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Stratigraphic studies of the Taniente Palet bog at the north-western corner of Isla de los Estados Tierra del Fuego, South America

Trondman, Anna-Kari (2007) In Dissertations in Geology at Lund University
Department of Geology
Abstract
Fourteen somewhat overlapping 1-m cores, forming a total sequence of about 10.90 metres, were retrieved
from Taniente Palet bog on Isla de los Estados, Argentina. The cores were described and correlated both
visually and by measuring magnetic susceptibility and loss on ignition. Twelve samples were also taken for radiocarbon
dating. The results were then interpreted and compared with those from other localities in the region. Comparisons
were also made on a more global scale.
The sequence from Taniente Palet bog mainly consists of peat of different humification degrees with some units
of minerogenic material. However, the bottom of the sequence is dominated by minerogenic material. Available
radiocarbon dates show that there is an... (More)
Fourteen somewhat overlapping 1-m cores, forming a total sequence of about 10.90 metres, were retrieved
from Taniente Palet bog on Isla de los Estados, Argentina. The cores were described and correlated both
visually and by measuring magnetic susceptibility and loss on ignition. Twelve samples were also taken for radiocarbon
dating. The results were then interpreted and compared with those from other localities in the region. Comparisons
were also made on a more global scale.
The sequence from Taniente Palet bog mainly consists of peat of different humification degrees with some units
of minerogenic material. However, the bottom of the sequence is dominated by minerogenic material. Available
radiocarbon dates show that there is an age-reversal at the bottom of the sequence, indicating re-deposition in this
part. The re-deposition was interpreted as reflecting a period of increased precipitation between around 7600 and
7500 cal. B.P. The inferred precipitation increase may have caused the stream connected to the bog to flood and
transport minerogenic material eroded from bedrock and/or till, as well as older peat eroded from upstream, down
to Taniente Palet bog. It is possible that the precipitation increase at this time reflects a more southerly position of
the southern westerlies. After around 7500 cal. B.P. the heavy precipitation is believed to have ceased. However,
results indicate that changes in climatic conditions may also have occurred at around 6500, 5200, 1400 and 600 cal.
B.P. Data indicate that the medieval warm period (MWP) and the little ice age (LIA) also may be registered in the
sequence. The suggested climatic changes at Taniente Palet bog appear to correlate relatively well with inferred
climatic changes at other localities in southern Tierra del Fuego and in the South Atlantic region. In addition, the
results from Taniente Palet bog may also support the idea of a Holocene bipolar seesaw climate effect. (Less)
Abstract (Swedish)
Fjorton, något överlappande, en meter långa borrkärnor har tagits från mossen Taniente Palet
bog på ön Isla de los Estados, belägen i Tierra del Fuego i Argentina. De fjorton borrkärnorna bildar tillsammans en
hel sekvens på ungefär 10.90 meter. Borrkärnorna har beskrivits och korrelerats, både visuellt och med hjälp av
magnetisk susceptibilitet och glödförlust. Tolv prover har också tagits för åldersbestämning av sekvensen. Dateringen
har skett med hjälp av kol-14-metoden. Kol-14-åldrarna har sedan kalibrerats till kalenderår. Slutligen har
resultaten tolkats och jämförts med resultat från andra lokaler i regionen, men även mer globala jämförelser har
gjorts.
Sekvensen från Taniente Palet bog består främst av torv av olika... (More)
Fjorton, något överlappande, en meter långa borrkärnor har tagits från mossen Taniente Palet
bog på ön Isla de los Estados, belägen i Tierra del Fuego i Argentina. De fjorton borrkärnorna bildar tillsammans en
hel sekvens på ungefär 10.90 meter. Borrkärnorna har beskrivits och korrelerats, både visuellt och med hjälp av
magnetisk susceptibilitet och glödförlust. Tolv prover har också tagits för åldersbestämning av sekvensen. Dateringen
har skett med hjälp av kol-14-metoden. Kol-14-åldrarna har sedan kalibrerats till kalenderår. Slutligen har
resultaten tolkats och jämförts med resultat från andra lokaler i regionen, men även mer globala jämförelser har
gjorts.
Sekvensen från Taniente Palet bog består främst av torv av olika humifieringsgrad med minerogent material på
några nivåer. Botten av sekvensen domineras dock av minerogent material. Åldrarna i botten av sekvensen är omväxlande
unga och gamla, vilket indikerar att materialet på den här nivån har omlagrats. Omlagringen har tolkats
som att spegla en period med ökad nederbörd mellan ungefär 7600 och 7500 cal. B.P. Den antagna nederbördsökningen
kan ha orsakat en översvämning av bäcken, som är kopplad till mossen, och medfört att material eroderades
från berggrunden, moränen och andra torvmarker uppströms och sedan fördes med ner till Taniente Palet bog. Det
är möjligt att nederbördsökningen vid den här tiden berodde på en mer sydlig position av det sydliga västvindsbältet.
Nederbörden minskade troligen efter ungefär 7500 cal. B.P. Resultaten indikerar dock att det var förändringar i
klimatförhållandena även runt 6500, 5200, 1400 och 600 cal. B.P. Resultaten indikerar också att den medeltida värmeperioden
och lilla istiden kan vara registrerad i sekvensen. De föreslagna klimatförändringarna vid Taniente Palet
bog verkar korrelera relativt bra med antagna klimatförändringarna vid andra lokaler i södra Tierra del Fuego
och i den Sydatlantiska regionen. Dessutom antyder resultaten att en så kallad ”gungbrädeseffekt” av klimatet kan
finnas även under holocen. (Less)
Please use this url to cite or link to this publication:
author
Trondman, Anna-Kari
supervisor
organization
alternative title
Stratigrafiska studier av torvmarken Taniente Palet bog i det nordvästra hörnet av Isla de los Estados, Tierra del Fuego, Sydamerika
year
type
H1 - Master's Degree (One Year)
subject
keywords
Holocene, South America, Tierra del Fuego, peat, paleoclimate, holocen, Sydamerika, torv, paleoklimat
publication/series
Dissertations in Geology at Lund University
report number
216
language
English
id
2335499
date added to LUP
2012-01-31 15:42:48
date last changed
2012-01-31 15:42:48
@misc{2335499,
  abstract     = {{Fourteen somewhat overlapping 1-m cores, forming a total sequence of about 10.90 metres, were retrieved
from Taniente Palet bog on Isla de los Estados, Argentina. The cores were described and correlated both
visually and by measuring magnetic susceptibility and loss on ignition. Twelve samples were also taken for radiocarbon
dating. The results were then interpreted and compared with those from other localities in the region. Comparisons
were also made on a more global scale.
The sequence from Taniente Palet bog mainly consists of peat of different humification degrees with some units
of minerogenic material. However, the bottom of the sequence is dominated by minerogenic material. Available
radiocarbon dates show that there is an age-reversal at the bottom of the sequence, indicating re-deposition in this
part. The re-deposition was interpreted as reflecting a period of increased precipitation between around 7600 and
7500 cal. B.P. The inferred precipitation increase may have caused the stream connected to the bog to flood and
transport minerogenic material eroded from bedrock and/or till, as well as older peat eroded from upstream, down
to Taniente Palet bog. It is possible that the precipitation increase at this time reflects a more southerly position of
the southern westerlies. After around 7500 cal. B.P. the heavy precipitation is believed to have ceased. However,
results indicate that changes in climatic conditions may also have occurred at around 6500, 5200, 1400 and 600 cal.
B.P. Data indicate that the medieval warm period (MWP) and the little ice age (LIA) also may be registered in the
sequence. The suggested climatic changes at Taniente Palet bog appear to correlate relatively well with inferred
climatic changes at other localities in southern Tierra del Fuego and in the South Atlantic region. In addition, the
results from Taniente Palet bog may also support the idea of a Holocene bipolar seesaw climate effect.}},
  author       = {{Trondman, Anna-Kari}},
  language     = {{eng}},
  note         = {{Student Paper}},
  series       = {{Dissertations in Geology at Lund University}},
  title        = {{Stratigraphic studies of the Taniente Palet bog at the north-western corner of Isla de los Estados Tierra del Fuego, South America}},
  year         = {{2007}},
}