Mid-Cretaceous pCO₂, carbon-cycling and the rise of the flowering plants
The mid-Cretaceous (Aptian–Cenomanian) climate was characterised by steadily increasing temperatures likely driven by high atmospheric CO2. The climate system was dynamic: throughout this interval there were several dramatic carbon cycle perturbations (of 1–2 Myrs duration) due to initiation of mari...
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ftucl:oai:eprints.ucl.ac.uk.OAI2:1456312 2023-12-24T10:17:14+01:00 Mid-Cretaceous pCO₂, carbon-cycling and the rise of the flowering plants Fay, CA Robinson, SA McElwain, JE Bown, P 2014-11-28 text https://discovery.ucl.ac.uk/id/eprint/1456312/1/CORINNE%20ALEXANDRA%20FAY%202014%20PhD%20thesis%20COMPLETE.pdf https://discovery.ucl.ac.uk/id/eprint/1456312/ eng eng UCL (University College London) https://discovery.ucl.ac.uk/id/eprint/1456312/1/CORINNE%20ALEXANDRA%20FAY%202014%20PhD%20thesis%20COMPLETE.pdf https://discovery.ucl.ac.uk/id/eprint/1456312/ open Doctoral thesis, UCL (University College London). angiosperm Cretaceous carbon dioxide palaeoclimate Thesis Doctoral 2014 ftucl 2023-11-27T13:07:35Z The mid-Cretaceous (Aptian–Cenomanian) climate was characterised by steadily increasing temperatures likely driven by high atmospheric CO2. The climate system was dynamic: throughout this interval there were several dramatic carbon cycle perturbations (of 1–2 Myrs duration) due to initiation of marine anoxia (OAEs) resulting in burial of organic carbon. However, pCO2 values and trends are generally poorly constrained for much of this time interval. During the mid-Cretaceous, angiosperms (flowering plants) underwent a rapid poleward diversification and radiation; by the Cenomanian they comprised around 70% of floras. However, hypotheses detailing the competitive replacement of incumbent floras by advantageous angiosperm adaptations do not fully explain the timing and nature of early angiosperm evolution. This thesis provides a record of Albian–Cenomanian carbon cycling and explores the role of climate change and pCO2 decline (CO2 starvation hypothesis) as forcing factors on angiosperm radiation. This is achieved using fossil material from the Nuussuaq Peninsula, West Greenland. Carbon isotope stratigraphy constrains the stratigraphic age (Middle Albian-Cenomanian) and identifies two intervals of carbon cycle disturbance. Macerated leaf cuticle and palynological studies reveal detailed floral assemblages (in which angiosperms, including Eudicots, were poorly represented but present throughout) and unprecedented ecological information. New pCO2 estimates for the Middle Albian are generated from stomatal density measurements, which, integrated with other similar datasets, suggest average pCO2 in the Aptian-Early Cenomanian of 575 ppm with a decline of ~150 ppm in the Middle Albian. The subsequent rise in pCO2 through to the Late Albian coincides with a 30 % increase in angiosperm abundance and increased global temperatures; strongly suggesting the role of climate on angiosperm radiation. However, comparisons of vein density, stomatal conductance, stomatal density and pore length between fossil and extant angiosperms ... Doctoral or Postdoctoral Thesis Greenland Nuussuaq University College London: UCL Discovery Greenland Nuussuaq ENVELOPE(-51.918,-51.918,66.626,66.626) |
institution |
Open Polar |
collection |
University College London: UCL Discovery |
op_collection_id |
ftucl |
language |
English |
topic |
angiosperm Cretaceous carbon dioxide palaeoclimate |
spellingShingle |
angiosperm Cretaceous carbon dioxide palaeoclimate Fay, CA Mid-Cretaceous pCO₂, carbon-cycling and the rise of the flowering plants |
topic_facet |
angiosperm Cretaceous carbon dioxide palaeoclimate |
description |
The mid-Cretaceous (Aptian–Cenomanian) climate was characterised by steadily increasing temperatures likely driven by high atmospheric CO2. The climate system was dynamic: throughout this interval there were several dramatic carbon cycle perturbations (of 1–2 Myrs duration) due to initiation of marine anoxia (OAEs) resulting in burial of organic carbon. However, pCO2 values and trends are generally poorly constrained for much of this time interval. During the mid-Cretaceous, angiosperms (flowering plants) underwent a rapid poleward diversification and radiation; by the Cenomanian they comprised around 70% of floras. However, hypotheses detailing the competitive replacement of incumbent floras by advantageous angiosperm adaptations do not fully explain the timing and nature of early angiosperm evolution. This thesis provides a record of Albian–Cenomanian carbon cycling and explores the role of climate change and pCO2 decline (CO2 starvation hypothesis) as forcing factors on angiosperm radiation. This is achieved using fossil material from the Nuussuaq Peninsula, West Greenland. Carbon isotope stratigraphy constrains the stratigraphic age (Middle Albian-Cenomanian) and identifies two intervals of carbon cycle disturbance. Macerated leaf cuticle and palynological studies reveal detailed floral assemblages (in which angiosperms, including Eudicots, were poorly represented but present throughout) and unprecedented ecological information. New pCO2 estimates for the Middle Albian are generated from stomatal density measurements, which, integrated with other similar datasets, suggest average pCO2 in the Aptian-Early Cenomanian of 575 ppm with a decline of ~150 ppm in the Middle Albian. The subsequent rise in pCO2 through to the Late Albian coincides with a 30 % increase in angiosperm abundance and increased global temperatures; strongly suggesting the role of climate on angiosperm radiation. However, comparisons of vein density, stomatal conductance, stomatal density and pore length between fossil and extant angiosperms ... |
author2 |
Robinson, SA McElwain, JE Bown, P |
format |
Doctoral or Postdoctoral Thesis |
author |
Fay, CA |
author_facet |
Fay, CA |
author_sort |
Fay, CA |
title |
Mid-Cretaceous pCO₂, carbon-cycling and the rise of the flowering plants |
title_short |
Mid-Cretaceous pCO₂, carbon-cycling and the rise of the flowering plants |
title_full |
Mid-Cretaceous pCO₂, carbon-cycling and the rise of the flowering plants |
title_fullStr |
Mid-Cretaceous pCO₂, carbon-cycling and the rise of the flowering plants |
title_full_unstemmed |
Mid-Cretaceous pCO₂, carbon-cycling and the rise of the flowering plants |
title_sort |
mid-cretaceous pco₂, carbon-cycling and the rise of the flowering plants |
publisher |
UCL (University College London) |
publishDate |
2014 |
url |
https://discovery.ucl.ac.uk/id/eprint/1456312/1/CORINNE%20ALEXANDRA%20FAY%202014%20PhD%20thesis%20COMPLETE.pdf https://discovery.ucl.ac.uk/id/eprint/1456312/ |
long_lat |
ENVELOPE(-51.918,-51.918,66.626,66.626) |
geographic |
Greenland Nuussuaq |
geographic_facet |
Greenland Nuussuaq |
genre |
Greenland Nuussuaq |
genre_facet |
Greenland Nuussuaq |
op_source |
Doctoral thesis, UCL (University College London). |
op_relation |
https://discovery.ucl.ac.uk/id/eprint/1456312/1/CORINNE%20ALEXANDRA%20FAY%202014%20PhD%20thesis%20COMPLETE.pdf https://discovery.ucl.ac.uk/id/eprint/1456312/ |
op_rights |
open |
_version_ |
1786205208312807424 |