TILL MACROFABRIC AND GRAIN SIZE ANALYSIS OF GLACIAL DIAMICTONS IN THE SERRA DA CABREIRA MOUNTAINS, NW PORTUGAL

Till macrofabric and grain size analysis of glacial diamictons and landforms present in two valleys of the Serra da Cabreira Mountains in northwest Portugal were used to interpret diamictons types and to reconstruct the glacial paleo process history of this mountainous region. Supraglacial melt-out tills and debris flows deposits are dominant in this range. Supraglacial melt-out tills, representative of periods of glacial stability followed by recession, present weak fabric data and coarse, poorly sorted sediments. Debris flows deposits, representative of glacial or postglacial mass wasting activity, present very weak fabric data and very coarse, poorly sorted sediments. These glacial diamictons and landforms are of particular importance in the reconstruction of the glacial dynamics and history of the Serra da Cabreira Mountains due to a scarcity of chronological data based on absolute dating methods. These Atlantic mountains are also the lowest in elevation glaciated range in the Iberian Peninsula which makes them an interesting area to investigate mountain glacial dynamics in low elevation humid Atlantic coastal ranges and compare them with other Atlantic ranges.