Sub-magmatic arc underplating by trench and forearc materials in shallow subduction systems; A geologic perspective and implications

Mihai N Ducea, Alan D. Chapman

Research output: Contribution to journalReview article

5 Citations (Scopus)

Abstract

Sedimentary rock units originally formed in subduction trenches are often found tectonically underplated directly below magmatic arc crustal sections along some segments of the ancient convergent margin of the North American Cordillera. During and immediately after tectonic underplating - which takes place during ultra-shallow subduction - magmatic arcs shut off completely or migrate suddenly inboard, thus leaving the underplated sections in the new forearc of the subduction system. A good modern equivalent is found in Southern Mexico where the Cocos plate subducts at shallow angle under North America. The process is episodic and corresponds to events of sudden trench inboard migration relative to the upper plate. If the trench sequence was dominated by quartz-rich material, the exposed rocks are schists; they display an inverse pressure-temperature path, suggesting that the crust collapsed and were exhumed immediately after the completion of this ablative process (Salinas type). If rich in feldspar, the trench-derived metasedimentary rocks are gneisses and display evidence for thermal relaxation-related heating and in some cases, partial melting (Skagit type). Feldspar-rich rocks presumably have a higher strength that precludes a quick gravitational collapse of the section. In both cases, this process leads to the complete reorganization of the crust with the addition of melt fertile, first cycle sedimentary materials in the deep crust of subduction systems.

Original languageEnglish (US)
Pages (from-to)763-779
Number of pages17
JournalEarth-Science Reviews
Volume185
DOIs
StatePublished - Oct 1 2018

Fingerprint

underplating
trench
subduction
crust
feldspar
Cocos plate
convergent margin
metasedimentary rock
cordillera
rock
schist
partial melting
sedimentary rock
melt
quartz
heating
tectonics
material
temperature

Keywords

  • Arc magmatism
  • Exhumation
  • Subduction systems
  • Tectonic underplating

ASJC Scopus subject areas

  • Earth and Planetary Sciences(all)

Cite this

Sub-magmatic arc underplating by trench and forearc materials in shallow subduction systems; A geologic perspective and implications. / Ducea, Mihai N; Chapman, Alan D.

In: Earth-Science Reviews, Vol. 185, 01.10.2018, p. 763-779.

Research output: Contribution to journalReview article

@article{dad8646c9db248bfb8d6b922a33f8d37,
title = "Sub-magmatic arc underplating by trench and forearc materials in shallow subduction systems; A geologic perspective and implications",
abstract = "Sedimentary rock units originally formed in subduction trenches are often found tectonically underplated directly below magmatic arc crustal sections along some segments of the ancient convergent margin of the North American Cordillera. During and immediately after tectonic underplating - which takes place during ultra-shallow subduction - magmatic arcs shut off completely or migrate suddenly inboard, thus leaving the underplated sections in the new forearc of the subduction system. A good modern equivalent is found in Southern Mexico where the Cocos plate subducts at shallow angle under North America. The process is episodic and corresponds to events of sudden trench inboard migration relative to the upper plate. If the trench sequence was dominated by quartz-rich material, the exposed rocks are schists; they display an inverse pressure-temperature path, suggesting that the crust collapsed and were exhumed immediately after the completion of this ablative process (Salinas type). If rich in feldspar, the trench-derived metasedimentary rocks are gneisses and display evidence for thermal relaxation-related heating and in some cases, partial melting (Skagit type). Feldspar-rich rocks presumably have a higher strength that precludes a quick gravitational collapse of the section. In both cases, this process leads to the complete reorganization of the crust with the addition of melt fertile, first cycle sedimentary materials in the deep crust of subduction systems.",
keywords = "Arc magmatism, Exhumation, Subduction systems, Tectonic underplating",
author = "Ducea, {Mihai N} and Chapman, {Alan D.}",
year = "2018",
month = "10",
day = "1",
doi = "10.1016/j.earscirev.2018.08.001",
language = "English (US)",
volume = "185",
pages = "763--779",
journal = "Earth-Science Reviews",
issn = "0012-8252",
publisher = "Elsevier",

}

TY - JOUR

T1 - Sub-magmatic arc underplating by trench and forearc materials in shallow subduction systems; A geologic perspective and implications

AU - Ducea, Mihai N

AU - Chapman, Alan D.

PY - 2018/10/1

Y1 - 2018/10/1

N2 - Sedimentary rock units originally formed in subduction trenches are often found tectonically underplated directly below magmatic arc crustal sections along some segments of the ancient convergent margin of the North American Cordillera. During and immediately after tectonic underplating - which takes place during ultra-shallow subduction - magmatic arcs shut off completely or migrate suddenly inboard, thus leaving the underplated sections in the new forearc of the subduction system. A good modern equivalent is found in Southern Mexico where the Cocos plate subducts at shallow angle under North America. The process is episodic and corresponds to events of sudden trench inboard migration relative to the upper plate. If the trench sequence was dominated by quartz-rich material, the exposed rocks are schists; they display an inverse pressure-temperature path, suggesting that the crust collapsed and were exhumed immediately after the completion of this ablative process (Salinas type). If rich in feldspar, the trench-derived metasedimentary rocks are gneisses and display evidence for thermal relaxation-related heating and in some cases, partial melting (Skagit type). Feldspar-rich rocks presumably have a higher strength that precludes a quick gravitational collapse of the section. In both cases, this process leads to the complete reorganization of the crust with the addition of melt fertile, first cycle sedimentary materials in the deep crust of subduction systems.

AB - Sedimentary rock units originally formed in subduction trenches are often found tectonically underplated directly below magmatic arc crustal sections along some segments of the ancient convergent margin of the North American Cordillera. During and immediately after tectonic underplating - which takes place during ultra-shallow subduction - magmatic arcs shut off completely or migrate suddenly inboard, thus leaving the underplated sections in the new forearc of the subduction system. A good modern equivalent is found in Southern Mexico where the Cocos plate subducts at shallow angle under North America. The process is episodic and corresponds to events of sudden trench inboard migration relative to the upper plate. If the trench sequence was dominated by quartz-rich material, the exposed rocks are schists; they display an inverse pressure-temperature path, suggesting that the crust collapsed and were exhumed immediately after the completion of this ablative process (Salinas type). If rich in feldspar, the trench-derived metasedimentary rocks are gneisses and display evidence for thermal relaxation-related heating and in some cases, partial melting (Skagit type). Feldspar-rich rocks presumably have a higher strength that precludes a quick gravitational collapse of the section. In both cases, this process leads to the complete reorganization of the crust with the addition of melt fertile, first cycle sedimentary materials in the deep crust of subduction systems.

KW - Arc magmatism

KW - Exhumation

KW - Subduction systems

KW - Tectonic underplating

UR - http://www.scopus.com/inward/record.url?scp=85051141876&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85051141876&partnerID=8YFLogxK

U2 - 10.1016/j.earscirev.2018.08.001

DO - 10.1016/j.earscirev.2018.08.001

M3 - Review article

AN - SCOPUS:85051141876

VL - 185

SP - 763

EP - 779

JO - Earth-Science Reviews

JF - Earth-Science Reviews

SN - 0012-8252

ER -