(Table S1) Boron isotope and trace element data and reconstructed carbonate system parameters, ODP Holes 122-761B and 154-926A
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| Formato: | Dataset Open Access |
| Lenguaje: | en |
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PANGAEA
2012
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| _version_ | 1867171816216199168 |
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| author | Foster, Gavin L Lear, Caroline H Rae, James W B |
| author_facet | Foster, Gavin L Lear, Caroline H Rae, James W B |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | The middle Miocene Climatic Optimum (17-15 Ma; MCO) is a period of global warmth and relatively high CO2 and is thought to be associated with a significant retreat of the Antarctic Ice Sheet (AIS). We present here a new planktic foraminiferal d11B record from 16.6 to 11.8 Ma from two deep ocean sites currently in equilibrium with the atmosphere with respect to CO2. These new data demonstrate that the evolution of global climate during the middle Miocene (as reflected by changes in the cyrosphere) was well correlated to variations in the concentration of atmospheric CO2. What is more, within our sampling resolution (~1 sample per 300 kyr) there is no evidence of hysteresis in the response of ice volume to CO2 forcing during the middle Miocene, contrary to what is understood about the Antarctic Ice Sheet from ice sheet modelling studies. In agreement with previous data, we show that absolute levels of CO2 during the MCO were relatively modest (350-400 ppm) and levels either side of the MCO are similar or lower than the pre-industrial (200-260 ppm). These new data imply the presence of either a very dynamic AIS at relatively low CO2 during the middle Miocene or the advance and retreat of significant northern hemisphere ice. Recent drilling on the Antarctic margin and shore based studies indicate significant retreat and advance beyond the modern limits of the AIS did occur during the middle Miocene, but the complete loss of the AIS was unlikely. Consequently, it seems that ice volume and climate variations during the middle Miocene probably involved a more dynamic AIS than the modern but also some component of land-based ice in the northern hemisphere. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_815855 |
| institution | PANGAEA |
| language | en |
| publishDate | 2012 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | (Table S1) Boron isotope and trace element data and reconstructed carbonate system parameters, ODP Holes 122-761B and 154-926A Foster, Gavin L Lear, Caroline H Rae, James W B 122-761B; 154-926A; AGE; Boron; Calculated; Carbonate ion; Carbonate ion, standard deviation; Carbon dioxide, partial pressure; Carbon dioxide, partial pressure, standard deviation; Cibicidoides mundulus, Magnesium/Calcium ratio; Cibicidoides wuellerstorfi, Magnesium/Calcium ratio; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Error; Event label; Globigerinoides sacculifer, Magnesium/Calcium ratio; ICP-MS, Thermo Fisher Scientific, Element 2; Joides Resolution; Leg122; Leg154; MC-ICP-MS, Thermo Fisher Scientific NEPTUN; North Atlantic Ocean; Ocean Drilling Program; ODP; pH, total scale; Sample code/label; South Indian Ridge, South Indian Ocean; Species; Standard error; Temperature, calculated; δ11B; δ11B, standard deviation The middle Miocene Climatic Optimum (17-15 Ma; MCO) is a period of global warmth and relatively high CO2 and is thought to be associated with a significant retreat of the Antarctic Ice Sheet (AIS). We present here a new planktic foraminiferal d11B record from 16.6 to 11.8 Ma from two deep ocean sites currently in equilibrium with the atmosphere with respect to CO2. These new data demonstrate that the evolution of global climate during the middle Miocene (as reflected by changes in the cyrosphere) was well correlated to variations in the concentration of atmospheric CO2. What is more, within our sampling resolution (~1 sample per 300 kyr) there is no evidence of hysteresis in the response of ice volume to CO2 forcing during the middle Miocene, contrary to what is understood about the Antarctic Ice Sheet from ice sheet modelling studies. In agreement with previous data, we show that absolute levels of CO2 during the MCO were relatively modest (350-400 ppm) and levels either side of the MCO are similar or lower than the pre-industrial (200-260 ppm). These new data imply the presence of either a very dynamic AIS at relatively low CO2 during the middle Miocene or the advance and retreat of significant northern hemisphere ice. Recent drilling on the Antarctic margin and shore based studies indicate significant retreat and advance beyond the modern limits of the AIS did occur during the middle Miocene, but the complete loss of the AIS was unlikely. Consequently, it seems that ice volume and climate variations during the middle Miocene probably involved a more dynamic AIS than the modern but also some component of land-based ice in the northern hemisphere. |
| title | (Table S1) Boron isotope and trace element data and reconstructed carbonate system parameters, ODP Holes 122-761B and 154-926A |
| topic | 122-761B; 154-926A; AGE; Boron; Calculated; Carbonate ion; Carbonate ion, standard deviation; Carbon dioxide, partial pressure; Carbon dioxide, partial pressure, standard deviation; Cibicidoides mundulus, Magnesium/Calcium ratio; Cibicidoides wuellerstorfi, Magnesium/Calcium ratio; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Error; Event label; Globigerinoides sacculifer, Magnesium/Calcium ratio; ICP-MS, Thermo Fisher Scientific, Element 2; Joides Resolution; Leg122; Leg154; MC-ICP-MS, Thermo Fisher Scientific NEPTUN; North Atlantic Ocean; Ocean Drilling Program; ODP; pH, total scale; Sample code/label; South Indian Ridge, South Indian Ocean; Species; Standard error; Temperature, calculated; δ11B; δ11B, standard deviation |
| url | https://doi.org/10.1594/PANGAEA.815855 |