scholarly journals Antisana volcano: A representative andesitic volcano of the eastern cordillera of Ecuador: Petrography, chemistry, tephra and glacial stratigraphy

2017 ◽  
Vol 73 ◽  
pp. 50-64 ◽  
Author(s):  
Minard L. Hall ◽  
Patricia A. Mothes ◽  
Pablo Samaniego ◽  
Annemarie Militzer ◽  
Bernardo Beate ◽  
...  
Keyword(s):  
Eastern Cordillera ◽  
Andesitic Volcano

scholarly journals The Upper Oligocene San Rafael intrusive complex (Eastern Cordillera, southeast Peru), host of the largest-known high-grade tin deposit

Lithos ◽  
2021 ◽  
pp. 106409
Author(s):  
Matthieu Harlaux ◽  
Kalin Kouzmanov ◽  
Stefano Gialli ◽  
Alan H. Clark ◽  
Oscar Laurent ◽  
...  
Keyword(s):  
High Grade ◽  
Intrusive Complex ◽  
Eastern Cordillera ◽  
Upper Oligocene ◽  
San Rafael ◽  
Tin Deposit

scholarly journals Coal petrology analysis and implications in depositional environments from upper Cretaceous to Miocene: a study case in the Eastern Cordillera of Colombia

2021 ◽  
Author(s):  
Clara Guatame ◽  
Marco Rincón
Keyword(s):  
Late Cretaceous ◽  
Foreland Basin ◽  
Late Eocene ◽  
Depositional Environments ◽  
Estuarine System ◽  
Eastern Cordillera ◽  
Stratigraphic Position ◽  
San Fernando ◽  
Coal Facies ◽  
Oil Sector

AbstractThe Piedemonte Llanero Basin is located on the eastern side of the Eastern Cordillera of the Colombian Andes. It has been the subject of numerous geological studies carried out for the oil sector, mainly. This study presents the coal-petrographical features of 15 coal seams of four geological formations from Late Cretaceous to Middle Miocene (Chipaque formation, Palmichal group, Arcillas del Limbo formation, and San Fernando formation). Analysis of 33 samples indicates enrichment in vitrinite, while liptinite and inertinite concentrations vary according to the stratigraphic position. Reflectance indicates that the coal range gradually decreases from highly volatile bituminous C (Chipaque formation) to subbituminous C (San Fernando formation). The microlithotypes with the highest concentrations are clarite and vitrinertoliptite. Maceral composition and coal facies indicate changes in the depositional conditions of the sequence. The precursor peat from Late Cretaceous to Late Paleocene accumulated under limnic conditions followed by telmatic in Late Eocene–Early Miocene. The coal facies indices show wet conditions in forest swamps with variations in the flooding surface, influxes of brackish water and good tissue preservation. The tectonic conditions along the Piedemonte Llanero basin is evident, from post-rift to foreland basin, evidenced by oxic and anoxic periods reflected in the maceral composition and its morphology. The coal environment corresponds to an estuarine system started in the Chipaque formation evolving to the lacustrine conditions in the San Fernando formation.

The influence of backstop geometry in the structural style of the Eastern Cordillera of Colombia: A sandbox modeling approach 

2021 ◽  
Author(s):  
Camilo Andrés Conde Carvajal ◽  
Cristhian Bolívar Riascos Rodríguez ◽  
Michael Andres Avila Paez ◽  
Andreas Kammer
Keyword(s):  
Kink Band ◽  
Ductile Deformation ◽  
High Plains ◽  
Angle Of Internal Friction ◽  
Eastern Cordillera ◽  
Surface Uplift ◽  
Structural Style ◽  
Mountain System ◽  
Mountain Front ◽  
Structural Relief

<p>Among the foreland belts of the Andean mountain system, the Eastern Cordillera of Colombia (EC) represents a unique example of an isolated, bi-vergent mountain belt. In contrast, to block tectonics of broken foreland basins, it displays a ductile deformation style which involves two mountain fronts with a structural relief of the order of 10 km. Internal parts of the EC have been shortened by buckling at high and a homogeneously strained basement at deeper structural levels. These deformation patterns likely attest to conditions of a thermally weakened backarc setting. Two opposed scenarios have been postulated for its surface uplift and consequent exhumation: 1) an E-migrating deformation front and the formation of progressively forward breaking faults; and 2) the pop-up of a weak crustal welt enclosed by strong foreland blocks. In this latter setting, a synchronous early formation of marginal mountain fronts and a late-stage surface uplift of a central domain may be anticipated. These two constellations compare, in terms of a contrasting model setup, to a foreland migrating orogenic wedge or a relatively stable, doubly vergent wedge formed above a structural discontinuity or rheologic boundaries that acted as sites for the nucleation of the marginal faults.</p><p>In this contribution, we opt to examine the “boundary” conditions for the development of a doubly vergent wedge formed at the tip line of a rigid tapering backstop, that simulates a rigid foreland block. With respect to the shape of this backstop, we examine the effects of tip angles less than the angle of internal friction (<30°) and find, that at a low tip angle of 10° the pop-up evolves above a forward-breaking principal kink-band with the synchronous formation of a sequence of conjugate back-kinks that cut into the sand pack, as it is pushed toward the backstop. At a moderate tip angle of 20<sup>o </sup>the forward-breaking kink-band is slightly steeper than the backstop and gives rise to a frontal fold with an overturned limb. This latter geometrical configuration loosely compares to the structural relations of a structural section through the high plains of Bogotá, where the eastern mountain front defines a strongly deformed antiform, that is juxtaposed against an undeformed margin of the adjacent Guyana shield.</p>

Non-explosive magma–water interaction in a continental setting: Miocene examples from the Eastern Cordillera (central Andes; NW Argentina)

2008 ◽  
Vol 71 (5) ◽  
pp. 509-532 ◽  
Author(s):  
Luigina Vezzoli ◽  
Massimo Matteini ◽  
Natalia Hauser ◽  
Ricardo Omarini ◽  
Roberto Mazzuoli ◽  
...  
Keyword(s):  
Central Andes ◽  
Cordillera Central ◽  
Eastern Cordillera ◽  
Water Interaction

scholarly journals First record of Sphaeronycteris toxophyllum Peters, 1882 (Chiroptera: Phyllostomidae) for the Department of Boyacá, Eastern Cordillera of Colombia

Check List ◽  
2014 ◽  
Vol 10 (3) ◽  
pp. 697-699
Author(s):  
Arley Omar Gallardo ◽  
Lesly Rocio Peña ◽  
Orlando Armesto ◽  
Jonathan Sequeda
Keyword(s):  
First Record ◽  
Eastern Cordillera
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