Results 11 to 20 of about 151,062 (248)

Grenvillian massif-type anorthosites in the Sierras Pampeanas [PDF]

Journal of the Geological Society, 2005
We report the discovery of massif-type anorthosites in the Andean basement of the Western Sierras Pampeanas of Argentina. U–Pb zircon dating (by sensitive high-resolution ion microprobe) of a cogenetic gabbronorite dyke yields ages of 1070 ± 41 Ma for igneous emplacement and 431 ± 40 Ma for metamorphism.
Casquet, Cesar, Pankhurst, Robert J, Rapela, Carlos W, Galindo, Carmen, Dahlquist, Juan A., Baldo, Edgardo, Saavedra, J, Gonzalez-Casado, Jose M, Fanning, Christopher   +8 more
openaire   +8 more sources

Localization of Deformation in a Non‐Collisional Subduction Orogen: The Roles of Dip Geometry and Plate Strength on the Evolution of the Broken Andean Foreland, Sierras Pampeanas, Argentina

Tectonics, Volume 42, Issue 8, August 2023., 2023
The southern Central Andes (SCA, 27°–40°S) exhibit a complex deformation pattern that is influenced by multiple factors, including the present‐day dip angle of the subducting oceanic Nazca plate and the influence of inherited heterogeneities in the ...
Michaël Pons, C. R. Piceda, S. Sobolev, M. Scheck‐Wenderoth, M. Strecker   +4 more
semanticscholar   +2 more sources

Are Volatiles From Subducted Ridges on the Pampean Flat Slab Fracking the Crust? Evidence From an Enhanced Seismicity Catalog

Geochemistry, Geophysics, Geosystems, Volume 24, Issue 10, October 2023., 2023
Abstract Seamounts and ridges are often invoked to explain subduction‐related phenomena such as flat slab generation, but the extent of their involvement remains controversial. An analysis of seismicity in the region of the Pampean flat slab through an application of an automated catalog generation algorithm resulted in 35,924 well constrained local ...
A. Maharaj, S. Roecker, P. Alvarado, S. Trad, S. Beck, D. Comte   +5 more
wiley   +1 more source

Transient Injection of Flow: How Torn and Bent Slabs Induce Unusual Mantle Circulation Patterns Near a Flat Slab

Geochemistry, Geophysics, Geosystems, Volume 24, Issue 10, October 2023., 2023
Abstract Torn and bent slabs are usually associated with flat‐slab subduction where the descending plate develops a horizontal geometry beneath the overlying continent. How such slab dynamics modify the surrounding mantle flow and the overriding plate remains enigmatic.
Xiaowen Liu, Russell Pysklywec
wiley   +1 more source

Timing of the Transition From Sevier‐ to Laramide‐Style Tectonism in Southwestern Montana Based on the Provenance of the Frontier Formation, North American Cordillera

Tectonics, Volume 42, Issue 8, August 2023., 2023
Abstract The Upper Cretaceous Frontier Formation in southwestern Montana is coeval with the transition from Sevier‐ to Laramide‐style tectonism in the Idaho‐Montana sector of the North American Cordillera. To better constrain the timing of initial exhumation above the Laramide‐style Blacktail‐Snowcrest arch, we use biostratigraphic data, sandstone ...
E. S. Finzel, J. A. Rosenblume, D. M. Pearson, Pierre A. Zippi   +3 more
wiley   +1 more source

Stepwise Widening of the Central Andes—The Role of the Lower Crust

Geophysical Research Letters, Volume 50, Issue 12, 28 June 2023., 2023
Abstract The outward growth of many orogens occurs through pulsed migration of the strain front. During Cenozoic shortening of the central Andes, the strain front abruptly migrated ∼400 km eastward across the Altiplano, isolating the plateau interior from major deformation.
Huilin Wang, Claire A. Currie
wiley   +1 more source

Circular Natural Geoforms, Sierras Pampeanas, Argentina

Open Journal of Geology, 2017
We describe two circular morphological features representing depressed areas. This preliminary work is based on visual interpretations from Landsat ETM satellite images and SRTM Radar scans. The two geoforms are located at the north of the Sierras Pampeanas in Argentina. The La Cienaga circular indentation is 15 km in diameter and Las Cejas is 34 km in
Gutierrez, Adolfo Antonio, Mon, Ricardo, Cisterna, Clara Eugenia   +2 more
openaire   +3 more sources

Early Cambrian U-Pb zircon age and Hf-isotope data from the Guasayán pluton, Sierras Pampeanas, Argentina: implications for the northwestern boundary of the Pampean arc [PDF]

, 2016
An Early Cambrian pluton, known as the Guasayán pluton, has been identified in the central area of Sierra de Guasayán, northwestern Argentina. A U?Pb zircon Concordia age of 533 ± 4 Ma was obtained by LA-MC-ICP-MS and represents the first report of ...
Alasino, Pablo Horacio, Baldo, Edgardo Gaspar Agustín, Basei, Miguel A. S., da Costa Campos Neto, Mario, Dahlquist, Juan Andrés, Rapela, Carlos Washington, Uran, Gimena Mariel, Verdecchia, Sebastián Osvaldo, Zandomeni, Priscila Soledad   +8 more
core   +2 more sources

Protracted Thermal Evolution of a Migmatitic Terrane as Revealed by Multiple Geochronometers From the Retro‐Arc of the Early Paleozoic Famatinian Orogen in NW Argentina

Tectonics, Volume 42, Issue 3, March 2023., 2023
Abstract U‐Pb dates of zircon, monazite, and titanite combined with trace element composition, allows characterization of the thermal evolution of the migmatitic Agua del Sapo complex. This complex comprises Al‐rich and Ca‐rich metasedimentary rocks with a detrital zircon maximum depositional age of 550 Ma.
Pablo Farias, Roberto F. Weinberg, Alfonso Sola, Melanie Finch   +3 more
wiley   +1 more source

The Difunta Correa metasedimentary sequence (NW Argentina): relict of a Neoproterozoic platform? — elemental and Sr-Nd isotope evidence

Revista Mexicana de Ciencias Geológicas, 2018
The Sierra de Pie de Palo (Western Sierras Pampeanas, Argentina) in the Andean foreland is mainly formed by a Mesoproterozoic basement and an Ediacaran metasedimentary cover referred to as the Difunta Correa metasedimentary sequence.
Carlos Ramacciotti, César Casquet, Edgardo Baldo, Carmen Galindo   +3 more
doaj   +1 more source