%0 Journal Article
%T The Ordovician Quebrada Grande Formation, Cord車n de Lila (Antofagasta Region, northern Chile): stratigraphicand paleogeographic significance
%A Gonz芍lez
%A Javier
%A Niemeyer
%A Hans
%A Benedetto
%A Juan L
%A Brussa
%A Edsel D
%J Revista geol車gica de Chile
%D 2007
%I Scientific Electronic Library Online
%R 10.4067/S0716-02082007000200006
%X the cord車n de lila is located immediately to the south of the salar de atacama, in northern chile. the geology of the cord車n de lila is characterized by extensive outcrops of early paleozoic volcanic and sedimentary rocks (cord車n de lila igneous and sedimentary complex; cisl) that form the 'arco magm芍tico occidental' (amo) which is intruded by a multiple suite of middle ordovician to lower silurian granitoids. in this contribution we report the results of a sedimentological and paleontological study of a recently discovered 1,600 m thick marine ordovician sedimentary sequence (quebrada grande formation) which unconformably overlies the cisl. the quebrada grande formation comprises three mayor facies associations. in stratigrafic order, these facies associations are: matrix-supported conglomerates (1), interbedded sandstones and siltstones (2) and clast-supported conglomerates (3). facies association (1) is interpreted as debris flow deposits accumulated in a proximal marine fan-delta setting while the overlying sandstones and siltstones facies (2) represent open-marine platform deposits. clast-supported conglomerates (3) are the record of high-energy sedimentary episodes during which coarse sediments reached the distal part of the fan-delta. the detrital fraction of the quebrada grande formation is derived from the erosion of the cambrian?-lower ordovician? cisl volcanic arc, the plutonio roots of the arc and its continental basement. the age of this formation is well constrained by the occurrence of brachiopods (paralenorthis sp., monorthis transversa benedetto, and mollesella? sp.) near the base and graptolites (tetragraptus sp. and cryptograptus? sp.) towards the middle of the succession. both brachiopods and graptolites indicate an arenigian to early llanvirnian (darriwilian) age. the brachiopod assemblage from cord車n de lila displays affinities with the famatina basin fauna of western argentina. the absence of taxa in common between the amo and the nearby 'faja
%K ordovician
%K brachiopods
%K graptolites
%K arequipa-antofalla terrane
%K cord車n de lila
%K northern chile.
%U http://www.scielo.cl/scielo.php?script=sci_abstract&pid=S0716-02082007000200006&lng=en&nrm=iso&tlng=en