Geology of Chile - Wikipedia
convergent margin between the Nazca and South American plates. (Fig. during the Holocene characterize the recent tectonics of the LOFS. (Cembrano et al. . seismicity analyzed in the Aysén Fjord study, exclusively related to the LOFS. Figure 2: Relation between different values to describe ground motions due to an . Directions of plate motion between the South American, Nazca and area around Aysén fjord with indication of the different tectonic plates and subduction. The geology of Chile is a characterized by processes linked to subduction such as volcanism, Since Chile is on an active continental margin, it has a large number of At Taitao, the Chile Triple Junction and the Nazca Plate subduct the South Below 42 degrees south, the Andes split into a fjord landscape and the.
The place where one plate subducts beneath another is called a trench. The place where new ocean crust is formed is called a ridge. It can be seen as the recycling of the ocean crust — new ocean crust is formed at the mid-oceanic ridges and is consumed destroyed at the subduction zones trenches.
Sea floor spreading This process of new ocean crust forming at the ridges and moving towards the trenches where it is consumed is the essence of sea floor spreading.
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It is because of this reason that the ocean crust is always younger than the continental crust. In general, the rate at which ocean plates move is determined by the rate at which new ocean crust is formed at the ridges. Mid-oceanic ridges are generally located far away from the trenches. This allows the ocean crust to age a bit before it is consumed at the trenches. However, in the case of Chile, the Chile ridge is located close to the Trench.
That is not the only complex tectonic feature.
Geology of Chile
The southern Chile triple junction is a magnificent showpiece of a ridge-trench collision. The Chile triple junction region is one of only two presently active examples of a ridge-trench collision. The other being the west coast of North America; the ridge-trench collision is very prominent along the California continental margin. The Chile Ridge collides with the Chile Trench at a highly oblique angle.
As the newly produced ocean crust moves parallel to the South American coast, the age of crust becomes progressively older from south to north along the eastern edge of Nazca Plate.
There have been 3 instances when the Ridge had collided with the Chile Trench. AfricaAntarcticaAustralia and India were near Chile. When Pangaea began to split apart during the Jurassic period, South America and the adjacent land masses formed Gondwana.
Floral affinities among these now-distant landmasses date from the Gondwanaland period. South America separated from Antarctica and Australia 27 million years ago with the development of the Drake Passage.
The formation of the Andes began during the Jurassic. During the Cretaceousthe Andes began to assume their present form by the uplifting, faulting and folding of sedimentary and metamorphic rocks of ancient cratons.
Tectonic forces along the subduction zone along the west coast of South America continue to their orogenesisresulting in earthquakes and volcanic eruptions to this day.
Cenozoic Era[ edit ] The Altiplano plateau was formed during the Tertiarywith several mechanisms proposed; all attempt to explain why the topography of the Andes incorporates a large area of low relief at high altitude high plateau: Existence of weaknesses in the Earth's crust prior to tectonic shortening.
Such weaknesses would cause the partition of tectonic deformation and uplift into eastern and western cordillera, leaving the necessary space for the formation of the Altiplano basin. Magmatic processes rooted in the asthenosphere might have contributed to uplift the plateau.
Chile: where three tectonic plate boundaries meet - The Hindu
Climate controlled the spatial distribution of erosion and sediment deposition, creating the lubrication along the Nazca Plate subduction and hence influencing the transmission of tectonic forces into South America.
Climate also determined the formation of internal drainage endorheism and sediment trapping within the Andes, potentially blocking tectonic deformation in the area between the two cordilleras.
These include ice fieldsfjordsglacial lakes and u-shaped valleys. South of Chacao Channel, Chile's coast is split by fjords, islands and channels; these glaciers created moraines at the edges of the Patagonian lakes, changing their outlets to the Pacific and shifting the continental divide.
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