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Tectonics of the Northern Andes: Geochronology, Geochemistry, Isotopic Tracing, and Thermochronology

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Special Issue Editors

Dr. Richard Spikings

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Guest Editor

Department of Earth Sciences, Université de Genève, 1205 Geneva, Switzerland
Interests: thermochronology; ⁴⁰Ar/³⁹Ar method; U–Pb method; plate tectonics; inert gas diffusion
Special Issues, Collections and Topics in MDPI journals

Dr. Mauricio Parra

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Guest Editor

Institute of Geosciences, University of Sao Paulo, São Paulo, Brazil
Interests: low temperature thermochronology; fission-track analysis; (U-Th)/He analyses; active orogenesis; basin analysis

Special Issue Information

Dear Colleagues,

We are pleased to announce the Special Issue titled “Tectonics of the Northern Andes: Geochronology, Geochemistry, Isotopic Tracing and Thermochronology”, focussed on applications of isotopic tools to investigate the geological evolution of the continental margin in northwestern South America.

Northwestern South America (Venezuela, Colombia, and Ecuador) has a protracted history spanning from the Precambrian development of the western Amazonian craton within Rodinia. Subsequent rifting and active margin magmatism within the Iapetus and Rheic Wilson Cycles, the Permian amalgamation and Triassic rifting of Pangaea and the subsequent interaction with the Pacific Ocean formed extensive tracts of rift- and arc-related rocks, as well as associated mineralised belts. Oceanic plateau rocks and overlying intra-oceanic arcs collided and accreted to South America during and after ~80 Ma, representing a significant period of growth in the continental crust. Terrane collision dismembered and modified the existing margin, drove extensive rock uplift, exhumation and surface uplift, and ultimately formed the Central American land bridge.

The purpose of this Issue is to review existing knowledge, and to collect original research and data that advance our knowledge about how continental margins have evolved over hundreds of millions of years, by focussing on northwestern South America. We invite original contributions on the application of isotopic techniques to investigate the geological evolution of northwestern South America. These include geochronological and geochemical studies, isotopic tracing and the application of thermochronology.

Dr. Richard Spikings
Dr. Mauricio Parra
Guest Editors

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Keywords

Northwestern South America
Tectonics
Geochronology
Thermochronology
Isotopic tracing
Geochemistry

Published Papers (2 papers)

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Research

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23 pages, 14096 KiB

Open AccessArticle

Late Cretaceous through Cenozoic Paleoenvironmental History of the Bagua Basin, Peru: Paleoelevation Comparisons with the Central Andean Plateau

by Federico Moreno, Carmala N. Garzione, Sarah W. M. George, Lauren Williams, Fabiana Richter and Alice Bandeian

Geosciences 2022, 12(6), 242; https://doi.org/10.3390/geosciences12060242 - 10 Jun 2022

Cited by 1 | Viewed by 2562

Abstract

Located in northern Peru, at the lowest segment of the Central Andes, the Bagua Basin contains a Campanian to Pleistocene sedimentary record that archives the local paleoenvironmental and tectonic history. We present new δ¹⁸O and δ¹³C signatures of pedogenic carbonate nodules from paleosols in the Campanian–Maastrichtian Fundo El Triunfo Formation and in the upper Eocene–middle Miocene Sambimera Formation to reconstruct the isotopic composition of paleo-meteoric water and the floristic biome. We compare these results to modern isotopic values from a newly obtained modern water transect to interpret the environmental evolution of this area and its relationship with the neighboring Eastern Cordillera. A ~2‰ δ¹⁸O depletion between the latest Cretaceous and the latest Eocene reflects a shift from a coastal to inland environment. A negative δ¹⁸O shift of ~3‰ from the middle Miocene to the present day reveals the establishment of the Eastern Cordillera as an orographic barrier for the moisture traveling westward, sometime after deposition of the top of the Sambimera Formation at ~13 Ma. A shift in the δ¹³C signature from ~−25‰ in the Campanian–Miocene deposits to ~−23‰ in modern–Holocene times suggests a change in biome from dominant C3 plants to a mixture of C3 and C4 plants. This environmental shift reflects both the late Miocene global C4 expansion and the transition to more arid conditions in the basin. The Campanian–middle Miocene environmental reconstruction of the Bagua Basin indicates a steady paleoelevation setting in the northernmost Central Andes during most of the Cenozoic and constrains the uplift of the Eastern Cordillera to the late Miocene–Pleistocene. This paleoelevation history contrasts with that of the Central Andean Plateau, which is characterized by two major episodes of surface uplift: early–middle Miocene and late Miocene–Pliocene. The contrasting modern topographic configuration of the Central Andean Plateau and the northernmost Central Andes gives rise to the question of what factors created such a dramatic difference in topographic evolution of the two regions that shared an overall common tectonic history. We discuss the possible factors responsible for this contrasting topographic configuration and suggest that the diachronous flat slab episodes are likely a major factor, resulting in greater shortening and crustal thickness and, ultimately, in earlier surface uplift episodes occurring in the Central Andean Plateau. Full article

(This article belongs to the Special Issue Tectonics of the Northern Andes: Geochronology, Geochemistry, Isotopic Tracing, and Thermochronology)

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Review

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32 pages, 14671 KiB

Open AccessReview

The Geochemical and Isotopic Record of Wilson Cycles in Northwestern South America: From the Iapetus to the Caribbean

by Richard Spikings and Roelant Van der Lelij

Geosciences 2022, 12(1), 5; https://doi.org/10.3390/geosciences12010005 - 22 Dec 2021

Cited by 3 | Viewed by 3025

Abstract

Isotopic and geochemical data delineate passive margin, rift and active margin cycles in northwestern South America since ~623 Ma, spanning from the Iapetus Wilson Cycle. Ultramafic and mafic rocks record rifting associated with the formation of the Iapetus Ocean during 623–531 Ma, while the initiation of subduction of the Iapetus and Rheic oceans is recorded by continental arc plutons that formed during 499–414 Ma, with alternating compressive and extensional stages. Muscovite ⁴⁰Ar/³⁹Ar dates suggest there may have been a phase of Carboniferous metamorphism, although this remains tentative. A Passive margin was modified by active margin magmatism that started at ~294 Ma and culminated with collisional tectonics that signaled the final stages of the amalgamation of western Pangaea. Early Pangaea fragmentation included back-arc rifting during 245–216 Ma, leading to a Pacific active margin that spanned from 213–115 Ma. Trench retreat accelerated during 144–115 Ma, forming a highly attenuated continental margin prior to the collision of the Caribbean Large Igneous Province at ~75 Ma. Full article

(This article belongs to the Special Issue Tectonics of the Northern Andes: Geochronology, Geochemistry, Isotopic Tracing, and Thermochronology)

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