Stable isotope paleoclimatology of the earliest Eocene using kimberlite-hosted mummified wood from the Canadian Subarctic
The recent discovery of well-preserved mummified wood buried within a subarctic kimberlite diamond mine prompted a paleoclimatic study of the early Eocene "hothouse" (ca. 53.3 Ma). At the time of kimberlite eruption, the Subarctic was warm and humid producing a temperate rainforest biome w...
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Copernicus Publications
2015
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Online Access: | https://doi.org/10.5194/bg-12-5899-2015 https://doaj.org/article/91397a46bfbb441d986ae3f007b56c43 |
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ftdoajarticles:oai:doaj.org/article:91397a46bfbb441d986ae3f007b56c43 2023-05-15T15:17:12+02:00 Stable isotope paleoclimatology of the earliest Eocene using kimberlite-hosted mummified wood from the Canadian Subarctic B. A. Hook J. Halfar Z. Gedalof J. Bollmann D. J. Schulze 2015-10-01T00:00:00Z https://doi.org/10.5194/bg-12-5899-2015 https://doaj.org/article/91397a46bfbb441d986ae3f007b56c43 EN eng Copernicus Publications http://www.biogeosciences.net/12/5899/2015/bg-12-5899-2015.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 1726-4170 1726-4189 doi:10.5194/bg-12-5899-2015 https://doaj.org/article/91397a46bfbb441d986ae3f007b56c43 Biogeosciences, Vol 12, Iss 20, Pp 5899-5914 (2015) Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 article 2015 ftdoajarticles https://doi.org/10.5194/bg-12-5899-2015 2022-12-31T14:27:20Z The recent discovery of well-preserved mummified wood buried within a subarctic kimberlite diamond mine prompted a paleoclimatic study of the early Eocene "hothouse" (ca. 53.3 Ma). At the time of kimberlite eruption, the Subarctic was warm and humid producing a temperate rainforest biome well north of the Arctic Circle. Previous studies have estimated that mean annual temperatures in this region were 4–20 °C in the early Eocene, using a variety of proxies including leaf margin analysis and stable isotopes (δ 13 C and δ 18 O) of fossil cellulose. Here, we examine stable isotopes of tree-ring cellulose at subannual- to annual-scale resolution, using the oldest viable cellulose found to date. We use mechanistic models and transfer functions to estimate earliest Eocene temperatures using mummified cellulose, which was well preserved in the kimberlite. Multiple samples of Piceoxylon wood within the kimberlite were crossdated by tree-ring width. Multiple proxies are used in combination to tease apart likely environmental factors influencing the tree physiology and growth in the unique extinct ecosystem of the Polar rainforest. Calculations of interannual variation in temperature over a multidecadal time-slice in the early Eocene are presented, with a mean annual temperature (MAT) estimate of 11.4 °C (1 σ = 1.8 °C) based on δ 18 O, which is 16 °C warmer than the current MAT of the area (−4.6 °C). Early Eocene atmospheric δ 13 C (δ 13 C atm ) estimates were −5.5 (±0.7) ‰. Isotopic discrimination (Δ) and leaf intercellular p CO 2 ratio ( c i / c a ) were similar to modern values (Δ = 18.7 ± 0.8 ‰; c i / c a = 0.63 ± 0.03 %), but intrinsic water use efficiency (Early Eocene iWUE = 211 ± 20 μmol mol −1 ) was over twice the level found in modern high-latitude trees. Dual-isotope spectral analysis suggests that multidecadal climate cycles somewhat similar to the modern Pacific Decadal Oscillation likely drove temperature and cloudiness trends on 20–30-year timescales, influencing photosynthetic productivity and tree growth ... Article in Journal/Newspaper Arctic Subarctic Directory of Open Access Journals: DOAJ Articles Arctic Pacific Biogeosciences 12 20 5899 5914 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
spellingShingle |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 B. A. Hook J. Halfar Z. Gedalof J. Bollmann D. J. Schulze Stable isotope paleoclimatology of the earliest Eocene using kimberlite-hosted mummified wood from the Canadian Subarctic |
topic_facet |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
description |
The recent discovery of well-preserved mummified wood buried within a subarctic kimberlite diamond mine prompted a paleoclimatic study of the early Eocene "hothouse" (ca. 53.3 Ma). At the time of kimberlite eruption, the Subarctic was warm and humid producing a temperate rainforest biome well north of the Arctic Circle. Previous studies have estimated that mean annual temperatures in this region were 4–20 °C in the early Eocene, using a variety of proxies including leaf margin analysis and stable isotopes (δ 13 C and δ 18 O) of fossil cellulose. Here, we examine stable isotopes of tree-ring cellulose at subannual- to annual-scale resolution, using the oldest viable cellulose found to date. We use mechanistic models and transfer functions to estimate earliest Eocene temperatures using mummified cellulose, which was well preserved in the kimberlite. Multiple samples of Piceoxylon wood within the kimberlite were crossdated by tree-ring width. Multiple proxies are used in combination to tease apart likely environmental factors influencing the tree physiology and growth in the unique extinct ecosystem of the Polar rainforest. Calculations of interannual variation in temperature over a multidecadal time-slice in the early Eocene are presented, with a mean annual temperature (MAT) estimate of 11.4 °C (1 σ = 1.8 °C) based on δ 18 O, which is 16 °C warmer than the current MAT of the area (−4.6 °C). Early Eocene atmospheric δ 13 C (δ 13 C atm ) estimates were −5.5 (±0.7) ‰. Isotopic discrimination (Δ) and leaf intercellular p CO 2 ratio ( c i / c a ) were similar to modern values (Δ = 18.7 ± 0.8 ‰; c i / c a = 0.63 ± 0.03 %), but intrinsic water use efficiency (Early Eocene iWUE = 211 ± 20 μmol mol −1 ) was over twice the level found in modern high-latitude trees. Dual-isotope spectral analysis suggests that multidecadal climate cycles somewhat similar to the modern Pacific Decadal Oscillation likely drove temperature and cloudiness trends on 20–30-year timescales, influencing photosynthetic productivity and tree growth ... |
format |
Article in Journal/Newspaper |
author |
B. A. Hook J. Halfar Z. Gedalof J. Bollmann D. J. Schulze |
author_facet |
B. A. Hook J. Halfar Z. Gedalof J. Bollmann D. J. Schulze |
author_sort |
B. A. Hook |
title |
Stable isotope paleoclimatology of the earliest Eocene using kimberlite-hosted mummified wood from the Canadian Subarctic |
title_short |
Stable isotope paleoclimatology of the earliest Eocene using kimberlite-hosted mummified wood from the Canadian Subarctic |
title_full |
Stable isotope paleoclimatology of the earliest Eocene using kimberlite-hosted mummified wood from the Canadian Subarctic |
title_fullStr |
Stable isotope paleoclimatology of the earliest Eocene using kimberlite-hosted mummified wood from the Canadian Subarctic |
title_full_unstemmed |
Stable isotope paleoclimatology of the earliest Eocene using kimberlite-hosted mummified wood from the Canadian Subarctic |
title_sort |
stable isotope paleoclimatology of the earliest eocene using kimberlite-hosted mummified wood from the canadian subarctic |
publisher |
Copernicus Publications |
publishDate |
2015 |
url |
https://doi.org/10.5194/bg-12-5899-2015 https://doaj.org/article/91397a46bfbb441d986ae3f007b56c43 |
geographic |
Arctic Pacific |
geographic_facet |
Arctic Pacific |
genre |
Arctic Subarctic |
genre_facet |
Arctic Subarctic |
op_source |
Biogeosciences, Vol 12, Iss 20, Pp 5899-5914 (2015) |
op_relation |
http://www.biogeosciences.net/12/5899/2015/bg-12-5899-2015.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 1726-4170 1726-4189 doi:10.5194/bg-12-5899-2015 https://doaj.org/article/91397a46bfbb441d986ae3f007b56c43 |
op_doi |
https://doi.org/10.5194/bg-12-5899-2015 |
container_title |
Biogeosciences |
container_volume |
12 |
container_issue |
20 |
container_start_page |
5899 |
op_container_end_page |
5914 |
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1766347471000174592 |