly journals A re-appraisal of the petrogenesis and tectonic setting of the Ordovician Fishguard Volcanic Group, SW Wales

2015 ◽  
Vol 153 (3) ◽  
pp. 410-425 ◽  
Author(s):  
BETHAN A. PHILLIPS ◽  
ANDREW C. KERR ◽  
RICHARD BEVINS
Keyword(s):  
Fractional Crystallization ◽  
Tectonic Setting ◽  
Source Region ◽  
Geochemical Data ◽  
Spinel Lherzolite ◽  
Magma Chamber Processes ◽  
Volcanic Group ◽  
South Wales ◽  
Iapetus Ocean ◽  
Back Arc

AbstractThe Fishguard Volcanic Group represents an excellently preserved example of a volcanic sequence linked to the closure of the Iapetus Ocean. This study re-examines the petrogenesis and proposed tectonic setting for the Llanvirn (467–458 Ma) Fishguard Volcanic Group, South Wales, UK. New major and trace element geochemical data and petrographic observations are used to re-evaluate the magma chamber processes, mantle melting and source region. The new data reveal that the Fishguard Volcanic Group represents a closely related series of basalts, basaltic andesites, dacites and rhyolites originating from a spinel lherzolite source which had been modified by subduction components. The rocks of the Fishguard Volcanic Group are co-genetic and the felsic members are related to the more primitive basalts mainly by low-pressure fractional crystallization. The geochemistry of the lavas was significantly influenced by subduction processes associated with a coeval arc, while significant amounts of assimilation of continental crust along with fractional crystallization appear to have contributed to the compositions of the most evolved lavas. The Fishguard Volcanic Group was erupted into a back-arc basin where extensive rifting but no true seafloor spreading had occurred.

The Pre-Pan-African rifting of Saghro (Anti-Atlas, Morocco): example of the middle Neoproterozoic Basin of Boumalne

2002 ◽  
Vol 173 (1) ◽  
pp. 25-35 ◽  
Author(s):  
Abdelilah Fekkak ◽  
André Pouclet ◽  
Lakhlifi Badra
Keyword(s):  
Continental Margin ◽  
Detrital Zircons ◽  
Passive Margin ◽  
Lava Flows ◽  
Active Margin ◽  
Volcanic Arc ◽  
Chemical Signature ◽  
Pan African ◽  
Back Arc ◽  
Oceanic Domain

Abstract In the Anti-Atlas, the Boumalne basin includes 3,000 m of Middle Neoproterozoic sediments. It consists of turbiditic deposits folded during the major Pan-African event ca 685 Ma. A syn-sedimentary basaltic pile of lava flows is interbedded in the upper part of the lower formation. These lavas show an initial rift tholeiite (IRT) chemical signature. Petrographical analysis of sediments and typology of detrital zircons indicate a continental margin sedimentation, without any volcano-sedimentary supply from a close volcanic arc. It is concluded that the Boumalne Basin formed in a continental passive margin evolving from an intracontinental rift. This interpretation differs clearly from that of a back-arc basin which is commonly accepted. Hence, the opening of this basin is related to the pre-Pan-African Saghro rift synchronous to the Central Anti-Atlas oceanization, and not to the demise of this oceanic domain along an active margin.

The Margaree orthogneiss: an Ordovician, peri-Gondwanan, mafic-felsic igneous complex in southwestern Newfoundland

2000 ◽  
Vol 37 (12) ◽  
pp. 1691-1710 ◽  
Author(s):  
Pablo Valverde-Vaquero ◽  
Greg R Dunning ◽  
Cees R van Staal
Keyword(s):  
Country Rock ◽  
Amphibolite Facies ◽  
Passive Margin ◽  
Granitic Magma ◽  
Volcanic Arc ◽  
Rock Types ◽  
Regional Deformation ◽  
Iapetus Ocean ◽  
Synkinematic Granite ◽  
Back Arc

The igneous protoliths of the Margaree orthogneiss intruded the peri-Gondwanan rocks of the Port-aux-Basques Complex, in the southwestern corner of the Hermitage Flexure, prior to regional deformation and metamorphism. Field relationships and U–Pb geochronology indicate that the Margaree orthogneiss represents a 20 km long, mafic-felsic intrusive complex formed by amphibolite, dioritic orthogneiss, 474+14-4 Ma hornblende-bearing tonalitic orthogneiss with mafic enclaves, 472 ± 2.5 Ma and 465 ± 3 Ma biotite-bearing granitic orthogneiss, and minor ultramafic rocks. Most amphibolite have the chemistry of volcanic-arc tholeiite and are interpreted to be coeval with the intrusion of tonalitic and granitic magma with volcanic-arc geochemical signatures. Locally, mafic magmatism continued after the intrusion of the 465 Ma granite. The Margaree orthogneiss and its country rock were overprinted by upper amphibolite-facies metamorphism and deformation associated with the final closure of the Iapetus Ocean. A late-synkinematic granite dates the late stages of the high-temperature regional deformation at 417+7-4 Ma, while metamorphic titanite (411 ± 2 Ma) is interpreted to date extensive recrystallization under amphibolite-facies conditions as Early Devonian. The Margaree orthogneiss is broadly coeval with the plutons that postdate the Early Ordovician Penobscottian arc – passive margin imbrication in central and southern Newfoundland. It also coincides with the extensive late Arenig – early Llanvirn back-arc rifting event along the entire peri-Gondwanan margin of the northern Appalachians. The external position of the Port-aux-Basques Complex with respect to the back-arc elements in the Hermitage Flexure, coupled with the rock types and geochemistry of the orthogneiss, suggest formation of the Margaree orthogneiss in an arc and (or) back-arc transitional setting.

Animal taxa named for Rollo H. Beck

2014 ◽  
Vol 41 (1) ◽  
pp. 113-123 ◽  
Author(s):  
Gary M. Fellers
Keyword(s):  
Natural History ◽  
South America ◽  
Southern California ◽  
American Museum ◽  
Type Specimens ◽  
California Academy ◽  
Vertebrate Zoology ◽  
The Caribbean ◽  
Set Up ◽  
Academy Of Sciences

Rollo Howard Beck (1870–1950) was a professional bird collector who spent most of his career on expeditions to the Channel Islands off southern California, the Galápagos Islands, South America, the South Pacific, and the Caribbean. Some of the expeditions lasted as long as ten years during which time he and his wife, Ida, were often working in primitive conditions on sailing vessels or camps set up on shore. Throughout these expeditions, Beck collected specimens for the California Academy of Sciences, the Museum of Vertebrate Zoology at Berkeley (California), the American Museum of Natural History, and the Walter Rothschild Museum at Tring, England. Beck was one of the premier collectors of his time and his contributions were recognized by having 17 taxa named becki in his honor. Of these taxa, Beck collected 15 of the type specimens.

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