The late Pliocene palaeoenvironments and palaeoclimates of the western Iberian Atlantic margin from the Rio Maior flora

Abstract

Using a revised chronology, a new palynological study on the late Pliocene (Piacenzian and earliest Gelasian) Rio Maior site of the Tagus Basin in western Portugal has been undertaken from the F98 core. Combining light microscopy and scanning electron microscopy, a total of 127 different pollen and spore taxa have been identified from the Piacenzian Lake and indicate the presence of a subtropical to warm-temperate mixed forest during the majority of the Piacenzian (3.6-2.8 Ma). It is only in the latest Piacenzian (after 2.8 Ma) that progressive extinctions of climate sensitive taxa and a drop in diversity indicate a cooling and drying climate trend that has also been recorded from high-latitude localities. By the earliest Gelasian (2.58 Ma), a low diversity Ericaceae and Pinus dominated vegetation remained. The Piacenzian flora of Rio Maior also shows fluctuations in the presence of climate sensitive taxa and pollen-spore diversity that may be related to Piacenzian glaciations.

Electron spin resonance dating of the culminant allostratigraphic unit of the Mondego and Lower Tejo Cenozoic basins (W Iberia), which predates fluvial incision into the basin-fill sediments

“…Cosmogenic (burial isochron) dating was also used to date the UBS13 unit in the Alvalade Cenozoic Basin, namely at Vila Nova de Mil Fontes (~4 Ma;Ressurreição, 2018) and Sagres promontory (~1.8 Ma; Figueiredo, 2014). Palynological studies also indicated a latest Zanclean to Gelasian age for the aggradation interval of UBS13 (Diniz, 1984;Vieira, 2009, Vieira et al, 2018.…”

“…According to the records of fossil pollen content of the UBS13 sedimentary succession (Diniz, 1984(Diniz, , 2003Vieira, 2009, Vieira et al, 2018Pais et al, 2010;Diniz et al, 2016), a hot and wet climate prevailed during the latest Zanclean and the Piacenzian, with little seasonal contrast and precipitation probably in excess of 1000 mm per year in the less hot seasons. The pollen content in the upper part of the succession records a transition to a less forested environment and cooler climate during the Gelasian.…”

The Miocene: The Future of the Past

“…However, these forests progressively lost thermophilous and humid‐loving elements in response to continued cooling and decreasing availability of growing season moisture (Donders et al., 2009; Martinetto et al., 2017). The youngest of these “warm‐wet” floras are reported from the Plio‐Pleistocene of Italy (Martinetto et al., 2017) and Pliocene of Portugal (Vieira et al., 2018) and suggest a southwards contraction in their European distribution during the late Miocene to points of refugia proximal to the coasts (Vieira et al., 2018).…”

Palaeoclimate reconstruction and age assessment of the Miocene flora from the Trwyn y Parc solution pipe complex of Anglesey, Wales, UK

“…The botanical assignments of were first updated following Utescher and Mosbrugger (2010), Stuchlik et al (2001;2002; Author accepted version of manuscript accepted in Palynology: https://doi.org/10.1080/01916122.2021.1916636 4 2009; 2014) and Pound and Salzmann (2017). Although it has faced some criticism, the CA continues to be widely used largely due to its simplicity of the technique and consistency of reconstructions from it (Utescher et al 2014;Vieira et al 2018). The reconstructed palaeoclimate of Trwyn y Parc was then compared to CA reconstructions of Germany (Mosbrugger et al 2005) and other northwest European sites (Pound et al 2012b;Burls et al 2021).…”