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| Titel |
Flowstones from SE Spain document a close relationship between North Atlantic temperature and precipitation in the Western Mediterranean between 7 and 112 ka |
| VerfasserIn |
Alexander Budsky, Denis Scholz, Regina Mertz-Kraus, Christoph Spötl, Luis Gibert, Klaus Peter Jochum |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250150385
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| Publikation (Nr.) |
 EGU/EGU2017-14842.pdf |
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| Zusammenfassung |
| Here we present three flowstone records from Cueva Victoria, SE Spain, covering the period
between Marine Isotope Stage (MIS) 5 and MIS 3, the Late Glacial and the Holocene. The
flowstones were precisely dated by the MC-ICPMS 230Th/U-method. In addition, stable
oxygen and carbon isotope ratios as well as trace element concentrations were determined at
high resolution (centennial to decadal scale). Present-day climate of SE Spain is classified as
semi-arid with dry summer months (<10 mm/month precipitation) and sparsely developed
vegetation.
A large dataset of 230Th/U ages on several flowstones from Cueva Victoria
indicates preferential flowstone growth during warm phases (i.e., interglacials as
well as warm interstadials), whereas flowstone growth is interrupted during glacial
phases (Budsky et al., 2015). One of the drill cores shows more or less continuous
flowstone growth between the Last Interglacial (MIS 5) and MIS 3 (112 – 46 ka). A
flowstone from another part of the cave only records the time span from 86 to 50 ka
including several growth interruptions. However, both flowstones cover the transition
from MIS 4 to 3 including D/O events 17 to 13 at high resolution. Each D/O event
is reflected by a remarkable decrease in both δ18O and δ13C values (both up to
3‰ ) accompanied by decreasing concentrations of Mg and Sr. In particular, longer
D/O events, lasting several thousands of years (e.g., D/O 14, 19, 20 and 21), are
well represented in the δ18O and δ13C records. The timing is in good agreement
with the NGRIP ice core and sea-surface temperatures from the Iberian margin.
δ18O values are around -3.5 ‰ and decrease to -5 to -6 ‰ during D/O events,
while δ13C values are around -9 ‰ and decrease to -10 to -11 ‰ ) during D/O
events. We interpret these changes as more humid conditions during D/O events,
with elevated sea-surface temperatures in the North Atlantic and the Mediterranean
Sea leading to increased moisture transport and precipitation on the SE Iberian
Peninsula. As a consequence, vegetation density increased, which is reflected by
the decrease in δ13C values and Mg and Sr concentrations and an increase in P
content.
In the Holocene, the flowstone grew continuously from the Bølling/Allerød to the
mid-Holocene (7 ka). Stable isotopes record a trend of increasing temperatures with
decreasing values towards the mid-Holocene (δ18O ≈ - 6.4 ‰ , δ13C ≈ -11 ‰ ).
However, δ13C values record a significant excursion with elevated values (up to -3.8 ‰ )
during a period from 9.5 to 7.7 ka related to cold Bond-events in the North Atlantic, which is
interpreted as a dry period in SE Spain.
Budsky, A., Scholz, D., Gibert, L., Mertz-Kraus, R., 2015. 230Th/U-dating of the Cueva
Victoria flowstone sequence: Preliminary results and paleoclimate implications, in: Gibert,
L., Ferràndez-Canadell, C. (Eds.), Geology and Paleontology of Cueva Victoria. Mastia
11-13, Cartagena, pp. 101–109. |
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