Diatom assemblage changes in lacustrine sediments from Isla de los Estados, southernmost South America, in response to shifts in the southwesterly wind belt during the last deglaciation

Fernández, Marilén; Björck, Svante; Wohlfarth, Barbaria; Maidana, Nora I.; Unkel, Ingmar; Putten, Nathalie Van der

doi:10.1007/s10933-013-9736-4

Cited by 28 publications

(16 citation statements)

References 58 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition to association with grain size, the Sr/Rb ratio is believed to reflect the relative contribution of physical and chemical weathering to detrital input, since Sr is more easily released from primary minerals and leached from the catchment than Rb (Fernández et al . 2013; Adamson et al . 2019).…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Shallow depositional basins as potential archives of palaeoenvironmental changes in southwestern Greenland over the last 800 years

Roman

Chattová

Lehejček

et al. 2020

Boreas

View full text Add to dashboard Cite

The Arctic, one of the most sensitive components of the Earth's climate system, experienced pronounced climatic fluctuations during the Late Holocene. In order to obtain a detailed record of past environmental and climatic variability, sedimentary cores from two interconnected infilled depositional basins in the Kobbefjord area, southwestern Greenland, were retrieved and subjected to a multi‐proxy investigation. The absolute chronostratigraphy was established through radiocarbon (14C) and short‐lived radioisotope (210Pb, 137Cs) dating. We also analysed magnetic susceptibility, grain size, X‐ray fluorescence element composition, total content of carbon, nitrogen and sulphur, biogenic silica and diatom assemblages. The palaeoenvironmental reconstruction presented from the upper basin records ~800 years of sedimentation in a former shallow Arctic lake/pond that was modulated by catchment processes and regional hydroclimate. The record is dominated by alternating periods of increased organic and clastic deposition, suggesting warmer/drier and colder/wetter climate, respectively. Comparison of our records with other proxy‐based lacustrine, marine and glacier records and instrumental measurements from Greenland and the North Atlantic reveals common climatic trends, consistent with the inferred North Atlantic Oscillation pattern. Periods at ~800–600, ~320–220 and ~140–30 cal. a BP correspond to the main cold phases. The earliest climatic deterioration coincides with the demise of the nearby Norse Western Settlement. The most recent cold period represents the culmination of the Little Ice Age with the maximum Holocene advances of Greenland glaciers. Ameliorated conditions predominated at ~550–320 and ~220–140 cal. a BP. The evolution of both water bodies is concluded by transition into oligotrophic peat bogs after complete infilling of the basins at ~30 cal. a BP. Despite differences in proxy signals between the coring sites, this study endorses the usefulness of shallow lake/pond sediments from infilled basins for environmental reconstructions, as long as local depositional processes do not mask the external driving factors.

show abstract

Section: Discussionmentioning

confidence: 99%

“…2004; Fernández et al . 2013). Together with high abundances of the small benthic fragilaroids ( Fragilariforma virescens (Ralfs) Williams and Round, Fragilaria capucina var.…”

Section: Discussionmentioning

confidence: 99%

Shallow depositional basins as potential archives of palaeoenvironmental changes in southwestern Greenland over the last 800 years

Roman

Chattová

Lehejček

et al. 2020

Boreas

View full text Add to dashboard Cite

show abstract

“…Rubidium (Rb) is a conservative element mainly associated with clay minerals where it often substitutes for K (Jin et al, 2006;Kylander et al, 2011;Heymann et al, 2013). In a humid climate, the content of Rb tends to be elevated due to a high precipitation and a subsequent increase of erosion and terrestrial input (Fernández et al, 2013;Heymann et al, 2013).…”

Section: X-ray Fluorescence Proxies Interpretationmentioning

confidence: 99%

Lake-Level Changes and Their Paleo-Climatic Implications at the MIS12 Lower Paleolithic (Middle Pleistocene) Site Marathousa 1, Greece

et al. 2021

View full text Add to dashboard Cite

Lithics and cut-marked mammal bones, excavated from the paleo-lake Marathousa 1 (MAR-1) sediments in the Megalopolis Basin, southern Greece, indicate traces of hominin activity occurring along a paleo-shoreline ca. 444,000 years (444 ka) ago. However, the local environment and climatic conditions promoting hominin activity in the area during the MIS12 glacial remain largely unknown. In order to reconstruct the paleo-environment including paleo-lake levels and governing paleo-climatic factors on a high temporal resolution, we analyzed a 6-meter-long sediment sequence from the archeological site MAR-1 and a Bayesian age model was computed for a better age constrain of the different sedimentary units. A multiproxy approach was applied using ostracods, sponge spicules, diatoms, grain sizes, total organic carbon, total inorganic carbon and conventional X-ray fluorescence analysis. The results from the site represent a protected region surrounded by high mountains under the constant influence of water, either as a shallow partly anoxic water body surrounded by reed belts (>463–457 ka, <434–427 ka), a riverine-lake deltaic system (∼457–448 ka), a floodplain (∼448–444 ka) or a seasonal freshwater pond (∼444–436 ka). The local changes of water levels resemble large trends and rhythms of regional records from the Mediterranean and appear to directly respond to sea surface temperature (SST) changes of the North Atlantic. In particular, when the SSTs are high, more moisture reaches the study area and vice versa. Additional water reaches MAR-1 through melting of the surrounding glaciers after brief warm phases during MIS12 in the Mediterranean realm, which leads to the formation of smaller fresh water ponds, where also the horizon of the excavated remains is placed. Such ponds, rich in ostracods and other microorganisms, provided mammals and humans valuable resources, such as potable water, a wide range of plant species and hunting opportunities. These deposits therefore bear a high archeological potential. The results from our study suggest that the Megalopolis Basin could have served as a refugium for hominins and other organisms due to its capacity to retain freshwater bodies during glacial and interglacial periods.

show abstract

“…changes in productivity, climate, precipitation and nutrient supply). In lacustrine sediment cores, BSi content can range from the detection limit (0.01 wt %) to > 70 wt % SiO 2 (Frings et al, 2014a). The downcore variations in BSi through time vary from as little as 2 wt % SiO 2 (Adams and Finkelstein, 2010;Ampel et al, 2008) to a high of 10-40 wt % SiO 2 (Johnson et al, 2011;Prokopenko et al, 2006;Van der Putten et al, 2015) and depends on several interacting factors such as mineral matter or organic matter accumulation, diatom productivity and preservation/dissolution processes.…”

Section: Implications For Palaeoecological Studiesmentioning

confidence: 99%

The contribution of tephra constituents during biogenic silica determination: implications for soil and paleoecological studies

Clymans¹,

Barão²,

Putten³

et al. 2015

Preprint

View full text Add to dashboard Cite

Abstract. Biogenic silica (BSi) is used as a proxy by soil scientists to identify biological effects on the Si cycle and by paleoecologists to study environmental changes. Alkaline extractions are typically used to measure BSi in both terrestrial and aquatic environments. The dissolution properties of volcanic glass in tephra deposits and their nano-crystalline weathering products are hypothesized to overlap those of BSi, however, data to support this behavior are lacking. The understanding that the Si-bearing fractions that dissolve in alkaline media (SiAlk) do not necessarily correspond to BSi, question the applicability of BSi as a proxy. Here, analysis of 15 samples reported as tephra-containing allows us to reject the hypothesis that tephra constituents produce an identical dissolution signal to that of BSi during alkaline extraction. We found that dissolution of volcanic glass shards is incomplete during alkaline dissolution. Simultaneous measurement of Al and Si used here during alkaline dissolution provides an important parameter to enable us to separate glass shard dissolution from dissolution of BSi and other Si-bearing fractions. The contribution from volcanic glass shard (between 0.2–4 wt.% SiO2), the main constituent of distal tephra, during alkaline dissolution can be substantial depending on the total SiAlk. Hence, soils and lake sediments with low BSi concentrations are highly sensitive to the additional dissolution from tephra constituents and its weathering products. We advise evaluation of the potential for volcanic or other non-biogenic contributions for all types of studies using BSi as an environmental proxy.

show abstract

Diatom assemblage changes in lacustrine sediments from Isla de los Estados, southernmost South America, in response to shifts in the southwesterly wind belt during the last deglaciation

Cited by 28 publications

References 58 publications

Shallow depositional basins as potential archives of palaeoenvironmental changes in southwestern Greenland over the last 800 years

Shallow depositional basins as potential archives of palaeoenvironmental changes in southwestern Greenland over the last 800 years

Lake-Level Changes and Their Paleo-Climatic Implications at the MIS12 Lower Paleolithic (Middle Pleistocene) Site Marathousa 1, Greece

The contribution of tephra constituents during biogenic silica determination: implications for soil and paleoecological studies

Contact Info

Product

Resources

About