TY - JOUR
T1 - Arclogites and their role in continental evolution; part 1
T2 - Background, locations, petrography, geochemistry, chronology and thermobarometry
AU - Ducea, Mihai N.
AU - Chapman, Alan D.
AU - Bowman, Emilie
AU - Triantafyllou, Antoine
N1 - Funding Information:
MND: I acknowledge support from US National Science Foundation grant EAR 1725002 and the Romanian Executive Agency for Higher Education , Research, Development and Innovation Funding project PN-III-P4-ID-PCCF-2016-0014 . I want to thank my students and postdocs Steven Kidder, Peter Luffi, Alan Chapman, Jay Chapman, Antoine Tryantafyllou, Robinson Cecil, Costi Balica, and Emilie Bowman for their contributions to arclogite science (direct or indirect), which are reflected in this paper. I thank my PhD adviser Jason Saleeby and my committee members Peter Wyllie, Hugh Taylor Jr. and Ed Stolper for guiding me in my early studies. I am forever indebted for the gracious reviews I received from Calvin Miller and Robert Kay on my early manuscripts: they were not just constructive they were career defining. I have learned a lot on the subject of this paper from some extraordinary peers that I am lucky to have within reach of an email or in the building: Cin-Ty Lee, Peter DeCelles, Claire Currie, George Bergantz, and George Zandt. ADC: I would like to thank my PhD advisor Jason Saleeby (yes, MND and I share the same academic parentage), who brought arclogites to my attention, and my coauthor for alerting me to the existence and significance of central Arizona arclogite xenolith localities. Support from NSF grant EAR-1524768 allowed myself and my amazing students Ojashvi Rautela, Jessie Shields, and Michael Murphy to study central Arizona arclogite nodules in more detail, for which I am grateful. This effort benefitted from field and laboratory assistance by D. Abboud, B. Hunter, and J. Thole and discussions with E. Chin, S. Esperança, C.-T. Lee, D. Smith. Formal reviews by E. Chin, W LeRoux and input from editor Arturo Gomez Tuena greatly improved the manuscript.
Funding Information:
MND: I acknowledge support from US National Science Foundation grant EAR 1725002 and the Romanian Executive Agency for Higher Education, Research, Development and Innovation Funding project PN-III-P4-ID-PCCF-2016-0014. I want to thank my students and postdocs Steven Kidder, Peter Luffi, Alan Chapman, Jay Chapman, Antoine Tryantafyllou, Robinson Cecil, Costi Balica, and Emilie Bowman for their contributions to arclogite science (direct or indirect), which are reflected in this paper. I thank my PhD adviser Jason Saleeby and my committee members Peter Wyllie, Hugh Taylor Jr. and Ed Stolper for guiding me in my early studies. I am forever indebted for the gracious reviews I received from Calvin Miller and Robert Kay on my early manuscripts: they were not just constructive they were career defining. I have learned a lot on the subject of this paper from some extraordinary peers that I am lucky to have within reach of an email or in the building: Cin-Ty Lee, Peter DeCelles, Claire Currie, George Bergantz, and George Zandt. ADC: I would like to thank my PhD advisor Jason Saleeby (yes, MND and I share the same academic parentage), who brought arclogites to my attention, and my coauthor for alerting me to the existence and significance of central Arizona arclogite xenolith localities. Support from NSF grant EAR-1524768 allowed myself and my amazing students Ojashvi Rautela, Jessie Shields, and Michael Murphy to study central Arizona arclogite nodules in more detail, for which I am grateful. This effort benefitted from field and laboratory assistance by D. Abboud, B. Hunter, and J. Thole and discussions with E. Chin, S. Esperan?a, C.-T. Lee, D. Smith. Formal reviews by E. Chin, W LeRoux and input from editor Arturo Gomez Tuena greatly improved the manuscript.
Publisher Copyright:
© 2020 Elsevier B.V.
PY - 2021/3
Y1 - 2021/3
N2 - Arclogites, or clinopyroxene-, garnet-, amphibole-, and Fe[sbnd]Ti oxide-bearing cumulates and restites (collectively representing residues) to andesitic continental arc magmas, are reviewed here and in a companion paper (Ducea et al., 2020). Experimental petrology and petrologic observations suggest that these eclogite facies rocks form magmatically in deep crustal hot zones beneath arcs with crustal thicknesses exceeding 35–40 km. Volcanic and plutonic products of thinner arcs may instead be entirely extracted from amphibolite to granulite facies and garnet-free pyroxenite residues. Arclogites are perhaps best known as xenoliths, with notable examples from young (Sierra Nevada and Central Arizona) and modern (Colombia) sub-arc environments. We suspect that arclogite occurs more commonly than currently recognized in the xenolith record from orogenic and cratonic domains. Arclogite is also found as discrete intervals in the deepest exposures of the Kohistan arc and as small volume inclusions in tectonically exposed peridotite massifs (e.g., Beni Bousera, Morocco). Geochemically, these rocks are low silica (SiO2 < 50%) assemblages with low Nb/Ta and Sr/Y ratios and enrichments in heavy REEs such that they represent the complement to the andesitic-dacitic liquids that make up the surface volcanics and batholiths of most arcs. Virtually all rock-forming minerals in arclogites are of similar or greater density than the underlying mantle, making them ideal candidates for foundering. Arclogites are formed in the lowermost crust of arcs at 35–70 km depth and record high temperatures (~800–1000 °C) at the time of formation which then cool and metamorphose at ~650–750 °C if they remain attached to the crust for an extended period of time. Ages of these rocks are obtainable by Sm[sbnd]Nd and Lu[sbnd]Hf garnet isochron geochronology as well as titanite or rutile U[sbnd]Pb geochronology, although these ages can be reset through long-term storage in hot lower crustal environments. Recent discovery of zircon accessory minerals in arclogites makes these rocks datable with greater precision and greater chance of preserving crystallization ages by U[sbnd]Pb chronology.
AB - Arclogites, or clinopyroxene-, garnet-, amphibole-, and Fe[sbnd]Ti oxide-bearing cumulates and restites (collectively representing residues) to andesitic continental arc magmas, are reviewed here and in a companion paper (Ducea et al., 2020). Experimental petrology and petrologic observations suggest that these eclogite facies rocks form magmatically in deep crustal hot zones beneath arcs with crustal thicknesses exceeding 35–40 km. Volcanic and plutonic products of thinner arcs may instead be entirely extracted from amphibolite to granulite facies and garnet-free pyroxenite residues. Arclogites are perhaps best known as xenoliths, with notable examples from young (Sierra Nevada and Central Arizona) and modern (Colombia) sub-arc environments. We suspect that arclogite occurs more commonly than currently recognized in the xenolith record from orogenic and cratonic domains. Arclogite is also found as discrete intervals in the deepest exposures of the Kohistan arc and as small volume inclusions in tectonically exposed peridotite massifs (e.g., Beni Bousera, Morocco). Geochemically, these rocks are low silica (SiO2 < 50%) assemblages with low Nb/Ta and Sr/Y ratios and enrichments in heavy REEs such that they represent the complement to the andesitic-dacitic liquids that make up the surface volcanics and batholiths of most arcs. Virtually all rock-forming minerals in arclogites are of similar or greater density than the underlying mantle, making them ideal candidates for foundering. Arclogites are formed in the lowermost crust of arcs at 35–70 km depth and record high temperatures (~800–1000 °C) at the time of formation which then cool and metamorphose at ~650–750 °C if they remain attached to the crust for an extended period of time. Ages of these rocks are obtainable by Sm[sbnd]Nd and Lu[sbnd]Hf garnet isochron geochronology as well as titanite or rutile U[sbnd]Pb geochronology, although these ages can be reset through long-term storage in hot lower crustal environments. Recent discovery of zircon accessory minerals in arclogites makes these rocks datable with greater precision and greater chance of preserving crystallization ages by U[sbnd]Pb chronology.
KW - Arc roots
KW - Arclogite
KW - Cumulates
KW - Residues
KW - Restites
KW - Thermobarometry
KW - U-Pb zircon geochemistry
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U2 - 10.1016/j.earscirev.2020.103375
DO - 10.1016/j.earscirev.2020.103375
M3 - Review article
AN - SCOPUS:85091504505
VL - 214
JO - Earth-Science Reviews
JF - Earth-Science Reviews
SN - 0012-8252
M1 - 103375
ER -