Carbon isotope (δ<sup>13</sup>C) excursions suggest times of major methane release during the last 14 kyr in Fram Strait, the deep-water gateway to the Arctic
We present results from a sediment core collected from a pockmark field on the Vestnesa Ridge (~ 80° N) in the eastern Fram Strait. This is the only deep-water gateway to the Arctic, and one of the northernmost marine gas hydrate provinces in the world. Eight <sup>14</sup>C AMS dates rev...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2015-04-01
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| Series: | Climate of the Past |
| Online Access: | http://www.clim-past.net/11/669/2015/cp-11-669-2015.pdf |
| _version_ | 1818022250027155456 |
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| author | C. Consolaro T. L. Rasmussen G. Panieri J. Mienert S. Bünz K. Sztybor |
| author_facet | C. Consolaro T. L. Rasmussen G. Panieri J. Mienert S. Bünz K. Sztybor |
| author_sort | C. Consolaro |
| collection | DOAJ |
| description | We present results from a sediment core collected from a pockmark field on
the Vestnesa Ridge (~ 80° N) in the eastern Fram Strait.
This is the only deep-water gateway to the Arctic, and one of the
northernmost marine gas hydrate provinces in the world. Eight <sup>14</sup>C AMS
dates reveal a detailed chronology for the last 14 ka BP. The δ
<sup>13</sup>C record measured on the benthonic foraminiferal species
<i>Cassidulina neoteretis</i> shows two distinct intervals with negative values termed carbon isotope
excursion (CIE I and CIE II, respectively). The values were as low as
−4.37‰ in CIE I, correlating with the
Bølling–Allerød interstadials, and as low as −3.41‰
in CIE II, correlating with the early Holocene. In the Bølling–Allerød
interstadials, the planktonic foraminifera also show negative values,
probably indicating secondary methane-derived authigenic precipitation
affecting the foraminiferal shells. After a cleaning procedure designed to
remove authigenic carbonate coatings on benthonic foraminiferal tests from
this event, the <sup>13</sup>C values are still negative (as low as
−2.75‰). The CIE I and CIE II occurred during periods
of ocean warming, sea-level rise and increased concentrations of methane
(CH<sub>4</sub>) in the atmosphere. CIEs with similar timing have been reported
from other areas in the North Atlantic, suggesting a regional event. The
trigger mechanisms for such regional events remain to be determined. We
speculate that sea-level rise and seabed loading due to high sediment supply
in combination with increased seismic activity as a result of rapid
deglaciation may have triggered the escape of significant amounts of methane
to the seafloor and the water column above. |
| first_indexed | 2024-04-14T08:28:47Z |
| format | Article |
| id | doaj.art-4558dda9d3c14cfabae5a0dd3e079dfe |
| institution | Directory Open Access Journal |
| issn | 1814-9324 1814-9332 |
| language | English |
| last_indexed | 2024-04-14T08:28:47Z |
| publishDate | 2015-04-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Climate of the Past |
| spelling | doaj.art-4558dda9d3c14cfabae5a0dd3e079dfe2022-12-22T02:03:58ZengCopernicus PublicationsClimate of the Past1814-93241814-93322015-04-0111466968510.5194/cp-11-669-2015Carbon isotope (δ<sup>13</sup>C) excursions suggest times of major methane release during the last 14 kyr in Fram Strait, the deep-water gateway to the ArcticC. Consolaro0T. L. Rasmussen1G. Panieri2J. Mienert3S. Bünz4K. Sztybor5CAGE – Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geology, UiT the Arctic University of Norway, Dramsveien 201, 9037 Tromsø, NorwayCAGE – Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geology, UiT the Arctic University of Norway, Dramsveien 201, 9037 Tromsø, NorwayCAGE – Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geology, UiT the Arctic University of Norway, Dramsveien 201, 9037 Tromsø, NorwayCAGE – Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geology, UiT the Arctic University of Norway, Dramsveien 201, 9037 Tromsø, NorwayCAGE – Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geology, UiT the Arctic University of Norway, Dramsveien 201, 9037 Tromsø, NorwayCAGE – Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geology, UiT the Arctic University of Norway, Dramsveien 201, 9037 Tromsø, NorwayWe present results from a sediment core collected from a pockmark field on the Vestnesa Ridge (~ 80° N) in the eastern Fram Strait. This is the only deep-water gateway to the Arctic, and one of the northernmost marine gas hydrate provinces in the world. Eight <sup>14</sup>C AMS dates reveal a detailed chronology for the last 14 ka BP. The δ <sup>13</sup>C record measured on the benthonic foraminiferal species <i>Cassidulina neoteretis</i> shows two distinct intervals with negative values termed carbon isotope excursion (CIE I and CIE II, respectively). The values were as low as −4.37‰ in CIE I, correlating with the Bølling–Allerød interstadials, and as low as −3.41‰ in CIE II, correlating with the early Holocene. In the Bølling–Allerød interstadials, the planktonic foraminifera also show negative values, probably indicating secondary methane-derived authigenic precipitation affecting the foraminiferal shells. After a cleaning procedure designed to remove authigenic carbonate coatings on benthonic foraminiferal tests from this event, the <sup>13</sup>C values are still negative (as low as −2.75‰). The CIE I and CIE II occurred during periods of ocean warming, sea-level rise and increased concentrations of methane (CH<sub>4</sub>) in the atmosphere. CIEs with similar timing have been reported from other areas in the North Atlantic, suggesting a regional event. The trigger mechanisms for such regional events remain to be determined. We speculate that sea-level rise and seabed loading due to high sediment supply in combination with increased seismic activity as a result of rapid deglaciation may have triggered the escape of significant amounts of methane to the seafloor and the water column above.http://www.clim-past.net/11/669/2015/cp-11-669-2015.pdf |
| spellingShingle | C. Consolaro T. L. Rasmussen G. Panieri J. Mienert S. Bünz K. Sztybor Carbon isotope (δ<sup>13</sup>C) excursions suggest times of major methane release during the last 14 kyr in Fram Strait, the deep-water gateway to the Arctic Climate of the Past |
| title | Carbon isotope (δ<sup>13</sup>C) excursions suggest times of major methane release during the last 14 kyr in Fram Strait, the deep-water gateway to the Arctic |
| title_full | Carbon isotope (δ<sup>13</sup>C) excursions suggest times of major methane release during the last 14 kyr in Fram Strait, the deep-water gateway to the Arctic |
| title_fullStr | Carbon isotope (δ<sup>13</sup>C) excursions suggest times of major methane release during the last 14 kyr in Fram Strait, the deep-water gateway to the Arctic |
| title_full_unstemmed | Carbon isotope (δ<sup>13</sup>C) excursions suggest times of major methane release during the last 14 kyr in Fram Strait, the deep-water gateway to the Arctic |
| title_short | Carbon isotope (δ<sup>13</sup>C) excursions suggest times of major methane release during the last 14 kyr in Fram Strait, the deep-water gateway to the Arctic |
| title_sort | carbon isotope δ sup 13 sup c excursions suggest times of major methane release during the last 14 kyr in fram strait the deep water gateway to the arctic |
| url | http://www.clim-past.net/11/669/2015/cp-11-669-2015.pdf |
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