Sedimentology and ichnology of a shallow-marine clastic system from the Silurian-Devonian Furada Formation of Asturias, Spain: Benthic response to event deposition and environmental disturbance
Date
2024-06-28
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
0000-0003-1647-4967
Type
Thesis
Degree Level
Masters
Abstract
The Furada Formation of Asturias, Spain, represents a clastic, wave-dominated shallow-marine unit deposited during the middle Silurian to the Early Devonian. This formation contains abundant evidence of event deposition and non-uniform distribution of bioturbation structures representing a benthic response to multiple stressors. The 170 m-thick succession was measured and described, and the ichnotaxa were recorded and associated with lithofacies. Most shallow-marine environments are characterized by periodic events of environmental disturbance, mainly by episodic deposition, which may be recorded by a change in both the degree of bioturbation and
ichnodiversity. The general depositional setting for this formation has been previously interpreted as a wave-dominated and storm-influenced shallow-marine environment. However,
sedimentologic features described in this study such as anomalous heterolithic units and fluid mud flow deposits suggest the influence of fluvial discharge, making it a more complex depositional setting. Body fossils are restricted to a single subfacies and include disarticulated and fragmented echinoderms, brachiopods and bryozoans. The trace-fossil assemblages of this formation reflect environmental stress factors introduced by fluvial input (e.g., sedimentation rate, hydrodynamic energy, substrate consolidation), resulting in reduced ichnodiversity and low abundance. The overall trace-fossil content of the Furada Formation is generally representative of the Cruziana Ichnofacies. Integration of sedimentologic and ichnologic datasets allows for a refined depositional interpretation of the formation and greater understanding of the environmental diversity of wave-dominated shallow marine clastic systems, including middle Paleozoic shallow-marine benthos and their responses to event sedimentation and environmental disturbance.
Description
Keywords
Shallow-marine, Sedimentology, Ichnology, Silurian, Devonian, Furada Formation, Cantabrian Zone
Citation
Degree
Master of Science (M.Sc.)
Department
Geological Sciences
Program
Geology