Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7452407 | Quaternary International | 2014 | 13 Pages |
Abstract
This study presents the characterization and numerical dating of Quaternary coastal deposits of NW Portugal, located between the mouths of the Minho and Neiva rivers. They record continental (small alluvial fans and streams) and transitional (aeolian dunes, interdune ponds, estuary, sandy and gravelly beaches) paleoenvironments. Quartz and K-feldspar optically stimulated luminescence (OSL) dating is employed as well as AMS 14C dating. A staircase of coastal terraces (abrasion shore platforms) was identified (altimetry, a.s.l.) and ascribed to the following probable Marine Isotope Stages (MIS): T1 - 20-18Â m (MIS11); T2 - ca. 13Â m (MIS9); T3 - 9.3-7.3Â m (MIS7); T4 - 5.5-4.5Â m (MIS5); T5 - 3.5-2.0Â m (MIS5). The terraces have some preserved sedimentary facies that includes coeval beach sediments on the lowest four. A late Pleistocene to Holocene sedimentary cover comprises four sub-units: a) the lower sub-unit, corresponding to ferruginous stream deposits and aeolian dunes dated ca. 67-61Â ka (MIS4), probably related with sub-humid to arid mid-cold conditions; b) on the slopes, the lower sub-unit is overlapped by sandy-silty colluvium and sandy alluvial deposits dated ca. 56-28Â ka (MIS3) and probably reflecting cold/mid-cold and wet/dry climate conditions; c) this sub-unit is topped by soliflucted lobes and sandy-silty/silty deposits recording cold and dry climate dated 20-13Â ka (MIS2), and d) a top sub-unit dated to 16-18th century, recording Little Ice Age events, consisting of fluvial sediments coeval with temperate climate evolving to aeolian dunes from the Maunder Minimum (cold windy dry conditions).
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Geology
Authors
Ricardo P. Carvalhido, Diamantino I. Pereira, Pedro P. Cunha, Jan-Pieter Buylaert, Andrew S. Murray,