Superposition of tectono-thermal episodes in the southern Cantabrian Zone (foreland thrust and fold belt of the Iberian Variscides, NW Spain)

2005 ◽  
Vol 176 (6) ◽  
pp. 487-497 ◽  
Author(s):  
Jesus Aller ◽  
María Luz Valín ◽  
Susana García-López ◽  
Covadonga Brime ◽  
Fernando Bastida
Keyword(s):  
First Episode ◽  
Fold Belt ◽  
Illite Crystallinity ◽  
Nw Spain ◽  
Precambrian Rocks ◽  
Combined Use ◽  
Extensional Tectonic ◽  
Thin Skin ◽  
Conodont Colour Alteration Index ◽  
Variscan Metamorphism

Abstract The combined use of the illite “crystallinity” Kübler index (KI) and the conodont colour alteration index (CAI) has revealed the existence of three thermal episodes in an area affected by thin-skin tectonics, close to the internal zones of the Variscan orogen in NW Spain. In the southernmost part of the study area, the first episode gave rise to a regional syntectonic Variscan metamorphism. The associated deformation involves the development of a slaty cleavage, which is mainly recognized in Precambrian rocks. Towards the foreland, the syntectonic metamorphism disappears and only an incipient burial metamorphism, giving rise to anchizonal conditions in the basal part of the thrust units, is observed. Another metamorphic episode occurred close to the Carboniferous-Permian boundary in an extensional tectonic regime. This metamorphism is restricted to the northern part of the study area, where it reached anchizonal or epizonal conditions. It is associated with a subhorizontal or moderately north-dipping cleavage and can be considered as a late-Variscan episode. The last thermal episode occurred during the Permian. It was produced by heat flow due to hydrothermal fluids, whose migration was favoured by faults. The effects of this episode are irregularly distributed, and they are apparent in the unconformable Stephanian rocks in which anchizonal or epizonal conditions were reached. It is interpreted as a post-Variscan episode.

Variscan metamorphism and K-Ar dates in the Variscan fold belt of S Brittany and NW Spain

1979 ◽  
Vol 136 (1) ◽  
pp. 89-103 ◽  
Author(s):  
Alison C. Ries
Keyword(s):  
Fold Belt ◽  
Nw Spain ◽  
Variscan Metamorphism

Transition from diagenesis to metamorphism in a calcareous tectonic unit of the Iberian Variscan belt (central massif of the Picos de Europa, NW Spain)

2004 ◽  
Vol 141 (5) ◽  
pp. 617-628 ◽  
Author(s):  
FERNANDO BASTIDA ◽  
SILVIA BLANCO-FERRERA ◽  
SUSANA GARCÍA-LÓPEZ ◽  
JAVIER SANZ-LÓPEZ ◽  
M. LUZ VALÍN
Keyword(s):  
First Episode ◽  
Thermal Anomalies ◽  
Tectonic Regime ◽  
The North ◽  
Kübler Index ◽  
Hydrothermal Processes ◽  
Extensional Tectonic ◽  
Conodont Colour Alteration Index ◽  
Present Pattern ◽  
Carboniferous Limestone

Transition from diagenesis to metamorphism has been characterized in the central part of the Picos de Europa unit (Cantabrian Zone) by conodont colour alteration index (CAI), complemented with Kübler index (KI) data. This unit essentially comprises Carboniferous limestone. The study leads us to deduce two successive tectonothermal events. The first event generated a pattern with palaeotemperatures increasing towards the Pisuerga–Carrión unit, located south of the Picos de Europa unit. The present pattern is the result of an original dip to the north of the isothermal surfaces and the subsequent rising of the Picos de Europa unit along the frontal ramp of a deep Alpine thrust. This episode is interpreted as related to an extensional tectonic regime that occurred close to the Carboniferous–Permian boundary. The second event, which gave rise to thermal anomalies in the pattern of the first episode, was the result of hydrothermal processes in which fluid movement was facilitated by a dense network of fractures in the area close to the eastern section of the studied region. These processes gave rise to numerous mineralizations and have been related to a Permian extensional tectonic regime.

Clay mineral evidence for low-grade Caledonian and Variscan metamorphism in south-western Dyfed, south Wales

1980 ◽  
Vol 43 (331) ◽  
pp. 857-863 ◽  
Author(s):  
D. Robinson ◽  
R. A. Nicholls ◽  
L. J. Thomas
Keyword(s):  
Lower Cambrian ◽  
Volatile Matter ◽  
Low Grade ◽  
X Ray Diffraction ◽  
Illite Crystallinity ◽  
X Ray ◽  
South Wales ◽  
Mineral Assemblages ◽  
Variscan Metamorphism ◽  
Pelitic Rocks

SummaryIllite crystallinity determinations on Palaeozoic pelitic rocks, whose stratigraphic range runs from Lower Cambrian to Westphalian, indicate that anchimetamorphism has affected both the Lower and Upper Palaeozoic sequences. Two metamorphic episodes are in evidence, with the earlier, Caledonian, being of slightly higher grade. The higher anchizone crystallinity values are recorded from the Fishguard area in which mineral assemblages of the prehnite-pumpellyite facies have recently been recognized in basic igneous rocks. The later metamorphic episode has affected rocks to the south of the Variscan front. Here crystallinity values are low anchizone but some straddle the boundary with the diagenetic state. The Pembroke coalfield lies in this southern area and has coals largely of anthracite rank with volatile matter contents of between 10.1 and 5% Grade of metamorphism as indicated by crystallinity and by coal rank data from the Pembroke coalfield shows anomalous results to that described from the main South Wales coalfield. A neo-formed 2M illite from the Variscan spaced cleavage is described with analytical and X-ray diffraction data.

scholarly journals The Effect of Ranitidine on Olanzapine-Induced Weight Gain

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Fatemeh Ranjbar ◽  
Alireza Ghanepour ◽  
Homayoun Sadeghi-Bazargani ◽  
Mahbob Asadlo ◽  
Amineh Alizadeh
Keyword(s):  
Weight Gain ◽  
Family History ◽  
Positive Family History ◽  
First Episode ◽  
Long Run ◽  
Combined Use ◽  
History Of ◽  
History Of Obesity ◽  
Baseline Bmi ◽  
First Time

Induced weight gain is a disturbing side effect of Olanzapine that affects the quality of life in psychotic patients. The aim of this study was to assess the efficacy of Ranitidine in attenuating or preventing Olanzapine-induced weight gain. A parallel 2-arm clinical trial was done on 52 patients with schizophrenia, schizoaffective and schizophreniform disorders who received Olanzapine for the first time. All these were first-episode admitted patients. They were randomly allocated to receive either Ranitidine or placebo. The trend of body mass index (BMI) was compared between groups over 16-week course of treatment. Mean weight was 62.3 (SD: 9.6) kg at baseline. Thirty-three subjects (63.5%) had positive family history of obesity. The average BMI increment was 1.1 for Ranitidine group and 2.4 for the placebo group. The multivariate analysis showed this effect to be independent of sex, family history of obesity, and baseline BMI value. The longitudinal modeling after controlling for baseline values failed to show the whole trend slope to be different. Although the slight change in trend’s slope puts forward a hypothesis that combined use of Ranitidine and Olanzapine may attenuate the weight gain long run, this needs to be retested in future larger scale long-term studies. This trial is registered with IRCT.ir201009112181N5.

The metamorphic history of the concealed Caledonides of eastern England and their foreland

1993 ◽  
Vol 130 (5) ◽  
pp. 613-620 ◽  
Author(s):  
R. J. Merriman ◽  
T. C. Pharaoh ◽  
N. H. Woodcock ◽  
P. Daly
Keyword(s):  
Lower Devonian ◽  
Regional Metamorphism ◽  
White Mica ◽  
Fold Belt ◽  
Illite Crystallinity ◽  
Metamorphic History ◽  
Diagenetic Alteration ◽  
History Of ◽  
Volcaniclastic Rocks ◽  
Early Palaeozoic

AbstractWhite mica (illite) crystallinity data, derived mostly from borehole samples, have been used to generate a contoured metamorphic map of the concealed Caledonide fold belt of eastern England and the foreland formed by the Midlands Microcraton. The northern subcrop of the fold belt is characterized by epizonal phyllites and quartzites of possible Cambrian age, whereas anchizonal grades characterize Silurian to Lower Devonian strata of the Anglian Basin in the southern subcrop of the fold belt. Regional metamorphism in the Anglian Basin resulted from deep burial and Acadian deformation beneath a possible overburden of 7 km, assuming a metamorphic field gradient of 36 °C km-1. Late Proterozoic volcaniclastic rocks forming the basement of the microcraton show anchizonal to epizonal grades that probably developed during late Avalonian metamorphism. Cambrian to Tremadoc strata, showing late diagenetic alteration, rest on the basement with varying degrees of metamorphic discordance. During early Palaeozoic times, much of the microcraton was a region of slow subsidence with overburden thicknesses of 3.3–5.5 km. However, concealed Tremadoc strata in the northeast of the microcraton reach anchizonal grades and may have been buried to depths of 7 km beneath an overburden of uncertain age.

Thrust systems of the Southwest Pyrenees and their control over basin subsidence

1990 ◽  
Vol 127 (5) ◽  
pp. 383-392 ◽  
Author(s):  
J. P. Turner ◽  
P. L. Hancock
Keyword(s):  
The South ◽  
Mountain Building ◽  
The West ◽  
Tectonic Regime ◽  
Basin Subsidence ◽  
Extensional Tectonic ◽  
Thin Skin ◽  
Thrust System ◽  
Thick Skin ◽  
Local Uplift

AbstractThere are two thrust systems in the Southwest Pyrenees: a NW-SE trending, thin-skin system exposed in the post-Triassic cover and a larger, thick-skin system of NE-SW thrusts in the Palaeozoic basement. The ‘cover’ thrust system propagated and migrated both southward and westward in response to the non-orthogonal collision of Iberia with Europe during Palaeogene mountain building. The ‘basement’ thrust system is interpreted to be a longer-lived structure, initiated during the extensional tectonic regime in mid Cretaceous time, and inverted during the main episode of Pyrenean collision. A model in which interaction of the two thrust systems controlled the timing and magnitude of thrust-induced, flexural subsidence is presented. The development of the basement thrust system caused regional subsidence along the South Pyrenean foreland margin that was subsequently halted by local uplift associated with the west-migratingcover thrust system.

Wound Care of Pretibial Thin-skin Lacerations With the Combined Use of Sterile Adhesive Strips and Sutures

2015 ◽  
Vol 49 (3) ◽  
pp. 345-346
Author(s):  
Lorenzo Andreana ◽  
Graziella Isgrò ◽  
Victoria Metaxa
Keyword(s):  
Wound Care ◽  
Combined Use ◽  
Thin Skin

scholarly journals Conodont alteration and tectonothermal evolution of a diagenetic unit in the Iberian Variscan belt (Ponga-Cuera unit, NW Spain)

2010 ◽  
Vol 148 (1) ◽  
pp. 35-49 ◽  
Author(s):  
SILVIA BLANCO-FERRERA ◽  
JAVIER SANZ-LÓPEZ ◽  
SUSANA GARCÍA-LÓPEZ ◽  
FERNANDO BASTIDA ◽  
M. LUZ VALÍN
Keyword(s):  
Geothermal Gradient ◽  
Ore Deposits ◽  
Nw Spain ◽  
Complementary Method ◽  
Kübler Index ◽  
Conodont Colour Alteration Index ◽  
External Part ◽  
Great Uniformity ◽  
Local Anomalies ◽  
Dissolution And Precipitation

AbstractTectonothermal analysis of a mainly carbonate unit located in the external part of the Variscan orogen in NW Spain is dealt with using the conodont colour alteration index (CAI) and the study of textures of these microfossils. The Kübler index of the illite (KI) is used as a complementary method. The area is characterized by a great uniformity in the CAI values, which in most cases are <2, indicating diagenetic conditions. In spite of the low CAI values, textures show great variety and were mainly originated by diagenetic processes of apatite dissolution and precipitation. The conodonts underwent a long period of heating (probably from the Pennsylvanian to the Cenozoic) to low temperatures (<100°C) to reach the low CAI values measured. Assuming a normal geothermal gradient, these temperatures required an overburden <3 km that in part was due to burial and in part to tectonic superimposition. Minor local anomalies in the CAI values and some textural alterations, related to dissolution and precipitation of authigenic minerals, could be due to epithermal activity that gave rise to various ore deposits in the studied area mainly during Permian times.

Sign in / Sign up

Export Citation Format

Share Document