Raised marine sequences of Lanzarote and Fuerteventura revisited—a reappraisal of relative sea-level changes and vertical movements in the eastern Canary Islands during the Quaternary

Abstract

AbstraetSystematic mapping and morphosedimentary analysis of Fuerteventura and Lanzarote Islands supported by laboratory techniques (U-series mostly by TIMS, 14C analysis and allo-isoleucine measurements on biogenic carbonates from raised marine deposits, paleomagnetic and a few K/Ar measurements on vo\canic formations related to marine deposits) provide a basis for constraining the age of Late Cainozoic marine units. The most complete sequences of raised marine terraces are found at similar elevations in both islands. They inc\ude up to 12 marine terraces (Episodes) at elevations between O m and 70 m aboye mean sea level (asl). At least six terraces should be of Quaternary age, and more recent than 1.2 Myr. Throughout the whole marine sequence with the exception of the Holocene terrace, the warm fauna assemblage is characterized by the presence of Ostrea virleti, Nerita emiliana, and Strombus (S. cf. coronatus-S. cf. bubonius). However, there is a major change, highlighted by the disappearance of the first two species, below the 8-10 m terrace, that could possibly correspond to MIS 11. K-Ar measurements allow an estimate for mean uplift rate of 1.7 cm/ka during the last million years. The present elevation of the Last Interglacial deposits (about l and 2 m asl) shows discontinuous vertical movements with possibly a reverse trend since MIS 9 in eastern Canary Islands.

Sea level changes during the last and present interglacials in Sal Island (Cape Verde archipelago)

“…For the African coasts, faunal identifications from Lecointre (1965) Islands (Garda-Talavera, 1987Avila, 2000;Callapez and Ferreira Soares, 2000;Avila et al, 2002Avila et al, , 2008Garda-Talavera and Sanchez-Pinto, 2002;Meco et al, 2002;Zazo et al, 2002Zazo et al, , 2007. The palaeoecological requirements of the Sal Island fauna were recon structed by comparing our fossil data with observations of Morri and Bianchi (1995) and Morri et al (2000) on living shallow epibenthic communities.…”

“…Two highstands separated by an intervening period of lower sea level have been cited in the Canary Islands during the last intergiacial by Zazo et al (2002Zazo et al ( , 2003Zazo et al ( , 2004. Facies analyses suggest a moister climate at the beginning of the substage, as indicated by fan delta sedimentation.…”

“…In eastern Canary Islands Zazo et aL (2002Zazo et aL ( , 2003 recognized two morpho-stratigraphic units at elevations + 2 masl and + 1 masl in decreasing age order, separated by erosional features or terrestrial deposits indicative of a fall in sea level. A MI5 5.5 age has been deduced for these terraces using U-series measurements (23Drh age about 125 ka) and amino-acid racemization.…”

“…There are studies covering the Canary Islands (Meco et aL, 1997(Meco et aL, ,2002Zazo et aL, 2002Zazo et aL, , 2003Zazo et aL, , 2004 ( Steams and Thurber, 1965;Hoang et aI., 1978;Brlickner, 1986;Weisrock et al, 1999;Occhietti et al, 2002) using a variety of dating methods which made it possible to identify the last intergiacial deposits. This paper focuses on the last and present interglacial deposits.…”

Insect trace fossils in aeolian deposits and calcretes from the Canary Islands: Their ichnotaxonomy, producers, and palaeoenvironmental significance

“…The bioclastic grains came from marine deposits of the Quaternary, marine platforms. There are up two 12 levels of marine terraces situated from + 1 m to + 65-70 m above the present sea level (Zazo et al, 2002). These marine deposits were reworked by prevailing winds transporting sand grains, giving place to the formation of large dune fields in the easternmost Canary Islands.…”