Ghobadi Pour, Mansoureh, Popov, Leonid and Cherns, Lesley ![]() ![]() |
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Abstract
Review of current progress in Mid to Late Ordovician astrochronological studies exposes some important issues related to cyclostratigraphical studies, including the completeness and correlation of successions, and the connection between inferred astronomical cycles and geological events recorded in the sedimentary record. While bulk, low-field, mass specific magnetic susceptibility methods are widely applied in studies of high resolution cyclostratigraphy, they require close support from sequence stratigraphy and biostratigraphy, and should be linked back to outcrop patterns. Otherwise they risk distortion in the calibration against geological time, through lack of anchoring to well-defined biostratigraphical horizons and unrecognised condensed intervals and larger hiatuses. A significant limitation currently is that few high-resolution radio-isotope ages are linked to well-defined biostratigraphical boundaries. Nevertheless, fourth order sedimentary sequences linked to 405 kyr orbital eccentricity cycles, and longer orbital cyclicity impressed in third-order sequences, represent good grounds for development of a reliable astrochronological scale. The astrochronologically calibrated sequence-stratigraphical record documented from high latitude Gondwana shows significant impact from orbital forcing on the Mid to Late Ordovician global climate.
Item Type: | Article |
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Date Type: | Publication |
Status: | Published |
Schools: | Earth and Environmental Sciences |
Subjects: | Q Science > QE Geology |
Publisher: | Journal of Climate Change Research |
Date of First Compliant Deposit: | 4 March 2021 |
Date of Acceptance: | 22 November 2020 |
Last Modified: | 04 May 2023 23:36 |
URI: | https://orca.cardiff.ac.uk/id/eprint/139168 |
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