The Late Paleogene to Neogene Volcanic Arc in the Southern Central Andes (28°–37° S)

2018 ◽  
pp. 503-536 ◽  
Author(s):  
Vanesa D. Litvak ◽  
Stella Poma ◽  
Rosemary E. Jones ◽  
Lucía Fernández Paz ◽  
Sofía B. Iannelli ◽  
...  
Keyword(s):  
Central Andes ◽  
Volcanic Arc ◽  
Southern Central

scholarly journals Supplemental Material: Detrital zircon record of Phanerozoic magmatism in the southern Central Andes

2021 ◽  
Author(s):  
T.N. Capaldi ◽  
et al.
Keyword(s):  
Detrital Zircon ◽  
Central Andes ◽  
Slab Geometry ◽  
Volcanic Arc ◽  
Data Table ◽  
Data Compilation ◽  
Southern Central

Text S1: Analytical metadata. Table S2: Pleistocene–Holocene Andean volcanos and slab geometry. Table S3: Pleistocene–Holocene volcanic arc width and melt depth calculations. Table S4: Bedrock geochronology and location compilation. Table S5: Mesozoic–Cenozoic slab angle calculations. Table S6: Detrital zircon U-Th-Pb data. Table S7: Detrital zircon Hf data. Table S8: Detrital zircon U-Th-Pb data compilation. Table S9: Zircon Lu-Hf data compilation.

scholarly journals Supplemental Material: Detrital zircon record of Phanerozoic magmatism in the southern Central Andes

2021 ◽  
Author(s):  
T.N. Capaldi ◽  
et al.
Keyword(s):  
Detrital Zircon ◽  
Central Andes ◽  
Slab Geometry ◽  
Volcanic Arc ◽  
Data Table ◽  
Data Compilation ◽  
Southern Central

Text S1: Analytical metadata. Table S2: Pleistocene–Holocene Andean volcanos and slab geometry. Table S3: Pleistocene–Holocene volcanic arc width and melt depth calculations. Table S4: Bedrock geochronology and location compilation. Table S5: Mesozoic–Cenozoic slab angle calculations. Table S6: Detrital zircon U-Th-Pb data. Table S7: Detrital zircon Hf data. Table S8: Detrital zircon U-Th-Pb data compilation. Table S9: Zircon Lu-Hf data compilation.

scholarly journals Southern Central Andes Neogene magmatism over the Pampean Flat Slab: implications on crustal and slab melts contribution to magma generation in Precordillera, Western Argentina

2017 ◽  
Vol 44 (3) ◽  
pp. 249 ◽  
Author(s):  
Stella Poma ◽  
Adriana Ramos ◽  
Vanesa D. Litvak ◽  
Sonia Quenardelle ◽  
Emma B. Maisonnave ◽  
...  
Keyword(s):  
Volcanic Rocks ◽  
Central Andes ◽  
Progressive Increase ◽  
Geochemical Data ◽  
Transitional Region ◽  
Continuous Increase ◽  
Volcanic Arc ◽  
Age Variations ◽  
Southern Central ◽  
Back Arc

A Miocene to Pliocene (13 to 4.6 Ma) mostly pyroclastic sequence is exposed along the Iglesia Valley, to the east of the former main volcanic arc. This area is a transitional region between Cordillera Frontal and Precordillera, over the f lat slab segment of the Southern Central Andes, at 29º30’ S to 30º00’ S. New radiometric ages, geochemical data, petrography and field relationships are evaluated to establish differences and similarities between Miocene arcrelated sequences across the main arc and its expansion towards a back arc position, in western Precordillera. Analyzed rocks have a magmatic arc signature partially like the former main volcanic arc to the west. The Iglesia Valley rocks are LREE-enriched (La/Sm: 3.7-6.5) with respect to HREE (Sm/Yb: 2.2-6.0) and define patterns with a pronounced slope. Sm/Yb ratios generally increase with time, as pressures increase, with retention of HREE in residual mineralogy, particularly garnet at Sm/Yb>4. Volcanic activity in Cordillera Frontal and the volcanic-volcaniclastic expression in Precordillera show a continuous increase in the La/Yb ratio with decreasing age. Variations in the residual mineralphase equilibrating with magmas would be related to the progressive increase in crustal thickness due to the tectonic compressive regime resulting from shallow subduction since Middle Miocene. The data presented suggest that the arc magmatic activity during the Miocene was expanded notably to the East in relation to the location of the main arc at Valle del Cura, in Cordillera Frontal. The extensive amplitude of the volcanic arc activity is indicative of the slab gradual f lattening. Particularly, the mantle-derived magmas from Lomas del Campanario Formation (Western Precordillera) are enriched by subduction related f luids but also by crustal components. It is interpreted that the cause of the geochemical differences between the back arc position rocks and the main arc lay in the heterogeneous composition of the underlying continental crust involved in both locations. Presence of volcanic rocks with adakitic geochemical affinity probably ref lect astenospheric-derived melts that interacted through a heterogeneous and thickened crust toward the surface.

RETROARC BASIN REORGANIZATION AND DIACHRONOUS ARIDIFICATION DURING PALEOGENE UPLIFT OF THE SOUTHERN CENTRAL ANDES

2016 ◽  
Author(s):  
Julie C. Fosdick ◽  
◽  
Barbara Carrapa ◽  
Barbara Carrapa ◽  
Ellen J. Reat ◽  
...  
Keyword(s):  
Central Andes ◽  
Southern Central

A COUPLED LACUSTRINE AND ALLUVIAL FAN RECORD FOR THE HOLOCENE OF THE ARID SOUTHERN CENTRAL ANDES

2017 ◽  
Author(s):  
José Luis Antinao ◽  
◽  
Rachel Tiner ◽  
Rachel Tiner ◽  
Rachel Tiner ◽  
...  
Keyword(s):  
Central Andes ◽  
Alluvial Fan ◽  
The Holocene ◽  
Southern Central

Geochemistry and isotope systematics of small- to medium-volume Neogene–Quaternary ignimbrites in the southern central Andes: evidence for derivation from andesitic magma sources

2001 ◽  
Vol 171 (3-4) ◽  
pp. 213-237 ◽  
Author(s):  
Wolfgang Siebel ◽  
Wolfgang B.W. Schnurr ◽  
Knut Hahne ◽  
Bernhard Kraemer ◽  
Robert B. Trumbull ◽  
...  
Keyword(s):  
Central Andes ◽  
Andesitic Magma ◽  
Magma Sources ◽  
Southern Central ◽  
Isotope Systematics

scholarly journals Early last glacial maximum in the southern Central Andes reveals northward shift of the westerlies at ~39 ka

2011 ◽  
Vol 7 (1) ◽  
pp. 41-46 ◽  
Author(s):  
R. Zech ◽  
J. Zech ◽  
Ch. Kull ◽  
P. W. Kubik ◽  
H. Veit
Keyword(s):  
Last Glacial Maximum ◽  
Central Andes ◽  
Glacial Maximum ◽  
Atmospheric Co2 ◽  
Dissolved Carbon ◽  
Last Glacial ◽  
Exposure Dating ◽  
Latitudinal Position ◽  
Southern Central ◽  
Southern Westerlies

Abstract. The latitudinal position of the southern westerlies has been suggested to be a key parameter for the climate on Earth. According to the general notion, the southern westerlies were shifted equatorward during the global Last Glacial Maximum (LGM: ~24–18 ka), resulting in reduced deep ocean ventilation, accumulation of old dissolved carbon, and low atmospheric CO2 concentrations. In order to test this notion, we applied surface exposure dating on moraines in the southern Central Andes, where glacial mass balances are particularly sensitive to changes in precipitation, i.e. to the latitudinal position of the westerlies. Our results provide robust evidence that the maximum glaciation occurred already at ~39 ka, significantly predating the global LGM. This questions the role of the westerlies for atmospheric CO2, and it highlights our limited understanding of the forcings of atmospheric circulation.

Average Pleistocene Climatic Patterns in the Southern Central Andes: Controls on Mountain Glaciation and Paleoclimate Implications

2002 ◽  
Vol 110 (2) ◽  
pp. 211-226 ◽  
Author(s):  
Kirk Haselton ◽  
George Hilley ◽  
Manfred R. Strecker
Keyword(s):  
Central Andes ◽  
Southern Central ◽  
Mountain Glaciation

scholarly journals Timing and extent of late pleistocene glaciation in the arid Central Andes of Argentina and Chile (22°-41°S)

2017 ◽  
Vol 43 (2) ◽  
pp. 697 ◽  
Author(s):  
J. Zech ◽  
C. Terrizzano ◽  
E. García-Morabito ◽  
H. Veit ◽  
R. Zech
Keyword(s):  
Southern Oscillation ◽  
Co2 Concentration ◽  
Late Glacial ◽  
Central Andes ◽  
The North ◽  
Eastern Equatorial Pacific ◽  
Southern Central ◽  
Study Sites ◽  
Increasing Temperature ◽  
Exposure Ages

The arid Central Andes are a key site to study changes in intensity and movement of the three main atmospheric circulation systems over South America: the South American Summer Monsoon (SASM), the Westerlies and the El Niño Southern Oscillation (ENSO). In this semi-arid to arid region glaciers are particularly sensitive to precipitation changes and thus the timing of past glaciation is strongly linked to changes in moisture supply. Surface exposure ages from study sites between 41° and 22°S suggest that glaciers advanced: i) prior to the global Last Glacial Maximum (gLGM) at ~40 ka in the mid (26°- 30°S) and southern Central Andes (35°-41°S), ii) in phase with the gLGM in the northern and southern Central Andes and iii) during the late glacial in the northern Central Andes. Deglaciation started synchronous with the global rise in atmospheric CO2 concentration and increasing temperature starting at ~18 ka. The pre-gLGM glacial advances likely document enhanced precipitation related to the Southern Westerlies, which shifted further to the North at that time than previosuly assumed. During the gLGM glacial advances were favored by decreased temperatures in combination with increased humidity due to a southward shifted Intertropical Convergence Zone (ITCZ) and SASM. During the late-glacial a substantial increase in moisture can be explained by enhanced upper tropospheric easterlies as response to an intensified SASM and sustained La Niña-like conditions over the eastern equatorial Pacific that lead to glacial advances in the northern Central Andes and the lake level highstand Tauca (18-14 ka) on the Altiplano. In the southernmost Central Andes at 39º-41°S, further north at 31°S and in the northernmost Central Andes at 22°S glacial remnants even point to precipitation driven glaciations older than ~115 ka and 260 ka.

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