%0 Journal Article
%T Stratigraphic redefinition of the Zihuatanejo area, southwestern Mexico
%A Martini
%A Michelangelo
%A Ferrari
%A Luca
%A L車pez-Mart赤nez
%A Margarita
%A Valencia
%A Victor
%J Revista mexicana de ciencias geol車gicas
%D 2010
%I Universidad Nacional Aut車noma de M谷xico
%X the mesozoic volcano-sedimentary successions exposed in southwestern mexico have been traditionally grouped into the guerrero terrane, and interpreted to represent an allochthonous long-lived island arc or a complex multi-arc system accreted to the continental margin of north america. however, the nature of these arcs (intraoceanic versus continental), as well as the timing of the supposed accretion, are still debated. one of the key regions in this debate is that of zihuatanejo, where a cretaceous island arc (zihuatanejo arc) and associated accretionary complex (las ollas complex) have been defined in the past. in this paper we present a redefinition of the stratigraphy of the zihuatanejo region, based on field mapping supported by new 40ar/39ar and u-pb geochronology, which has significant implications for the cretaceous-paleogene evolution of the guerrero terrane. the lowermost stratigraphic levels of the zihuatanejo region are represented by the pre-cretaceous polydeformed and partly metamorphosed rocks of the las ollas complex and lagunillas formation. these rocks are unconformably overlain by the early cretaceous shallow marine playa hermosa arc assemblage. volcanic rocks of this assemblage are restricted to a few meters ofandesitic lavas interbedded with volcaniclastic sandstone and limestone, which suggests that the study area was in a peripheral position with respect to the main axis ofa magmatic arc. the rocks of the playa hermosa assemblage were uplifted by folding, eroded, and unconformably overlain by upper cretaceous continental to shallow marine rocks of the la uni車n-zihuatanejo assemblage, which are only gently folded. similar continental rocks (cutzamala formation) are exposed in the huetamo area, ~80 km northeast of zihuatanejo, and are interpreted as overlapping successions of the guerrero terrane. based on this correlation, we propose that the upper cretaceous la uni車n-zihuatanejo assemblage is not part of the tectono-stratigraphic guerrero terra
%K stratigraphy
%K guerrero terrane
%K la uni車n-zihuatanejo assemblage
%K zihuatanejo
%K mexico.
%U http://www.scielo.org.mx/scielo.php?script=sci_abstract&pid=S1026-87742010000300002&lng=en&nrm=iso&tlng=en