Palynological approach in upper Quaternary terrestrial carbonates of central Italy: Anything but a ‘mission impossible’

Abstract

A palynological survey has been carried out on two late Quaternary travertine s.l. deposits of central Italy at Serre di Rapolano and Bagnoli (Tuscany region). The principal aim was to improve the understanding of factors that affect the accumulation and preservation of pollen grains in thermal (i.e. travertine) and ambient temperature (i.e. calcareous tufa) terrestrial carbonates. For this purpose, 52 526 pollen grains belonging to 118 pollen taxa from local to extra‐regional sources were analysed in 200 samples from different travertine and calcareous tufa lithofacies. Of these, 97 samples, generally from thermal travertines, were barren in palynomorphs. By contrast, pollen grains in the remaining samples were well‐preserved and did not show differential preservation features. These observations suggest that the pH of the solutions from which travertine or tufa precipitate is not a limiting factor in causing corrosion and/or destruction of pollen grains. Rather, the barrenness recorded in many samples appears to reflect a paucity of pollen rather than post‐depositional destruction. Results suggest that the depositional energy of the environment during the deposition of travertine plays an important role in controlling pollen concentration, as verified in both depressions (lower energy to higher pollen concentration) and slopes (higher energy to lower pollen concentration), respectively. Analysis of pollen data suggests that relatively high depositional temperatures and rates of carbonate deposition are also major limiting factors for efficient accumulation of pollen grains. Results of this study reveal that understanding pollen taphonomy processes in travertine and calcareous tufa is critical to developing accurate palaeoenvironmental and palaeoclimatic reconstructions.

Depositional system and palaeoclimatic interpretations of Middle to Late Pleistocene travertines: Kocabaş, Denizli, south‐west Turkey

“…The second palynoflora, from the middle part of the section, included Pinaceae ( Pinus and Abies ) and fewer amounts of grassland species (Asteraceae–Asteroideae and Chenopodiaceae) as well as other minor taxa ( Carpinus , Salix , Quercus , Oleaceae and Pterocarya ). According to previous studies, the high abundance of Pinus pollen were strongly related to altitudinal changes, latitudinal and longitudinal gradients, environmental setting, as well as transportation of pollen by water and/or wind (Markgraf, ; Jacobson & Bradshaw, ; Solomon & Silkworth, ; Sugita, ; Bertini et al ., ). However, the presence of Abies may indicate high topography near the deposition area (for example, Honaz Mountain) and/or climatic change.…”

“…Travertines, tufas and speleothems are environmental, hydrological, tectonic and climatological archives of the time span in which they formed (Andrews et al, 1997;Bar-Matthews et al, 1997;Hancock et al, 1999;Minissale et al, 2002;Andrews, 2006;Pedley, 2009;De Flippis et al, 2012;. To date, tufas and speleothems have been preferred to travertines for palaeoenvironmental and palaeoclimatic reconstructions (Boch et al, 2005;Andrews, 2006;Fairchild et al, 2006;Arenas et al, 2007Arenas et al, , 2010Bertini et al, 2007Bertini et al, , 2008Bertini et al, , 2014, mainly because stable isotopes in travertines are less predictable in terms of disequilibrium effects. For example, the d 13 C values of tufas and speleothems are influenced mostly by organic and atmospheric sources while the d 13 C values of travertines are governed mainly by thermal sources and the dissolution of basinal carbonates (Chafetz & Folk, 1984;Folk, 1993;Horvatincic et al, 2005;Pentecost, 2005;Andrews, 2006).…”

Palynological evidence of Middle Pleistocene palaeoenvironmental changes from the ‘Buca dell’Onice’ flowstone (Alpi Apuane, Central Italy)

“…In their review they confirm the potential of this natural archive to extract, in sufficient quantities, well-preserved palynomorphs, which are representative of contemporary vegetation on the surface permitting reconstruction of palaeovegetation. Further studies on Quaternary terrestrial carbonates, including travertine and calcareous tufa (Bertini et al, 2014;Carrión et al, 1999Carrión et al, , 2009Caseldine et al, 2008;Festi et al, 2016;Matley et al, 2020;Ricci, 2011;Ricci et al, 2015;Tagliasacchi & Kayseri-Özer, 2020;Toker et al, 2015), provided similar evidence reducing previous alleged biases and frequent misunderstandings regarding this peculiar natural archive. Glacials/stadials and/or interglacials/interstadials were traced by pollen records which sometimes provided unique information on both the vegetal landscape and climate parameters (e.g.…”

Palinoflora del Plioceno-Pleistoceno recuperada de los travertinos Villa Alegría y Cerro Prieto en el Valle de Tehuacán-Cuicatlán, México

“…Tradicionalmente se ha considerado que los travertinos no permiten una adecuada preservación de palinomorfos debido al ambiente (Bertini et al, 2014); no obstante, en varias de las muestras analizadas de ambas localidades de este estudio, se recuperaron más de 100 granos de polen y esporas de pteridofitas en buen estado de preservación, lo que implica que por gramo de sedimento se recuperaron de 1 a 3 granos de polen. En las capas de travertino de Villa Alegría y Cerro Prieto quedó registrada la evidencia de una rica vegetación que se estableció en la cuenca del VTC durante el Plioceno-Pleistoceno y que se reconstruyó en el presente trabajo a partir del registro palinológico (Figura 7-9, 15).…”