Early to middle Holocene palaeoenvironmental reconstruction of the Beagle Channel (southernmost Argentina) based on terrestrial and marine palynomorphs

Abstract

This paper presents the main palaeoenvironmental results obtained from a site located in the western sector of the Beagle Channel, Isla Grande de Tierra del Fuego, southernmost Argentina. The palynological analysis performed on marine sediments from Aserradero‐Lapataia 2 (latitude 54°51′22.7″S, longitude 68°34′22.8″W) allowed us to document the evolution of palaeoenvironmental conditions during the beginning of the Holocene marine transgression into the Beagle Channel. The results indicate that, prior to the marine incursion, the coastal areas were characterized by the presence of open‐grown shrubs and herbs along with woodland palaeocommunities. The aquatic environments were dominated exclusively by freshwater taxa. Around 8300 cal. a BP, seawater gradually flooded the channel while cold and high effective moisture conditions favoured the development of an arboreal vegetation with dominance of Nothofagus forest and scarcity of shrub and herbaceous communities. Gradually increasing salinities allowed the development of freshwater/marine transitional environments indicated by aquatic palynomorphs able to tolerate stressed conditions under fluctuating salinities. The increasing dinocyst diversification with dominance of heterotrophic taxa corroborates the establishment of a fully marine environment during the middle–late Holocene in the Beagle Channel.

Late Holocene Ameghinomya antiqua shells from the Beagle Channel: A multi-proxy approach to palaeoenvironmental and palaeoclimatic reconstruction

“…Also, palynological studies in Rio Ovando (Cormoranes Archipelago) in deposits from 4000 to 3000 yr B.P. register cold-water dinocyst assemblages, typical of marginal marine environments used as an indicator of warm waters in polar and sub-polar zones (Candel et al, 2009(Candel et al, , 2018. However, previous studies also support a salinity change scenario for the BC.…”

“…Seemingly, this salinity change was rather moderate. This assumption is based on the analyses of palynological and malacological assemblages in the area which show only slight changes when compared to stages of high saline variability (Candel et al, 2009(Candel et al, , 2013(Candel et al, , 2018Gordillo et al, 2005;Gordillo, 2009). Further studies, including higher numbers of specimens, more isotopic data and hence, a detailed calibration of A. antiqua δ 18 O shell values, are needed.…”

“…In the BC, several palaeoecological records have provided valuable palaeoclimatic proxies that have contributed to the reconstruction of Holocene climate and environmental change (Candel et al, 2009(Candel et al, , 2013(Candel et al, , 2018Gordillo et al, 2005;Gordillo, 2009;among others). However, the interpretation of stable isotope-derived palaeoclimatic information is often complex given the estuarine dynamics of the BC (Obelic et al, 1998;Isla et al, 1999;Gordillo et al, , 2015, and there is a need to improve, deepen and broaden the range of tools, to help to unravel the environmental history of the area.…”

Colonización Humana De Tierra Del Fuego: Contextos Arqueológicos Pretransgresivos en La Costa Norte Del Canal Beagle

“…AP. Al oeste de Ushuaia, en dos localidades ubicadas en la Bahía Lapataia (Bahía Lapataia y Aserradero-Lapataia 2), se registraron sedimentos marinos datados en 8478 años cal AP y 8278 años cal AP, respectivamente (Borromei y Quattrocchio 2007;Candel et al 2018). Sobre la costa norte del Canal Beagle, las altitudes de los niveles marinos elevados generados durante el máximo alcance de este evento transgresivo hace aproximadamente 7300-6700 años cal.…”

Past human populations and landscapes in the Fuegian Archipelago, southernmost South America

“…7420–7340 cal yr BP (calibrated after McCulloch and Davies, 2001) or at ca. 8300–6000 cal yr BP in southern areas (Candel et al, 2018), causing massive geomorphological and ecological transformations. Additionally, important volcanic eruptions impacted the Fuegian ecosystems during the Holocene (Fig.…”