The long Pleistocene record from the Pego-Oliva marshland (Alicante-Valencia, Spain)

Abstract

Seven borehole cores were analysed to reconstruct the Pleistocene evolution of the Pego-Oliva Basin (Mediterranean coast, Iberian Peninsula). A total of 295 samples were recovered for amino acid racemization (AAR) dating, and 77 samples for sedimentological, palaeontological and biomarker determination, with two objectives: (1) to establish a chronological framework (especially for Middle Pleistocene); and (2) to obtain data on the palaeoenvironment.AAR proved that the record covers approximately 650 ka in which no important hiatuses occurred, although minor ones cannot be discarded. AAR provided valuable information on differential subsidence rates, and Marine Isotope Stages (MISs) 15–1 were identified.Litho- and biofacies allowed the identification of distinct palaeoenvironments through time, with the constant presence of a marsh/lagoonal environment with brackish or saline water with continental or marine influence. Remains of marine molluscs allowed the determination of periods of highstand sea level. Biomarkers indicated a constant input from terrestrial plants, and allowed definitions of periods with variable water mass and environmental moisture. As in other Mediterranean littoral areas, facies with a marine influence occurred mainly during odd MISs, indicating periods of highstand sea level. In contrast, alluvial-fan progradation and continental brackish wetlands developed during even MISs.

Benthic foraminifera and environmental changes in the Quaternary of the western Mediterranean coast: the core of Xeraco, Valencia, Spain

“…In the Pego Quaternary lagoon (about 20 km SE from Xeraco) four different cores have been studied (Dupré et al, 1988;Mateu, 1989;Viñals et al 1989;García-Forner, 1997;Torres et al, 2014). Two transgressive episodes, tentatively dated as MIS-5, have been recognized, with marine sediments (including foraminifera tests) transported into the lagoon, alternating with phases characterised by an enclosed lagoon environment with freshwater or brackish conditions, in which case foraminifers like A. beccarii, H. germanica or C. excavatum are predominant.…”

“…Although the Lower Pleistocene is poorly represented in the Valencian Community (some deposits possibly belonging to this epoch have been preserved in cliff sections, see Fumanal, 1995), the Middle Pleistocene (Marine Isotopic Stages 9 to 6) has been found in tectonically stable areas, such as in Xàbia (Usera et al, 1990a;Fumanal et al, 1991Fumanal et al, , 1993Usera & Mateu, 1995;García-Forner, 1997) or Oliva-Pego (Viñals, 1996;García-Forner, 1997;Torres et al, 2014), where the stratigraphic record of the subsurface deposits shows two marine positive pulses alternating with continental sedimentation. The Upper Pleistocene (Marine Isotopic Stages MIS-5 to MIS-2) is easily identifi ed in all the coastal sectors in Xàbia (Fumanal et al, 1993;García-Forner, 1997), Pego (Dupré et al, 1988;Mateu, 1989;Viñals et al, 1989;García-Forner, 1997) and Elx (Blázquez, 2005;Blázquez & Usera, 2010).…”

The MIS 5 palaeoenvironmental record in the SE Mediterranean coast of the Iberian Peninsula (Río Antas, Almería, Spain)

“…This area around the mouths of the Aguas and Antas rivers hosts a series of Pleistocene-age marine deposits that mark the eastern edge of the marine Vera Basin Figures (Fig. 1), which can be age-correlated in spite of they were subjected to strong neotectonic processes (Torres et al, 2000a(Torres et al, , 2006(Torres et al, , 2010a(Torres et al, , 2013. In fact, in the immediate neighborhood of the SRA, a stripe representing an ancient barrier system (MIS5) and running parallel to the present day coastline is clearly visible in Fig.…”

“…In many areas of the Mediterranean coast -Spain, Morocco, Tunisia -the current morphology appears as a series of cliffs where Alpine tectonics-linked parallel ranges reach the sea alternating with lagoons and wetlands. Some of the Quaternary coastal deposits of the Spanish Mediterranean realm have been studied, mostly focusing on raised marine deposits and addressed faunal remains and radiometric ages Hillaire-Marcel et al, 1986;Causse et al, 1993;Zazo, 1999;Zazo et al, 2003;Dabrio et al, 2011) and amino acid chronology (Hearty, 1986(Hearty, , 1987Hearty et al, 1986;Torres et al, 2000aTorres et al, , 2010aOrtiz et al, 2004a pear in the Elche Basin (Blázquez, 2005, Blázquez andUsera, 2010) and Pego Basin (Dupré et al, 1988;Mateu, 1989;Viñals et al, 1989;Hernández-Ruiz et al, 1993;Viñals and Fumanal 1995;Viñals, 1996;Mateu et al, 1997;Torres et al, 2013), sequences belonging to MIS5 are present as loosely cemented sands. Consequently, the core recoveries are low and the grain size is not favorable for paleoenvironmental recording.…”

General considerations and highlights of low-lying coastal zones: passive continental margins from the poles to the tropics

“…Anzidei et al (2014) analyse with geophysical, geomorphologic and archaeological methods the variation in sea-level related to all these factors. In the same basin there are also tectonically passive coasts and along one of these in eastern Spain a very long core is studied by Torres et al (2013), illustrating the environmental variations from mid-Pleistocene to the Recent.…”