Pablo Valverde-Vaquero | Geological Survey of Spain-Instituto Geológico de España (IGME) (original) (raw)

Papers by Pablo Valverde-Vaquero

Solid Earth Discussions, 2015

High-grade highly deformed gneisses crop out continuously along the Masanteo peninsula in the Cab... more High-grade highly deformed gneisses crop out continuously along the Masanteo peninsula in the Cabo Ortegal nappe (NW Spain). The rock sequence formed by quartzo-feldspathic gneisses and mafic rocks records two partial melting events: during the Early Ordovician (ca. 480–488 Ma.), at the base of the Qz-Fsp gneisses, and immediately after eclogization (ca. 390.4 ± 1.2 Ma), during its early Variscan exhumation. Despite the strain accumulated during their final exhumation in which a pervasive blastomylonitic S<sub>2</sub> foliation was developed, primary sedimentary layering in Qz-Fsp gneisses is well preserved locally at the top of the sequence. This first stage of the exhumation process occurred in ~ 10 Ma, during which bulk flattening of the high-grade rock sequence was accommodated by anastomosing shear bands that evolved to planar shear zones. Strain was progressively localized along the boundaries of the migmatitic Qz-Fsp gneisses. A SE-vergent ductile thrust constitut...

International Geology Review

Geologica Acta, 2005

The northern termination of the Schistose Domain of the Galicia-Tras-os-Montes Zone is a tectonic... more The northern termination of the Schistose Domain of the Galicia-Tras-os-Montes Zone is a tectonic slice named the Rio Baio Thrust Sheet, which is sandwiched between the Cabo Ortegal Complex and the Ollo de Sapo Domain of the Central-Iberian Zone. The Rio Baio Thrust Sheet is formed by two volcanosedimentary series, the Loiba and the Queiroga Series. The Loiba Series contains calc-alkaline dacite and rhyolite, while the overlying Queiroga Series has alkaline rhyolite. These series were considered to be in stratigraphically upwards continuity and believed to be Silurian in age. U-Pb dating of an alkaline rhyolite in the Queiroga Series provides an Arenig age of 475 ± 2 Ma. This age makes the Queiroga Series the oldest known stratigraphic unit in the Schistose Domain of the Galicia-Tras-os-Montes Zone, impeding correlation between the lithostratigraphic sequences of Ortegal and Central Galicia. As well as providing evidence of an unforeseen structural complexity within the Rio Baio She...

Geologica Acta, 2017

The El Crispinejo granite forms part of a small, but distinctive late intrusive suite of cordieri... more The El Crispinejo granite forms part of a small, but distinctive late intrusive suite of cordierite-bearing peraluminous granites in the South Portuguese Zone (SPZ). This granite has the best outcrop relationships of the suite. It cross-cuts different members of the Sierra Norte Batholith of the SPZ and the Carboniferous Volcano-Sedimentary Complex of the Iberian Pyrite Belt, producing contact metamorphism. This late pluton has a high K content which results in a contrasting geophysical response (K-Th-U) with respect to the surrounding trondhjemitic granitoids of the TTG suite of the Sierra Norte Batholith. A concordant monazite-zircon U-Pb ID-TIMS age of 300.5 +0.5/-1.5Ma demonstrates Permo-Carboniferous age for this late Variscan magmatic event. The granite is associated with a series of ore showings (F-Pb-Zn and Sn-W) which are completely different from the nearby, massive sulphide and manganese ore deposits of the Iberian Pyrite Belt, indicating the unique character of this intr...

The Cinq-Cerf gneiss represents one of the oldest tectonic elements yet documented within the “Av... more The Cinq-Cerf gneiss represents one of the oldest tectonic elements yet documented within the “Avalonian” basement complex of the Hermitage Flexure region of the Newfoundland Appalachians. This gneiss is a composite unit that includes both supra-crustal and granitic gneisses, the latter having an igneous crystallization age of 675+12/−11Ma. The timing of the gneiss-forming event (D1 polyphase deformation) is constrained by

Atlantic Geology, 2009

Detrital zircon ages were determined for conglomerate and sandstone samples from six fault-bounde... more Detrital zircon ages were determined for conglomerate and sandstone samples from six fault-bounded belts in New Brunswick and coastal Maine. Formations sampled included the Martinon (Brookville belt), Flagg Cove (Grand Manan Island belt), Matthews Lake (New River belt), Ellsworth (Ellsworth belt), Calais (St. Croix belt), and Baskahegan Lake (Miramichi belt). Their maximum age of deposition is based on the youngest detrital zircon population and minimum age of deposition based on stratigraphic, paleontological, and cross-cutting intrusive relationships. The determined range of depositional ages are: Martinon between 602 ± 8 (youngest zircons) and 546 ± 2 Ma (age of cross-cutting intrusion); Flagg Cove between 574 ± 7 (youngest zircons) and 535 ± 3 Ma (age of cross-cutting intrusion); Matthews Lake between 539 ± 5 (youngest zircons) and 514 ± 2 Ma (age of overlying volcanic rocks); Ellsworth between 507 ± 6 (youngest zircons) and 504 ± 3 Ma (age of overlying volcanic rocks); Calais b...

The Central Mobile Belt of Newfoundland Appalachians records the Ordovician arc - arc collision b... more The Central Mobile Belt of Newfoundland Appalachians records the Ordovician arc - arc collision between the peri-Laurentian Red Indian Lake Arc of the Annieopsquotch accretionary tract (c. 480-460 Ma), and the peri- Gondwanan Victoria - Popelogan Arc (c. 473-453 Ma), which marks the closure of the Cambro-Ordovician Iapetus Ocean. Although the arc systems are in part coeval, they are distinguishable

Precambrian Research, 2002

Journal of the Geological Society, 2000

ABSTRACT

Geological Society, London, Special Publications, 2009

During the Early to Middle Palaeozoic, prior to formation of Pangaea, the Canadian and adjacent N... more During the Early to Middle Palaeozoic, prior to formation of Pangaea, the Canadian and adjacent New England Appalachians evolved as an accretionary orogen. Episodic orogenesis mainly resulted from accretion of four microcontinents or crustal ribbons: Dashwoods, Ganderia, Avalonia and Meguma. Dashwoods is peri-Laurentian, whereas Ganderia, Avalonia and Meguma have Gondwanan provenance. Accretion led to a progressive eastwards (present co-ordinates) migration of the onset of collision-related deformation, metamorphism and magmatism. Voluminous, syn-collisional felsic granitoid-dominated pulses are explained as products of slab-breakoff rather than contemporaneous slab subduction. The four phases of orogenesis associated with accretion of these microcontinents are known as the Taconic, Salinic, Acadian and Neoacadian orogenies, respectively. The Ordovician Taconic orogeny was a composite event comprising three different phases, due to involvement of three peri-Laurentian oceanic and co...

Canadian Journal of Earth Sciences, 2000

The igneous protoliths of the Margaree orthogneiss intruded the peri-Gondwanan rocks of the Port-... more 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 UPb 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 ...

Preliminary results of fieldwork in the Victoria Lake–Peter Strides Pond area indicate that a hig... more Preliminary results of fieldwork in the Victoria Lake–Peter Strides Pond area indicate that a high-strain zone, the Victoria Lake shear zone, separates low-grade tectonites of the Exploits Subzone from medium- to high-grade tectonites (stauro lite to sillimanite + K-feldspar zone). These metamorphic tectonites include a band having rocks typical of the Exploits Subzone, i.e., the Howley Waters belt. Amalgamation of the Howley Waters belt with the Meelpaeg Subzone took place before peak regional metamorphism. The development of the Victoria Lake shear zone took place during the D2 deformation and coincides with peak metamorphism in the staurolite zone. The shear zone shows progressive change in trend, dip and motion from a reverse southeast-dipping fault in the southwest to a north-dipping normal fault in the central sector and back to a southeast-dipping reverse fault in the east.

An integrated field and analytical study of three areas in Newfoundland and Spain was carried out... more An integrated field and analytical study of three areas in Newfoundland and Spain was carried out to investigate the extent of the linkage between the geological evolution of the Peri-Gondwanan margin of the Iapetus Ocean, recorded in the southwest Hermitage Flexure of the Newfoundland Appalachians, and that of the Sierra de Guadarrama in the Central Iberian Zone of the Iberian Massif (European Variscan Belt). This study, while resolving the timing and character of the respective Appalachian and Variscan overprints, highlights the major importance of the Early Ordovician (ca. 480-470 Ma) magmatic events. -- The Cinq-Cerf gneiss is part of the westernmost extent of the Late Precambrian basement block of the Hermitage Flexure. New data from the Cinq-Cerf gneiss demonstrates that this is a composite unit formed by highly strained metasedimentary rocks and 675+12/-11 Ma granitic orthogneiss, locally intruded by weakly defomed 584+7/-6 Ma Hb1-bearing granodiorite and a transitional/volca...

The Cinq-Cerf gneiss is part of the westernmost extent of the Late Precambrian-Early Ordovician b... more The Cinq-Cerf gneiss is part of the westernmost extent of the Late Precambrian-Early Ordovician basement block of the Hermitage Flexure. U-Pb ages from the previously undated Cinq-Cetf gneiss provide a strong link with the Precambrian rocks of Grey River (Hermitage Flexure) and the Connaigre peninsula (Avalon Zone s.s. ). The youngest unit in the Cinq-Cerf complex is a variably defonned 431.5 ± 1 Ma granite-granodiorite with amplubolite and gneissic enclaves, cross-cut by mafic dykes deformed in upper greenschist facies (420 Ma, titanite). Syn-magmatic deformation followed by variable greenschist facies mylonitization mimic a high-grade gneissic complex. The 431 Ma granite intruded into older rocks, including weakly deformed metagabbro/diorite (557+14/-5 Ma) and homblendebearing granodiorite (584+ 7 /-6 Ma). The gneissic fabric in a highly strained 675+ 12/-11 Ma granitic orthogneiss is crosscut by the 431 Ma granite. This observation, coupled with the preservation of primacy magmat...

L.R. Fyffe1, S.M. Barr2, S.C. Johnson3, M.J. McLeod3, V.J. McNicoll4, P. ValverdeVaquero5, C.R. v... more L.R. Fyffe1, S.M. Barr2, S.C. Johnson3, M.J. McLeod3, V.J. McNicoll4, P. ValverdeVaquero5, C.R. van Staal6, and C.E.White7 1. Geological Surveys Branch, New Brunswick Department of Natural Resources, Fredericton, NB, Canada E3B 5H1 ¶ 2. Department of Earth and Environmental Science, Acadia University, Wolfville, NS, Canada B4P 2R6 ¶ 3. Geological Surveys Branch, New Brunswick Department of Natural Resources, Sussex, NB, Canada E4E 5L2 ¶ 4. Geological Survey of Canada, Ottawa, ON, Canada K1A OE8 ¶ 5. Instituto Geologico y Minero de Espana, La Calera 1, Tres Cantos, Madrid, Spain ¶ 6. Geological Survey of Canada (Pacific), Vancouver, BC, Canada V6B 5J3 ¶ 7. Nova Scotia Department of Natural Resources, Halifax, NS, Canada B3J 2T9