TY - JOUR
T1 - Similarities between Archean high MgO eclogites and Phanerozoic arc-eclogite cumulates and the role of arcs in Archean continent formation
AU - Horodyskyj, Ulyana N.
AU - Lee, Cin Ty Aeolus
AU - Ducea, Mihai N.
N1 - Funding Information:
Undergraduate support for Horodyskyj came from Rice University and from NSF grants and a Packard Fellowship to Lee. Discussions with M. Barth, K. Burke, A. Lenardic, and C. J. O'Neill helped immensely. M. Barth is thanked for helping us amplify our eclogite and TTG database. J. Bedard and an anonymous reviewer provided helpful reviews. The opinions expressed in this paper reflect those of the authors only.
PY - 2007/4/30
Y1 - 2007/4/30
N2 - Some insights into the origin of cratonic mantle can be gained from "eclogite" (loosely defined here as an assemblage containing garnet and any pyroxene) xenoliths hosted in kimberlites erupted through Archean (~ 2.5-3.5 Gy) cratons. One subset of Archean eclogite xenoliths, the low MgO Archean xenoliths, is presently believed to represent metamorphosed fragments of ancient altered oceanic crust, leading to the suggestion that Archean cratons were built, at least in part, by the accretion of oceanic lithospheric segments. However, another Archean subset, the high MgO Archean eclogite xenoliths, have major and compatible trace-element (Ni and Cr) systematics similar to high MgO arc-eclogite xenoliths originating from the lithospheric root underlying the Sierra Nevada batholith in California, an example of a Phanerozoic arc. The Sierran high MgO arc-eclogites represent cumulates from hydrous basaltic magmas beneath a thick continental arc. The compositional similarities between the Archean and Sierran high MgO eclogites suggest that not only might the Archean high MgO eclogites have a cumulate origin, as has previously been suggested, but they may be arc-related. If so, Archean high MgO eclogites provide evidence from within the mantle roots of cratons that some form of arc magmatism contributed to the formation and evolution of Archean continents.
AB - Some insights into the origin of cratonic mantle can be gained from "eclogite" (loosely defined here as an assemblage containing garnet and any pyroxene) xenoliths hosted in kimberlites erupted through Archean (~ 2.5-3.5 Gy) cratons. One subset of Archean eclogite xenoliths, the low MgO Archean xenoliths, is presently believed to represent metamorphosed fragments of ancient altered oceanic crust, leading to the suggestion that Archean cratons were built, at least in part, by the accretion of oceanic lithospheric segments. However, another Archean subset, the high MgO Archean eclogite xenoliths, have major and compatible trace-element (Ni and Cr) systematics similar to high MgO arc-eclogite xenoliths originating from the lithospheric root underlying the Sierra Nevada batholith in California, an example of a Phanerozoic arc. The Sierran high MgO arc-eclogites represent cumulates from hydrous basaltic magmas beneath a thick continental arc. The compositional similarities between the Archean and Sierran high MgO eclogites suggest that not only might the Archean high MgO eclogites have a cumulate origin, as has previously been suggested, but they may be arc-related. If so, Archean high MgO eclogites provide evidence from within the mantle roots of cratons that some form of arc magmatism contributed to the formation and evolution of Archean continents.
KW - Archean
KW - Sierra Nevada
KW - craton
KW - eclogite
KW - garnet pyroxenite
KW - xenolith
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U2 - 10.1016/j.epsl.2007.02.006
DO - 10.1016/j.epsl.2007.02.006
M3 - Article
AN - SCOPUS:34047245279
VL - 256
SP - 510
EP - 520
JO - Earth and Planetary Sciences Letters
JF - Earth and Planetary Sciences Letters
SN - 0012-821X
IS - 3-4
ER -