Coastal sediments from the Algarve

Low-latitude climate archive for the Aptian-Albian

authored by: Ulrich Heimhofer, Thierry Adatte, Peter A. Hochuli, Stefan Burla, Helmut Weissert
Abstract: The Late Aptian to Early Albian transition has previously been identified as a possible example of substantial climate cooling within the mid-Cretaceous greenhouse period. To study the response of continental weathering and terrestrial vegetation to this cooling episode at low- to mid-latitudes, marine nearshore deposits from the Algarve Basin (SW Portugal) have been investigated with a combined approach including palynology, clay mineralogy and bulk-rock geochemistry. In the Lower Aptian part of the succession, quartz-rich sandstone facies is accompanied by high abundances of early diagenetic kaolinite, which is interpreted to reflect episodes of enhanced humidity and high meteoric flow-through. In contrast, the Late Aptian to Early Albian deposits are characterized by high abundances of detrital clay minerals (mica and chlorite) indicating the dominance of physical weathering processes in the source area, most probably related to low precipitation rates in conjunction with tectonically enhanced erosion. Palynological data show a strong dominance of Classopollis pollen associated with low pteridophyte spore abundances, suggesting warm semi-arid to arid palaeoenvironments. Changes in sedimentation patterns from varicoloured lagoonal marls to thick-bedded shallow-water carbonates are neither expressed in the spore-pollen assemblages nor in the distributions of clay minerals which both remain essentially stable throughout the Late Aptian to Early Albian. These relatively stable patterns are in contrast with various lines of evidence, predominantly from high-latitude areas, that suggest a significant cooling during this time interval. Our study demonstrates that terrestrial environments of low- to mid-latitude regions were not significantly affected by the Late Aptian - Early Albian "cold snap".
External Organisation(s): Ruhr-Universität Bochum
Universite de Neuchatel
Universität Zürich (UZH)
ETH Zurich
Type: Article
Journal: International Journal of Earth Sciences
Volume: 97
Pages: 785-797
No. of pages: 13
ISSN: 1437-3254
Publication date: 07.2008
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: General Earth and Planetary Sciences
Sustainable Development Goals: SDG 13 - Climate Action, SDG 14 - Life Below Water
Electronic version(s): https://doi.org/10.1007/s00531-007-0186-y (Access: Unknown)