Integrated reconstruction of Holocene millennial-scale environmental changes in Tierra del Fuego, southernmost South America

Waldmann, Nicolás; Borromei, Ana María; Recasens, Cristina; Olivera, Daniela Flavia; Martínez, Mauro; Maidana, Nora I.; Ariztegui, Daniel; Austin, James A.; Anselmetti, Flavio S.; Moy, Christopher M.

doi:10.1016/j.palaeo.2014.01.023

Cited by 23 publications

(26 citation statements)

References 66 publications

(121 reference statements)

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“…Sediments of both investigated cores are predominantly clastic and composed of clay and silt, as well as fragmented and mostly centric diatoms (of the genus Discostella; Waldmann et al, 2014). XRD and SEM analyses reveal a monotonous and similar composition for both cores, regardless of the presence of laminae or other structures.…”

Section: Sediment Composition and Elemental Characteristicsmentioning

confidence: 87%

“…The high water transparency, but low algal biomass and nutrient content indicate an ultra-oligotrophic to oligotrophic status (Waldmann et al, 2014 and references therein). Further data collected in November 2006 revealed only small changes in pH (~7.8), temperature (~6°C) and oxygen content (~6-12 mg/l) in the water column and no significant thermocline establishment, which suggests well-mixed conditions during this early austral summer season (Waldmann et al, 2014). Mixing and oxygenation of the water column was likely induced by heavy precipitation prevailing at that time and leading to a ~1.5 m higher than normal lake level (Waldmann et al, 2014).…”

Section: Regional and Lake Settingsmentioning

confidence: 94%

“…Climate in Tierra del Fuego is sub-polar, with moisture originating from the Pacific Ocean, in relation to the SE Pacific subtropical anticyclone and the circum-Antarctic low-pressure belt (Rogers and Loon, 1982). During austral summers, intense precipitation and increased zonal winds are forced by the Southern Hemisphere Westerlies (SHW) that migrate southwards to the region (Lamy et al, 2001;Waldmann et al, 2014). The cold and relatively drier austral winters are mostly influenced by the Antarctic Oscillation (AO) system (Gong and Wang, 1999).…”

Section: Regional and Lake Settingsmentioning

confidence: 99%

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Cyclic preservation of Fe/Mn-redox fronts in sediments of an oligotrophic, ventilated deep-water lake (Lago Fagnano, Tierra del Fuego)

Neugebauer¹,

Thomas²,

Waldmann³

et al. 2018

Preprint

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Changing redox conditions in lakes are captured in their sediments, and are often influenced by climate. Their study therefore allows tracing past climate change on (sub-) annual to longer time-scales. In Lago Fagnano (54°S Argentina/Chile), an oligotrophic and deep-ventilated soft-water lake, cyclic alternations of light grey clay and dark green to black laminae are preserved throughout the Holocene sedimentary record. This study aims at clarifying the mechanism, frequency, and climatic forcing of laminae formation and preservation in Lago Fagnano, and their relation to changing redox conditions in the lake. Using high-resolution XRF scanning and mapping, thin section, XRD and SEM analyses of sediment cores, Fe- and Mn-oxides were identified as generating the lamination on (sub-) decadal time-scales. Black and greenish laminae are interpreted as buried palaeo-oxidation fronts that underwent early diagenetic processes. The burial of redox fronts in Lago Fagnano is most likely promoted by cyclic rapid increases of sedimentation due to higher runoff and mass-wasting events. Increased runoff is related to the strength of the Southern Hemisphere Westerlies that, in turn, is modified by climate oscillations. Therefore, it is suggested that the cyclic repetition of the buried palaeo-redox fronts, showing periodicities of ~52 and ~4.5 years in the western and eastern sub-basins of Lago Fagnano, respectively, is forced by climate modes. The most likely candidates are the Antarctic Oscillation (AO) and the El Niño Southern Oscillation (ENSO), both impacting southernmost South America and showing similar sub-decadal modes and multi-decadal variations. Although the burial of redox fronts in lake or marine sediments is well-known, this study is the first to present a record of cyclic, high-frequency recurrence of these fronts most likely triggered by changing climate.

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Section: Sediment Composition and Elemental Characteristicsmentioning

confidence: 87%

Section: Regional and Lake Settingsmentioning

confidence: 94%

Section: Regional and Lake Settingsmentioning

confidence: 99%

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Cyclic preservation of Fe/Mn-redox fronts in sediments of an oligotrophic, ventilated deep-water lake (Lago Fagnano, Tierra del Fuego)

Neugebauer¹,

Thomas²,

Waldmann³

et al. 2018

Preprint

Self Cite

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“…Many studies of Late Quaternary palaeoecological conditions from Isla Grande de Tierra del Fuego, southernmost Patagonia, were largely based on palynological records from terrestrial sediments Rabassa, 1987, 1995;heusser, 1989, 1998, 2003Markgraf, 1993;Borromei, 1995;Quattrocchio and Borromei, 1998;Mauquoy et al, 2004;Borromei et al, , 2010Borromei et al, , 2014Borromei and Quattrocchio, 2008;Markgraf and huber, 2010;Musotto, 2013;Waldmann et al, 2014;Musotto et al, 2016a, in press; among others works). Studies on dinocyst assemblages and palynofacies from Late Quaternary deposits of the southern South america are still limited to a few contributions (Borromei andQuattrocchio, 2001, 2007;Grill et al, 2002;Candel et al, 2009Candel et al, , 2011Candel et al, , 2012Rabassa et al, 2009;Candel, 2010;Fernández et al, 2014).…”

Section: Resumen Revisión De La Reconstrucción Paleoambiental De Secmentioning

confidence: 99%

Review of the Palaeoenvironmental Reconstruction of Late Quaternary Marine Sequences, Tierra Del Fuego (Argentina)

Candel

Borromei

2016

PEAPA

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Abstract. This work is an updated review of the knowledge on the evolution and development of palaeoenvironments during the holocene marine ingression and posterior regressive event in Tierra del Fuego. During the beginning of the marine transgression, ca. 8,000 cal yr BP, the vegetation in the southern coastal areas along the Beagle Channel was mainly arboreal with dominance of Nothofagus forest and scarcity of shrub and herbaceous communities, while in the northeastern atlantic coast, the treeless steppe was replaced by a relatively open Nothofagus forest. The early-Middle holocene aquatic assemblages were characterized by a scarce occurrence of marine components, especially dinoflagellate cysts, suggesting the development of low energy estuarine environments with low-salinities caused by glacier meltwater discharge. after 6,000 cal yr BP, an increase in the number of aquatic species was observed with dominance of Peridiniales dinoflagellate cysts, indicating the establishment of marginal marine environments with low to moderate salinities and high nutrient levels. During the last 1,000 cal yr BP, the littoral vegetation along the Beagle Channel showed an open Nothofagus forest and the development of peatlands, while in the northeastern atlantic coast the steppe vegetation developed under less humid environmental conditions related to the marine regressive event. These assemblages have a similar composition to those observed in modern sediments of the Beagle Channel and suggest palaeoenvironmental conditions comparable to today.

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“…Most of them offer information about the environments along the Canal Beagle (Heusser 1998(Heusser , 2003Markgraf and Huber 2010) and on the inner Fuegian Andean valleys (Markgraf 1993;Mauquoy et al 2004;Borromei et al 2007Borromei et al , 2010. In contrast, fewer palynological studies consider northern and central parts of Tierra del Fuego (Markgraf 1980;Heusser 1993Heusser , 2003Heusser and Rabassa 1995;Burry et al 2007;Musotto 2013;Waldmann et al 2014). Collectively, these studies show the development of an impoverished steppe-tundra vegetation with scattered trees after deglaciation, followed by a foreststeppe ecotone and a closed-canopy forest as a consequence of increased effective moisture of westerly origin (Heusser 2003;Markgraf and Huber 2010;Kilian and Lamy 2012).…”

Section: Introductionmentioning

confidence: 99%

Late Pleistocene and Holocene palaeoenvironmental changes in central Tierra del Fuego (~54°S) inferred from pollen analysis

Musotto

Borromei

Coronato

et al. 2015

Veget Hist Archaeobot

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A pollen record was obtained from a coring site at La Correntina mire (54°33 0 S, 66°59 0 W, 206 m a.s.l.) to the east of Lago Fagnano, centre of Tierra del Fuego.The results indicate that the valley bottom was free of ice shortly before 15,400 cal BP. Pioneer vegetation included dwarf shrub heaths, grasses and herbs with sparsely distributed Nothofagus trees, indicative of dry conditions. Nothofagus expanded by 10,000 cal BP and the foreststeppe ecotone was established by 9,400 cal BP, implying warm conditions and an increase in available moisture. After ca. 5,000 cal BP, the development of a closed-canopy forest is interpreted as the result of wetter and colder conditions. After 3,000 cal BP, Nothofagus forest became more open, and by about 400 cal BP there was a further decline of the forest. A closed-canopy Nothofagus forest re-established after 400 cal BP.

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Integrated reconstruction of Holocene millennial-scale environmental changes in Tierra del Fuego, southernmost South America

Cited by 23 publications

References 66 publications

Cyclic preservation of Fe/Mn-redox fronts in sediments of an oligotrophic, ventilated deep-water lake (Lago Fagnano, Tierra del Fuego)

Cyclic preservation of Fe/Mn-redox fronts in sediments of an oligotrophic, ventilated deep-water lake (Lago Fagnano, Tierra del Fuego)

Review of the Palaeoenvironmental Reconstruction of Late Quaternary Marine Sequences, Tierra Del Fuego (Argentina)

Late Pleistocene and Holocene palaeoenvironmental changes in central Tierra del Fuego (~54°S) inferred from pollen analysis

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