Palynological calibration of Devonian events at near-polar palaeolatitudes in the Falkland Islands, South Atlantic
Published:January 01, 2016
J. E. A. Marshall, 2016. "Palynological calibration of Devonian events at near-polar palaeolatitudes in the Falkland Islands, South Atlantic", Devonian Climate, Sea Level and Evolutionary Events, R. T. Becker, P. Königshof, C. E. Brett
Download citation file:
In the Devonian, the Falkland Islands were part of the high-latitude Cape Basin. West Falkland palynological assemblages are at a low thermal maturity level but also very low in diversity and dominated by simple spores with rare chitinozoans and acritarchs. The South Harbour Member contains rare verrucate and sculptured trilete spores, and is early Lochkovian. The Fish Creek Member palynofloras are late Lochkovian. The best correlative datum is the transgressive Fox Bay Formation where the palynological assemblage includes Ramochitina magnifica and is equivalent to the Sequence B transgression in Brazil (dated as late Pragian–earliest Emsian). The early Eifelian upper Fox Bay Formation spore assemblage is comparable to the Sequence C transgression in Brazil and the ?Choteč Event. The facies and position of the base Port Philomel Formation prasinophyte-rich black shale suggests the late Eifelian transgression (Kačák Event). Above this level is the inception of Geminospora lemurata (base Givetian). The upper Port Stanley Formation contains a late (but not latest) Famennian assemblage. Comparisons with both South Africa and South America indicate a number of correlative transgressive and regressive events that match to Euramerica. These correlations are at a continental scale and confirm eustatic control of these Devonian events.
Figures & Tables
Devonian Climate, Sea Level and Evolutionary Events
The geological and palaeontological records of climate change and evolutionary events reflect Earth’s widely fluctuating climate systems. Past climates hold the clues to understanding future developments. In this context, research on linked climate, biodiversity and sea-level fluctuations of the Devonian contributes to the general knowledge of deep-time climate dynamics. A fruitful co-operation between the International Geoscience Programme IGCP 596 and the International Subcommission on Devonian Stratigraphy (SDS) addressed the complex succession of climate-linked Devonian global events of varying magnitude. The primary goal of IGCP 596 was to assess mid-Palaeozoic climate changes and their impact on marine and terrestrial biodiversity using an interdisciplinary approach. The focus of SDS includes a revision of the eustatic sea-level curve and the integration of refined chrono- and biostratigraphy with modern chemo-, magneto-, cyclo-, event- and sequence stratigraphy. This enabled the much improved dating and correlation of abiotic perturbations, evolutionary changes, organism and ecosystem ranges. Results by 37 authors are presented in 14 chapters, which cover the entire Devonian.