Stalagmites trace climate history and impact from volcanic eruptions


Date:
March 9, 2022
Source:
University of Go"ttingen
Summary:
The soils and vegetation of Patagonia's fjord regions form a unique
and highly sensitive ecosystem that is closely linked to marine
ecosystems, sediment deposition and carbon storage in the ocean. A
research team has been working on reconstructing the climate history
of this region in this extremely wet, rainy and inaccessible fjord
and island zone of the Patagonian Andes in southern Chile. Due to
its location, the area is a key region for understanding the history
of the southern westerly wind belt within the global climate system.



FULL STORY ==========================================================================
The soils and vegetation of Patagonia's fjord regions form a unique and
highly sensitive ecosystem that is closely linked to marine ecosystems, sediment deposition and carbon storage in the ocean. A research team,
including the University of Go"ttingen, has been working on reconstructing
the climate history of this region in this extremely wet, rainy and inaccessible fjord and island zone of the Patagonian Andes in southern
Chile. Due to its location, the area is a key region for understanding
the history of the southern westerly wind belt within the global climate system. The results were published in the journal Nature Communications
Earth & Environment.


==========================================================================
The research, in collaboration with the University of Trier, is based on extensive soil analyses and, above all, the detailed geochemical analyses
of a stalagmite that is around 4,500 years old, which was recovered
from an almost inaccessible cave. "This stalagmite is the southernmost limestone deposit of its kind ever found," says Professor Gerhard Wo"rner
of the Geoscience Center at Go"ttingen University. "Its fine and detailed stratification enables us to document the chemical composition of the stalagmite at high temporal resolution." Since the stalagmite formed over
a long time from surface waters that seeped into the cave, this geological "archive" makes it possible to reconstruct the climate-driven chemical processes in the peaty soils at the Earth's surface above the cave.

It turns out that the transport of chemical compounds from the peatlands
to the fjords in southern Patagonian fjords are particularly closely
coupled with natural processes in the delicate soil ecosystems, which
react highly sensitively to climate fluctuations and the input of volcanic
ash from nearby active volcanoes. "It was a surprise to discover actual remnants of volcanic dust from eruptions of nearby volcanoes in the
soil. In fact, tiny volcanic particles were detected embedded in the
stalagmite from the cave," Wo"rner explains. The effect of volcanic
depositions can also be documented from geochemical anomalies in the
stalagmite -- such as the high presence of sulphur -- and can even be attributed to individual volcanic eruptions by dating the stalagmite
layers. These volcanic deposits are of fundamental importance for the
chemical processes in the peatlands of Patagonia and have a particularly
strong effect under the influence of the extreme precipitation in
the region.

"These effects range from substantial destruction of vegetation after
large eruptions to a possible fertilizing effect on the ocean as a result
of nutrients released after smaller eruptions," Wo"rner adds.


========================================================================== Story Source: Materials provided by University_of_Go"ttingen. Note:
Content may be edited for style and length.


========================================================================== Related Multimedia:
* Patagonia_and_stalagmites ========================================================================== Journal Reference:
1. Bjo"rn Klaes, Gerhard Wo"rner, Katrina Kremer, Klaus Simon, Andreas
Kronz, Denis Scholz, Carsten W. Mueller, Carmen Ho"schen, Julian
Struck, Helge Wolfgang Arz, So"ren Thiele-Bruhn, Daniel Schimpf,
Rolf Kilian.

High-resolution stalagmite stratigraphy supports the Late Holocene
tephrochronology of southernmost Patagonia. Communications Earth &
Environment, 2022; 3 (1) DOI: 10.1038/s43247-022-00358-0 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/03/220309131853.htm

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