CSIC - Instituto de Ciencias de la Tierra Jaume Almera (ICTJA)
Abstract
[ES] Se caracterizan las facies de una sucesion de 2.250 m de potencia
de sedimentos carboniferos turbiditicos de la parte central del Priorato
(zona de las vilellas-Poboleda).
En 10s materiales paleozoicos de este area se distinguen tres unidades
IitoestratigrAficas carboniferas que integran el Complejo Turbidítico
del Prioraro y que yacen discordantes sobre 10s materiales
del Devdnico medio-superior (unidad 1). Los materiales de la unidad
inferior (unidad 2) se depositaron en un ambiente de talud - apron
y constan fundamentalmente de areniscas que intercalan niveles deslizados
de liditas, calizas y areniscas. Los depdsitos de las unidades
3 y 4 rnuestran diversas asociaciones de facies tipicas de ambientes
de abanico submarino profundo. La unidad 3 muestra facies de llanura
de cuenca y depositos arenosos de un canal intercalado. La unidad
4 esta constituida por tres megasecuencias negativas que corresponden
a otros tantos episodios de progradacion de un sistema de
lóbulo de abanico submarino.
Se discuten las relaciones entre las asociaciones de facies de las
tres unidades litoestratigraficas del complejo turbiditico y su asimilacidn
a unidades deposicionales dentro de modelos de sedimentaoidn
submarina.[EN] Facies characteristics are described for a 2.250 m thick succesion
of Carboniferous sediments which crops out along the Las Vilellas-
Poboleda road (central zone of El Priorato, Catalan Coastal Ranges).
In the studied area three main Carboniferous lithostratigraphic
units have been distinguished. The lower Carboniferous unit unconformably
overlie a basal Devonian unit (unit 1 or Vilellas unit),
which is formed by shales alternating with cherts and quarztose sandstones.
Unit 2 (Basetas unit) is mainly composed of lithic sandstones.
These caotic sediments are interpreted like deposits of a slopeapron
system.
Severa1 facies associations, typical from deep sea fan environments,
are recognized in the two uppermost units: outer fan facies and channel
deposits in the Scala Dei unit (unit 3) and distal lobe, proximal
non-channelized lobe and proximal channelized lobe facies associations
in the Poboleda unit (unit 4). The outer fan deposits consist
of monotonous shales with interbedded thin sandstones. A sandstone
level, 60 m thick, is found within this facies and has been interpreted
as channel deposits. The fan-lobe deposits are arranged in three
coarsening and thickening upward megasequences, 500 m thick each
one and reflect three major episodes of a fan system progradation.
The distal-fan lobe deposits are composed of medium to thick-bedded
classical turbidites (low density turbidite currents) internally organized
in thickening upward cycles too. The proximal, channelized
fan-lobe deposits are formed by amalgamated sandstones and pebbly
sandstones deposited through high density currents.
The entire sequence of the El Priorato Turbidite Complex seems
more likely originated by three well differenciated turbidite systems,
which were probably originated by palaeogeographic changes related
to tectonic and eustatic changes.Peer reviewe
