Aquifer-eustasy as the main driver of short-term sea-level fluctuations during Cretaceous hothouse climate phases
- Author(s)
- Benjamin Sames, Michael Wagreich, Clinton P. Conrad, Shahid Iqbal
- Abstract
A review of short-term (<3 myr: c. 100 kyr to 2.4 myr) Cretaceous sea-level fluctuations of several tens of metres indicates recent fundamental progress in understanding the underlying mechanisms for eustasy, both in timing and in correlation. Cretaceous third- and fourth-order hothouse sea-level changes, the sequence-stratigraphic framework, are linked to Milankovitch-type climate cycles, especially the longer-period sequence-building bands of 405 kyr and 1.2 myr. In the absence of continental ice sheets during Cretaceous hothouse phases (e.g. Cenomanian–Turonian), growing evidence indicates groundwater-related sea-level cycles: (1) the existence of Milankovitch-type humid-arid climate oscillations, proven via intense humid weathering records during times of regression and sea-level lowstands; (2) missing or inverse relationships of sea-level and the marine δ18O archives, i.e. the lack of a pronounced positive excursion, cooling signal during sea-level lowstands; and (3) the anti-phase relationship of sea and lake levels, attesting to high groundwater levels and charged continental aquifers during sea-level lowstands. This substantiates the aquifer-eustasy hypothesis. Rates of aquifer-eustatic sea-level change remain hard to decipher; however, reconstructions range from a very conservative minimum estimate of 0.04 mm a−1 (longer time intervals) to 0.7 mm a−1 (shorter, probably asymmetric cycles). Remarkably, aquifer-eustasy is recognized as a significant component for the Anthropocene sea-level budget.
- Organisation(s)
- Department of Geology
- External organisation(s)
- Sam Noble Oklahoma Museum of Natural History, Quaid-i-Azam University, University of Oslo (UiO)
- Journal
- Geological Society Special Publications
- Volume
- 498
- Pages
- 9-38
- No. of pages
- 30
- DOI
- https://doi.org/10.1144/SP498-2019-105
- Publication date
- 2020
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 105304 Hydrology, 105204 Climatology, 105121 Sedimentology, 105306 Oceanography
- Keywords
- ASJC Scopus subject areas
- Water Science and Technology, Ocean Engineering, Geology
- Sustainable Development Goals
- SDG 14 - Life Below Water, SDG 13 - Climate Action
- Portal url
- https://ucris.univie.ac.at/portal/en/publications/aquifereustasy-as-the-main-driver-of-shortterm-sealevel-fluctuations-during-cretaceous-hothouse-climate-phases(ca496e20-ea0e-435f-a5cc-8093d309425f).html