A high-resolution record of early Paleozoic climate
The spatial coverage and temporal resolution of the Early Paleozoic paleoclimate record are limited, primarily due to the paucity of well-preserved skeletal material commonly used for oxygen-isotope paleothermometry. Bulk-rock δ¹⁸O datasets can provide broader coverage and higher resolution, but are...
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| Format: | Article |
| Language: | English |
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Proceedings of the National Academy of Sciences
2021
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| Online Access: | https://hdl.handle.net/1721.1/131282 |
| _version_ | 1826209169377591296 |
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| author | Goldberg, Samuel L. Present, Theodore M. Finnegan, Seth Bergmann, Kristin |
| author2 | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences |
| author_facet | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Goldberg, Samuel L. Present, Theodore M. Finnegan, Seth Bergmann, Kristin |
| author_sort | Goldberg, Samuel L. |
| collection | MIT |
| description | The spatial coverage and temporal resolution of the Early Paleozoic paleoclimate record are limited, primarily due to the paucity of well-preserved skeletal material commonly used for oxygen-isotope paleothermometry. Bulk-rock δ¹⁸O datasets can provide broader coverage and higher resolution, but are prone to burial alteration. We assess the diagenetic character of two thick Cambro-Ordovician carbonate platforms with minimal to moderate burial by pairing clumped and bulk isotope analyses of micritic carbonates. Despite resetting of the clumped-isotope thermometer at both sites, our samples indicate relatively little change to their bulk δ¹⁸O due to low fluid exchange. Consequently, both sequences preserve temporal trends in δ¹⁸O. Motivated by this result, we compile a global suite of bulk rock δ¹⁸O data, stacking overlapping regional records to minimize diagenetic influences on overall trends. We find good agreement of bulk rock δ¹⁸O with brachiopod and conodont δ¹⁸O trends through time. Given evidence that the δ¹⁸O value of seawater has not evolved substantially through the Phanerozoic, we interpret this record as primarily reflecting changes in tropical, nearshore seawater temperatures and only moderately modified by diagenesis. Focusing on the samples with the most enriched, and thus likely least-altered, δ¹⁸O values, we reconstruct Late Cambrian warming, Early Ordovician extreme warmth, and cooling around the Early-Middle Ordovician boundary. Our record is consistent with models linking the Great Ordovician Biodiversification Event to cooling of previously very warm tropical oceans. In addition, our high-temporal-resolution record suggests previously unresolved transient warming and climate instability potentially associated with Late Ordovician tectonic events. |
| first_indexed | 2024-09-23T14:18:18Z |
| format | Article |
| id | mit-1721.1/131282 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T14:18:18Z |
| publishDate | 2021 |
| publisher | Proceedings of the National Academy of Sciences |
| record_format | dspace |
| spelling | mit-1721.1/1312822022-09-29T08:34:30Z A high-resolution record of early Paleozoic climate Goldberg, Samuel L. Present, Theodore M. Finnegan, Seth Bergmann, Kristin Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences The spatial coverage and temporal resolution of the Early Paleozoic paleoclimate record are limited, primarily due to the paucity of well-preserved skeletal material commonly used for oxygen-isotope paleothermometry. Bulk-rock δ¹⁸O datasets can provide broader coverage and higher resolution, but are prone to burial alteration. We assess the diagenetic character of two thick Cambro-Ordovician carbonate platforms with minimal to moderate burial by pairing clumped and bulk isotope analyses of micritic carbonates. Despite resetting of the clumped-isotope thermometer at both sites, our samples indicate relatively little change to their bulk δ¹⁸O due to low fluid exchange. Consequently, both sequences preserve temporal trends in δ¹⁸O. Motivated by this result, we compile a global suite of bulk rock δ¹⁸O data, stacking overlapping regional records to minimize diagenetic influences on overall trends. We find good agreement of bulk rock δ¹⁸O with brachiopod and conodont δ¹⁸O trends through time. Given evidence that the δ¹⁸O value of seawater has not evolved substantially through the Phanerozoic, we interpret this record as primarily reflecting changes in tropical, nearshore seawater temperatures and only moderately modified by diagenesis. Focusing on the samples with the most enriched, and thus likely least-altered, δ¹⁸O values, we reconstruct Late Cambrian warming, Early Ordovician extreme warmth, and cooling around the Early-Middle Ordovician boundary. Our record is consistent with models linking the Great Ordovician Biodiversification Event to cooling of previously very warm tropical oceans. In addition, our high-temporal-resolution record suggests previously unresolved transient warming and climate instability potentially associated with Late Ordovician tectonic events. 2021-09-16T19:26:10Z 2021-09-16T19:26:10Z 2021-02 2020-07 2021-09-13T18:29:27Z Article http://purl.org/eprint/type/JournalArticle 0027-8424 1091-6490 https://hdl.handle.net/1721.1/131282 Goldberg, Samuel L. et al. "A high-resolution record of early Paleozoic climate." Proceedings of the National Academy of Sciences 118, 6 (February 2021): e2013083118. en http://dx.doi.org/10.1073/pnas.2013083118 Proceedings of the National Academy of Sciences Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf Proceedings of the National Academy of Sciences PNAS |
| spellingShingle | Goldberg, Samuel L. Present, Theodore M. Finnegan, Seth Bergmann, Kristin A high-resolution record of early Paleozoic climate |
| title | A high-resolution record of early Paleozoic climate |
| title_full | A high-resolution record of early Paleozoic climate |
| title_fullStr | A high-resolution record of early Paleozoic climate |
| title_full_unstemmed | A high-resolution record of early Paleozoic climate |
| title_short | A high-resolution record of early Paleozoic climate |
| title_sort | high resolution record of early paleozoic climate |
| url | https://hdl.handle.net/1721.1/131282 |
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