Mid- latitude alluvial and hydroclimatic changes during the Paleocene–Eocene Thermal Maximum as recorded in the Tremp- Graus Basin, Spain
(2022) In Sedimentary Geology 435.- Abstract
A short episode (~170 kyr) of extremely high global temperatures that occurred ~56 Ma, known as the Paleocene–Eocene Thermal Maximum, is widely considered an ancient analogue of the ongoing anthropogenic warming. This ancient hyperthermal event consisted of three phases, onset, core and recovery, which are respectively represented in the mid-latitude south Pyrenean Tremp-Graus Basin by three successive terrestrial units, the Claret Conglomerate, the Yellowish Soils and the Gypsum-rich Unit, each of them recording a different sedimentary response to evolving climatic and hydrological regimes. The Claret Conglomerate is mainly made up of calcareous conglomerates and is acknowledged to record an abrupt hydrological change during the onset... (More)
A short episode (~170 kyr) of extremely high global temperatures that occurred ~56 Ma, known as the Paleocene–Eocene Thermal Maximum, is widely considered an ancient analogue of the ongoing anthropogenic warming. This ancient hyperthermal event consisted of three phases, onset, core and recovery, which are respectively represented in the mid-latitude south Pyrenean Tremp-Graus Basin by three successive terrestrial units, the Claret Conglomerate, the Yellowish Soils and the Gypsum-rich Unit, each of them recording a different sedimentary response to evolving climatic and hydrological regimes. The Claret Conglomerate is mainly made up of calcareous conglomerates and is acknowledged to record an abrupt hydrological change during the onset phase. This unit most likely formed in an alluvial megafan, an interpretation here reinforced with new architectural information and by comparison with naturally occurring small-scale fan-like accumulations. Assuming the similarity between the onset of the Paleocene–Eocene Thermal Maximum and the anthropogenic warming, recent hydrological and meteorological data from mid-latitude Spain were compiled for comparison purposes. This comparison concurs with published modelling results about hydroclimate changes in the Pyrenees during the hyperthermal event, postulating an enhancement of seasonal contrast with augmented frequency and intensity of floods but no significant change in total rain. Furthermore, the comparison suggests that the Claret Conglomerate accumulated during extreme rainfall episodes that mainly occurred in autumn. The Yellowish Soils are mostly composed of silty marls with ubiquitous small-sized carbonate nodules and intercalated calcarenites. The marls were deposited in floodplains and the calcarenites in point bars and crevasse splays of meandering rivers. The scarcity of conglomerates entails a near absence of strong currents, and the carbonate nodules perennial or seasonal arid conditions. These nodules occur within cumulate palaeosols, the development of which required regular sedimentary increments during inundations on the floodplains. Sedimentation rates of siliciclastic material on the floodplains increased significantly during the core of the hyperthermal event, as well as at river outlets in coastal settings, which shows that erosion was accelerated and rules out the occurrence of protective, dense vegetation. Combined, these characteristics suggest persistent very dry summers, but a smooth wet season without intense precipitation events. Lastly, the profusion of gypsum in the youngest unit is clear proof of an arid climate during the recovery of the hyperthermal event. In essence, the studied deposits provide a unique window into the sequence of hydroclimatic change during the rise, peak and decline of an ancient global warming event in a mid-latitude terrestrial setting, against which ongoing climate-change data and future projections can be compared.
(Less)
- author
- Payros, Aitor ; Pujalte, Victoria no and Schmitz, Birger LU
- organization
- publishing date
- 2022
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Alluvial architecture, Claret Conglomerate, Palaeoclimate, Palaeosols, PETM, Yellowish Soils
- in
- Sedimentary Geology
- volume
- 435
- article number
- 106155
- publisher
- Elsevier
- external identifiers
-
- scopus:85129592107
- ISSN
- 0037-0738
- DOI
- 10.1016/j.sedgeo.2022.106155
- language
- English
- LU publication?
- yes
- id
- 40a378dd-3592-4768-9e6c-b68a97d10481
- date added to LUP
- 2022-07-06 11:02:51
- date last changed
- 2022-07-06 11:02:51
@article{40a378dd-3592-4768-9e6c-b68a97d10481,
abstract = {{<p>A short episode (~170 kyr) of extremely high global temperatures that occurred ~56 Ma, known as the Paleocene–Eocene Thermal Maximum, is widely considered an ancient analogue of the ongoing anthropogenic warming. This ancient hyperthermal event consisted of three phases, onset, core and recovery, which are respectively represented in the mid-latitude south Pyrenean Tremp-Graus Basin by three successive terrestrial units, the Claret Conglomerate, the Yellowish Soils and the Gypsum-rich Unit, each of them recording a different sedimentary response to evolving climatic and hydrological regimes. The Claret Conglomerate is mainly made up of calcareous conglomerates and is acknowledged to record an abrupt hydrological change during the onset phase. This unit most likely formed in an alluvial megafan, an interpretation here reinforced with new architectural information and by comparison with naturally occurring small-scale fan-like accumulations. Assuming the similarity between the onset of the Paleocene–Eocene Thermal Maximum and the anthropogenic warming, recent hydrological and meteorological data from mid-latitude Spain were compiled for comparison purposes. This comparison concurs with published modelling results about hydroclimate changes in the Pyrenees during the hyperthermal event, postulating an enhancement of seasonal contrast with augmented frequency and intensity of floods but no significant change in total rain. Furthermore, the comparison suggests that the Claret Conglomerate accumulated during extreme rainfall episodes that mainly occurred in autumn. The Yellowish Soils are mostly composed of silty marls with ubiquitous small-sized carbonate nodules and intercalated calcarenites. The marls were deposited in floodplains and the calcarenites in point bars and crevasse splays of meandering rivers. The scarcity of conglomerates entails a near absence of strong currents, and the carbonate nodules perennial or seasonal arid conditions. These nodules occur within cumulate palaeosols, the development of which required regular sedimentary increments during inundations on the floodplains. Sedimentation rates of siliciclastic material on the floodplains increased significantly during the core of the hyperthermal event, as well as at river outlets in coastal settings, which shows that erosion was accelerated and rules out the occurrence of protective, dense vegetation. Combined, these characteristics suggest persistent very dry summers, but a smooth wet season without intense precipitation events. Lastly, the profusion of gypsum in the youngest unit is clear proof of an arid climate during the recovery of the hyperthermal event. In essence, the studied deposits provide a unique window into the sequence of hydroclimatic change during the rise, peak and decline of an ancient global warming event in a mid-latitude terrestrial setting, against which ongoing climate-change data and future projections can be compared.</p>}},
author = {{Payros, Aitor and Pujalte, Victoria no and Schmitz, Birger}},
issn = {{0037-0738}},
keywords = {{Alluvial architecture; Claret Conglomerate; Palaeoclimate; Palaeosols; PETM; Yellowish Soils}},
language = {{eng}},
publisher = {{Elsevier}},
series = {{Sedimentary Geology}},
title = {{Mid- latitude alluvial and hydroclimatic changes during the Paleocene–Eocene Thermal Maximum as recorded in the Tremp- Graus Basin, Spain}},
url = {{http://dx.doi.org/10.1016/j.sedgeo.2022.106155}},
doi = {{10.1016/j.sedgeo.2022.106155}},
volume = {{435}},
year = {{2022}},
}