Provenance of Cambro-Ordovician to Oligocene sandstones in the Southern Pyrenees, Spain

Abstract

The Cambro-Ordovician, Silurian and Devonian sedimentary sequences in the Southern pyrenees were deposited on the northern, then passive, margin of the early Iberian plate. Supply of an increasingly mature clastic assemblage was sourced from the south. In pre-Variscan Carboniferous time this margin was activated as is evident from the appearance of abundant metamorphic and volcanic lithics in the sandstones. The Variscan chain, which had emerged in the Late Westphalian, dictated a new clastic dispersal pattern with southwards-directed paleotransport. The sandstones of these early post-Variscan times typically represent a 'recycled orogen' facies with variations in composition that can be attributed to contemporaneous volcanism, relief and paleoclimate (Westphalian D - Early Triassic). Towards the end of the Mesozoic (Santonian) southern clastic sources, collectively referred to as the ,Ebro High', had again become active. They supplied stable terrigeneous assemblages until the end of the Maastrichtian' As a result of the Late-Cretaceous collision of Iberia with stable Europe, the main clastic dispersal systems changed drastically and in Paleocene time supply was from the northeast where uplifted Mesozoic carbonates were subjected to erosion. This dispersal system, which gradually also involved supply directly from the north and from deeper stratigraphic levels, became very important in Eocene and in Oligocene time, and, in essence, even persists today.