RT Journal Article
T1 Geochemistry and U–Pb protolith ages of eclogitic rocks of the Ası´s Lithodeme,Piaxtla Suite, Acatla´n Complex, southern Mexico: tectonothermal activity alongthe southern margin of the Rheic Ocean
A1 Murphy, J. Brendam
A1 Keppie, J. Duncan
A1 Nance, R. Damian
A1 Miller, Brent V.
A1 Dostal, Jaroslav
A1 Middleton, Matt
A1 Fernández Suárez, Javier
A1 Jeffries, Teresa E.
A1 Storey, Craig D.
AB Recent data indicating that the Piaxtla Suite (Acatlán Complex, southern Mexico) underwent eclogite-facies metamorphism and exhumation during the Devono-Carboniferous suggest an origin within the Rheic Ocean rather than the Iapetus Ocean. The Ası´s Lithodeme (Piaxtla Suite) consists of polydeformed metasediments and eclogitic amphibolites that are intruded by megacrystic granitoid rocks. U–Pb (zircon) data indicate that the metasediments were deposited after c. 700 Ma and before intrusion of c. 470–420 Ma quartz-augen granite. The metasedimentary rocks contain abundant Mesoproterozoic detrital zircons (c. 1050–1250 Ma) and a few zircons in the range of c. 900–992 and c. 1330–1662 Ma. Their geochemical and Sm–Nd isotopic signature is typical of rift-related, passive margin sediments derived from an ancient cratonic source, which is interpreted to be the adjacent Mesoproterozoic Oaxacan Complex. Megacrystic granites were derived by partial melting of a c. 1 Ga crustal source, similar to the Oaxacan Complex. Amphibolitic layers exhibit a continental tholeiitic geochemistry, with a c. 0.8–1.1 Ga source (TDM age), and are inferred to have originated in a rift-related environment by melting of lithospheric mantle in the Ordovician. This rifting may be related to the Early Ordovician drift of peri-Gondwanan terranes (e.g. Avalonia) from Gondwana and the origin of the Rheic Ocean.
PB Geological Society, London
SN ISSN: 0016-7649, online ISSN: 2041-479X
YR 2006
FD 2006
LK https://hdl.handle.net/20.500.14352/52742
UL https://hdl.handle.net/20.500.14352/52742
LA eng
NO IGCP Project 497
DS Docta Complutense
RD 5 abr 2025