Aleutian terranes from Nd isotopes

A number of regional terrane reconstructions conflict with inferred global plate history or with data from adjacent regional studies. Global plate tectonic reconstructions have ignored terranes until recently, and as a result are over-simplified. This paper represents a progress report on an attempt to "marry" Mesozoic global plate reconstructions and terrane analysis to produce examples of a "third generation" of global plate tectonic maps. The best approach to such an endeavor involves reiterative intercomparison of all regional data amongst each other and with the evolving global model. Data conflicts within and between terranes and regions must be resolved by a system of relative reliability "weighting". For the purpose of completing a global tectonic synthesis, the most reliable and useful data are those which constrain "departure" (rift) and "arrival" (collision/accretion) times. Certain ad hoc decisions aid in the analysis; for example, plates and their terrane passengers are constrained to move at half-spreading rates of less than 20 cm/yr, and only one net vector is allowed per plate. Inspection of the maps produced for this progress report suggests the following preliminary results: 1) more than 100 terranes and microcontinents are required to explain Mesozoic tectonic history; 2) terranes were continuously added to the plate tectonic gristmill throughout the Mesozoic; 3) there were at least two major types of continental rifting operating in the Mesozoic: spalling-off of "chips off the old blocks", and late propagation of rifts into the centers of continents to produce their breakup and dispersion; 4) it may not be necessary to invoke breakup of the "Pacifica" and "Cimmerian" continents; 5) a number of large islands drifted across climate zones in the Mesozoic; and 6) it is possible to reconcile seemingly contradictory terrane histories using relative data reliability weighting, simple plate motions and normal spreading rates. These results demonstrate the applicability of "third generation" plate history analysis and mapping techniques.

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“…This could be tested by isotopic provenance mapping [cf. Kistler, 1978;Kay et al, 1986;Aleinikoff et al, 1987;Bennett & DePaolo, 1987].…”

Section: The Florida Straits Block Was Proposed Bymentioning

confidence: 98%

Global Mesozoic Reconstructions Using Revised Continental Data and Terrane Histories: A Progress Report

Wilson

Rosol

Hay

2013

Deep Structure and Past Kinematics of Accreted Terranes

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“…4 and5 in Kelemen et al, 2003b, 2014), with the exception of the tholeiitic Finger Bay pluton on Adak Island. Isotopic differences between plutons and lavas have been inferred previously based on a small number of samples (Kay et al, 1986).…”

Section: Central-eastern Aleutian Plutons and Lavas Are Derived From mentioning

confidence: 99%

Distinctly different parental magmas for calc-alkaline plutons and tholeiitic lavas in the central and eastern Aleutian arc

Cai

Rioux

Kelemen

et al. 2015

Earth and Planetary Science Letters

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“…Global comparison of Talamanca intrusive rocks, other arc plutonic rocks, and reference compositions of sodic (Na) and potassic (K) TTGs (Moyen, 2011) and Upper Continental Crust (Rudnick & Gao, 2003). Kagalaska pluton from Fraser and Barrett (1959), Citron (1980), Kay et al (1983), Kay et al (1986Kay et al ( , 1990, Romick et al (1990), Tsvetkov (1991, Yogodzinski et al (1995), and Cai et al (2015). Kagalaska pluton from Fraser and Barrett (1959), Citron (1980), Kay et al (1983), Kay et al (1986Kay et al ( , 1990, Romick et al (1990), Tsvetkov (1991, Yogodzinski et al (1995), and Cai et al (2015).…”

Section: Geochemistry Geophysics Geosystemsmentioning

confidence: 99%

The Record of the Transition From an Oceanic Arc to a Young Continent in the Talamanca Cordillera

Gazel

Hayes

Ulloa

et al. 2019

Geochem Geophys Geosyst

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The Talamanca Cordillera in the Central America Arc (Costa Rica‐Panama) preserves the record of the geochemical evolution from an intraoceanic arc to a juvenile continental arc in an active subduction zone, making it a testbed to explore processes that resulted in juvenile continental crust formation and explore potential mechanisms of early continental crust generation. Here we present a comprehensive set of geochronological, geochemical, and petrological data from the Talamanca Cordillera that tracks the key turning point (12–8 Ma) from the evolution of an oceanic arc depleted in incompatible elements to a juvenile continent. Most plutonic rocks from this transition and postintrusive rocks share striking similarities with average upper continental crust and Archean tonalite, trondhjemite, and granodiorite. We complement these data with seismic studies across the arc. Seismic velocities within the Caribbean Plate (basement of the arc) show a relatively uniform lateral structure consistent with a thick mafic large igneous province. Comparisons of seismic velocity profiles in the middle and lower crust beneath the active arc and remnant Miocene arc suggest a transition toward more felsic compositions as the volcanic center migrated toward the location of the modern arc. Seismic velocities along the modern arc in Costa Rica compared with other active arcs and average continental crust suggest an intermediate composition beneath the active arc in Costa Rica closer to average crust. Our geochemical modeling and radiogenic isotopes systematics suggest that input components from melting of the subducting Galapagos hotspot tracks are required for this compositional change.

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Aleutian terranes from Nd isotopes

Cited by 82 publications

References 27 publications

Global Mesozoic Reconstructions Using Revised Continental Data and Terrane Histories: A Progress Report

Global Mesozoic Reconstructions Using Revised Continental Data and Terrane Histories: A Progress Report

Distinctly different parental magmas for calc-alkaline plutons and tholeiitic lavas in the central and eastern Aleutian arc

The Record of the Transition From an Oceanic Arc to a Young Continent in the Talamanca Cordillera

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