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| Titel |
Vegetation productivity during Termination III inferred from a speleothem δ13C record (Ejulve Cave, NE Spain) |
| VerfasserIn |
Carlos Perez-Mejías, Ana Moreno, Carlos Sancho, Miguel Bartolomé, Heather Stoll, Isabel Cacho, Hai Cheng, R. Lawrence Edwards |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250132123
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| Publikation (Nr.) |
 EGU/EGU2016-12601.pdf |
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| Zusammenfassung |
| The timing of Termination III, in contrast to TI and TII, is poorly known. Although TIII has
been described in pollen sequences from marine cores whose chronology was tuned to orbital
parameters, only few continental records with absolute dates have been published. Then, new
records of this period are particularly required to test the hypothetical synchronicity at
planetary scale of this event or to explore leads and lags between different proxies. Here we
present the record of ARTEMISA stalagmite from Ejulve cave (NE Spain) that covers
this period with exceptional resolution and constrained by a robust chronological
framework obtained from 24 U-Th dates. The largest shift in δ13C record (3 per mil
of variation) occurs at 241±2.3 kyr evidencing the TIII inception, in agreement
with both Sanbao Cave record in China (within age uncertainties) and the shift
to interglacial values of CH4 and CO2 in Antarctica, thus supporting its global
synchrony.
Interpreting δ13C data in Ejulve Cave is supported by 3 years of monitoring tasks
allowing the association of this proxy with vegetation productivity. Thus, more positive
values of δ13C, together with higher values in Mg/Ca and Sr/Ca in present-day farmed calcite
occurred during dry summer seasons. Besides, these periods are also characterized by the
lowest amount of calcite precipitating in the cave. On the contrary, more negative values are
obtained during wetter periods, even if they are cooler, showing the highest calcite
precipitation rates. During TIII, a spectacular increase in growth rate in the stalagmite is
observed, that reaches its maximum (20-30 mm/kyr) during the following 4 kyr.
Coherently, both δ13C and trace elements ratios (Mg/Ca and Sr/Ca) mark an increase in
humidity at 242 kyr that would last until 227 kyr BP delineating the duration of Stage
7e in this Mediterranean region. Other dry events highlighted by this record are
shown at 247 kyr, 245-243 kyr and 221-219 kyr BP suggesting periods of forest
reduction.
Ejulve speleothem represents the first time that TIII is described through δ13C variation
enriching the discussion about the timing and duration of humidity phases during that
glacial-interglacial transition. Besides, Ejulve record, in coherence with other records such as
Sanbao Cave, marks the existence of a dry event before TIII, following a YD-III and BA-III
pattern, thus supporting the previously evidenced similarities between TI and TIII. |
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