Search results for "amor"

METAMORPHIC EVOLUTION OF SPESSARTINE QUARTZITES (COTICULES) IN THE HIGH-PRESSURE, LOW-TEMPERATURE COMPLEX AT BAHIA MANSA, COASTAL CORDILLERA OF SOUTH…

2001

Lenses of spessartine quartzites (coticules) are associated with greenschist intercalations in coastal exposures at Bahia Mansa within the mainly metapsammopelitic Western Series, which forms most of the basement in the Coastal Cordillera of central to southern Chile. The chemical compositions of the coticules can be explained by protoliths formed from ferriferous and manganiferous hydrothermal precipitates mixed with aluminous alteration-derived material on top of oceanic crust. The peak conditions of metamorphism were calculated with multivariant reactions: 270–370 °C, 6–8 kbar. A retrograde P–T evolution was marked by decompression to 2 kbar during cooling below 300°C, influx of an exter…

Omphacite textures in eclogites of the Tauern Window: Implications for the exhumation of the Eclogite Zone, Eastern Alps

2008

Abstract We discuss the relationship of omphacite lattice preferred orientation (LPO) patterns in eclogite and kinematic indicators in the matrix surrounding the eclogite during the very rapid exhumation of the deeply buried Eclogite Zone in the Tauern Window of the Eastern Alps. LPO patterns are presented from profiles parallel to the eclogite stretching lineation across the Eclogite Zone. The omphacite textures show symmetric patterns across the entire Eclogite Zone; only in few cases slight asymmetries are observed. The patterns are characterized by an alignment of {110} with the foliation and a maximum of 〈001〉 close to the lineation and are indicative of deformation by intracrystalline…

2001

The roles of volume loss, coaxial versus noncoaxial flow, and blueschist exhumation in subduction-related accretionary wedges are still poorly understood. In our study at Leech Lake Mountain in the Eastern belt of the Franciscan subduction complex, we focus on these subjects. In the specific example of the Franciscan, the tectonic significance of the boundary between the Eastern and Central belts remains controversial. The Leech Lake Mountain area in northern California is situated immediately above this boundary and, therefore, appears to be of crucial importance for understanding aspects of the tectonic evolution of the Franciscan. The structural development at Leech Lake Mountain is char…

Miocene high-pressure metamorphism in the Cyclades and Crete, Aegean Sea, Greece: Evidence for large-magnitude displacement on the Cretan detachment

2001

The Cyclades in the backarc region of the present Hellenic subduction zone are known for widespread Late Cretaceous to Eocene high-pressure metamorphism in the Cycladic blueschist unit. We report 40 Ar/ 39 Ar and Rb/Sr phengite ages of 24–21 Ma for high- pressure metamorphism (8–10 kbar, 350–400 °C) in the lowest tectonic unit in the Cyclades, the Basal unit, which structurally underlies the Cycladic blueschist unit. The Basal unit is correlated with the Tripolitza unit of the External Hellenides in the forearc region of the Hellenic subduction zone. The Tripolitza unit is unmetamorphosed on Crete, where it is separated from the underlying high-pressure (8–10 kbar, 300–400 °C) Plattenkalk a…

Horizontal contraction or horizontal extension? Heterogeneous Late Eocene and early Oligocene general shearing during blueschist and greenschist faci…

1995

Mylonitic structures related to two orogenic events are described from the upper and lower contacts of the Combin zone and the immediately overlying upper Austroalpine Dent Blanche nappe/Mont Mary klippe and the directly underlying lower Austroalpine Etirol-Levaz slice. The first event, Late Eocene in age, commenced during blueschist facies P-T conditions, but pre-dated the peak of subsequent greenschist facies overprint. The second event, Early Oligocene in age, took place during retrograde greenschist facies conditions. Most sense of shear indicators associated with the retrograde mylonites indicate top SE shearing, but subordinate top NW displacing shear sense indicators have also been m…

From intra-oceanic subduction to arc accretion and arc-continent collision: Insights from the structural evolution of the Río San Juan metamorphic co…

2013

The Río San Juan metamorphic complex exposes a segment of a high-pressure subduction-accretionary complex built during Caribbean island arc-North America continental margin convergence. It is composed of accreted arc- and oceanic-derived metaigneous rocks, serpentinized peridotites and minor metasediments forming a structural pile. Combined detailed mapping, structural and metamorphic analysis, and geochronology show that the deformation can be divided into five main events (D1eD5). An early subduction-related D1 deformation and M1 metamorphism produced greenschist (mafic rocks of the Gaspar Hernández peridotite-tectonite), blueschist and eclogite (metamafic blocks in the Jagua Clara mélang…

GEOLOGIA DE LAS MARGENES DE LA PLACA DEL CARIBE: GENERALIDADES EN GUATEMALA, COSTA RICA, LA ESPAÑOLA Y RESULTADOS PRELIMINARES DEL ANALISIS DE UNA TR…

2011

The Caribbean Plate margins are constituted by deformed belts built up since the Cretaceous in acompressional and strike-slip stress field, which allowed overthrusting of the Caribbean crust onto the Pacific,North and South American Plates.The Caribbean borders include Jurassic-Cretaceous ophiolitic units (Great Antilles, Venezuela, Costa Rica,Guatemala, etc.), composed by mantle peridotites, gabbros, volcanic and sedimentary covers, which have beendeformed in at least two ductile penetrative phases and were often metamorphosed in the prehnite-pumpelleyite,green and blue schist, amphibolite, and in places eclogite facies. These units may present part of a subductioncomplex or are an accreti…

Structural analysis of a complex nappe sequence and late-orogenic basins from the Aegean Island of Samos, Greece

1999

The island of Samos in the Aegean Sea exposes high-pressure metamorphic rocks of the Cycladic blueschist unit which are sandwiched between the mildly blueschist-facies Kerketas nappe below and the overlying non-metamorphic Kallithea nappe. Structural and metamorphic analysis shows that deformation can generally be divided into four main stages: (1) Eocene and earliest Oligocene 0ESE‐WNW-oriented nappe stacking (D1 and D2) associated with blueschist- and transitional blueschist‐ greenschist-facies metamorphism (M1 and M2). D2 caused emplacement of the blueschist unit onto the Kerketas nappe indicating that thrusting occurred during decompression. (2) A subsequent history of Oligocene and Mio…

Los tres ejes de comportamiento del caballero literario medieval: hacia un modelo genérico

2008

La configuración del personaje protagonista de la ficción caballeresca, el caballero, está basada en un modelo genérico que delimita, administra y organiza las características que lo hacen reconocible para el público asiduo. Este modelo, a su vez,se estructura a partir de tres aspectos indisolubles a la cultura feudal y cortés de la Edad Medial: la función bélica, el amor y la cortesía, y la religión. En este artículo se analizan estos tres ejes que determinan las características del modelo de caballero y cuyadistribución marca la individualización de las realizaciones textuales.

Contribution to the flora of Asian and European countries: new national and regional vascular plant records, 2

2014

The paper presents new records for 20 vascular plant species from eight Asian and two European countries. Five taxa (Artemisia campestris, Artemisia tanacetifolia, Delphinium sajanense, Diarthron vasiculosum var. undulatum, Epilobium adenocaulon) are reported from Kazakhstan, four (Deyeuxia yanyuanensis, Poa arnoldii, Stipa gracilis, Stipa macroglossa subsp. kazachstanica) from China, three (Nepeta pamirensis, Silene bucharica, Scrophularia pamiro-alaica) from Uzbekistan, two (Epilobium nervosum, Stellaria zolotukhinii) from Mongolia, two (Oenothera deflexa, Scirpus georgianus) from Poland, one (Coronopus didymus) from Tajikistan, one (Orobanche rumseiana) from Italy, one (Stipa macroglossa…