Fossil planktonic foraminifera from the Agulhas region ... · Fossil planktonic foraminifera from...
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The work described in this poster & the research leading to these results has received funding from the European Community's Seventh Framework Programme FP7/2007-2013 – Marie-Curie ITN, under grant agreement n° 238512, GATEWAYS project. Acknowledgements to Saskia Kars for help with SEM images. 2b Fossil planktonic foraminifera from the Agulhas region over the last Glacial-Interglacial cycle: 1 , Frank Peeters 1 , Margit H. Simon 2 , Ian R. Hall 2 , Thibaut Caley 1 2 (1) Earth and Climate, Faculty of Earth and Life Sciences, VU University Amsterdam, The Netherlands (2) School of Earth and Ocean Sciences, Car diff University, Cardiff , United Kingdom [email protected] Aims Agulhas Leakage E fficiency and Polar Fauna Similarity Figure 1: downcore, with 1.0 meaning the fauna in both cores is excactly the same, while 0 means completely dissimilar samples. A similar fauna suggests the STF is south of core MD02-2588, while a dissimilar Approach Foraminifer abundance counts show glacial-interglacial variability in the Basin Record (1) to this record from the Indian Ocean, described as the upstream variability (fig. 1). Comparisons of local faunal changes at the (based on (3)) are used to compare the local faunal assemblag es (fig. 1). Conclusions The similarity comparison of the polar fauna between cores MD02-2588 and CD154 Figure 4: The Lisieki Raymo benthic isotope stack is used here for reference, to show the Marine Isotope Stages over the last 100 ka. The tropical-subtropical f auna (fig. 5) is shown for the three core sites (CD154 17-17K, MD02-2588 and CBR). This fauna is referred to as the Agulhas Leakage Fauna (ALF) at site CBR. The subpolar-polar fauna for each site is also shown (fig. 5). Glacial - Figure 3: adapted from (4), (2), and (5). The Agulhas Current is represented by AC by AR, Agulhas return current by ARC, Mozambique Current by MC, East Madagascar Current by EMC, Red Sea Intermediate Water by RSIW, Benguela Undercurrent by BU, and the North Brazil Current by NBC. CD154 17-17K shows the ‘typical’ upstream foraminifer assemblages of the CD154 17-17K CBR MD02-2588 The Story Foraminifer assemblages have been used in the past as a proxy for paleo-leakage (commonly known as the Agulhas Leakage Fauna, or ALF) (1). Normalizing the ALF to the upstream Agulhas Current fauna can provide increased accuracy in the assessment of the leakage, as it takes the south by the migratory Subtropical Front (STF) (fig. 3), which moves Agulhas Current Subtropical Front Agulhas Current Subtropical Front Interglacial (e.g. Holocene) Glacial (e.g. LGM) Figure 2: GATEWAYS Initial Training Network References - minifera deep-sea sediments.” 11(1): 15-35. Figure 5: The tropical- and the subpolar-polar fauna (right). 0 10 20 30 40 50 60 70 80 20 40 60 80 100 Age (ka) a n u a f l a c i p o r t b u s - l a c i p o r T ) % ( ) a n u a F s a h l u g A ( ) % ( a n u a F r a l o P - r a l o p b u S 2.5 3 3.5 4 4.5 5 5.5 2 4 T-1 0 20 40 60 80 100 0 ) o % ( O 8 1 d a r e f i n i m a r o f c i h t n e B 4 0 R L more less more less CD154 17-17K CD154 17-17K MD02-2588 MD02-2588 CBR CBR 0 0.2 0.4 0.6 0.8 0 20 40 60 80 100 Polar fauna similarity between CD154 17-17K and MD02-2588 1.0 Age (ka) 0 0.1 0.2 0.3 0.4 Agulhas Leakage Efficency 0.5 2 4 T-1 more less more less south STF north To show the upstream glacial-interglacial variability in the Agulhas Current foraminifer assemblages and the influence this has on the downstream
Transcript of Fossil planktonic foraminifera from the Agulhas region ... · Fossil planktonic foraminifera from...
The work described in this poster & the research leading to these results has received funding from the European Community's Seventh Framework Programme FP7/2007-2013 – Marie-Curie ITN, under grant agreement n° 238512, GATEWAYS project.Acknowledgements to Saskia Kars for help with SEM images.
2b
Fossil planktonic foraminifera from the Agulhas region over the last Glacial-Interglacial cycle:
1, Frank Peeters1, Margit H. Simon2, Ian R. Hall2, Thibaut Caley1 2 (1) Earth and Climate, Faculty of Earth and Life Sciences, VU University Amsterdam, The Netherlands
(2) School of Earth and Ocean Sciences, Cardiff University, Cardiff, United [email protected]
Aims
Agulhas Leakage Efficiency and Polar Fauna Similarity
Figure 1:
downcore, with 1.0 meaning the fauna in both cores is excactly the same, while 0 means completely dissimilar samples. A similar fauna suggests the STF is south of core MD02-2588, while a dissimilar
ApproachForaminifer abundance counts show glacial-interglacial variability in the
Basin Record (1) to this record from the Indian Ocean, described as the
upstream variability (fig. 1). Comparisons of local faunal changes at the
(based on (3)) are used to compare the local faunal assemblages (fig. 1).
Conclusions
The similarity comparison of the polar fauna between cores MD02-2588 and CD154
Figure 4: The Lisieki Raymo benthic isotope stack is used here for reference, to show the Marine Isotope Stages over the last 100 ka. The tropical-subtropical fauna (fig. 5) is shown for the three core sites (CD154 17-17K, MD02-2588 and CBR). This fauna is referred to as the Agulhas Leakage Fauna (ALF) at site CBR. The subpolar-polar fauna for each site is also shown (fig. 5). Glacial-
Figure 3:
adapted from (4), (2), and (5). The Agulhas Current is represented by ACby AR, Agulhas return current by ARC, Mozambique Current by MC, East Madagascar Current by EMC, Red Sea Intermediate Water by RSIW, Benguela Undercurrent by BU, and the North Brazil Current by NBC. CD154 17-17K shows the ‘typical’ upstream foraminifer assemblages of the
CD154 17-17KCBR
MD02-2588
The StoryForaminifer assemblages have been used in the past as a proxy for paleo-leakage (commonly known as the Agulhas Leakage Fauna, or ALF) (1). Normalizing the ALF to the upstream Agulhas Current fauna can provide increased accuracy in the assessment of the leakage, as it takes
the south by the migratory Subtropical Front (STF) (fig. 3), which moves
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Subtropical Front
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urre
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Subtropical Front
Interglacial (e.g. Holocene)
Glacial (e.g. LGM)
Figure 2:
G A T E W A Y SInitial Training Network
References
-minifera deep-sea sediments.” 11(1): 15-35.
Figure 5: The tropical-
and the subpolar-polar fauna (right).
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To show the upstream glacial-interglacial variability in the Agulhas Current foraminifer assemblages and the influence this has on the downstream
