Skip to Main Content
Skip Nav Destination
GEOREF RECORD

River reversals into karst springs; a model for cave enlargement in eogenetic karst aquifers

Jason Gulley, Jonathan B. Martin, Elizabeth J. Screaton and Paul J. Moore
River reversals into karst springs; a model for cave enlargement in eogenetic karst aquifers
Geological Society of America Bulletin (March 2011) 123 (3-4): 457-467

Abstract

Most conceptual models of epigenic conduit development assume that conduits sourcing karst springs form as water that is undersaturated with respect to carbonate minerals flows from recharge to discharge points. This process is not possible in springs fed by distributed recharge that is transmitted through aquifer matrix porosity, such as unconfined aquifers in eogenetic carbonate rocks. Diffusely recharged water has a long residence time within the aquifer, and thus would have equilibrated with the aquifer rocks prior to discharge to the conduits. The upper Floridan aquifer has high matrix permeability ( approximately 10 (super -13) m (super 2) ), and many springs lack discrete inputs of undersaturated allogenic water in their recharge areas. Consequently, another explanation for their development is necessary. During flooding of the Suwannee River in north-central Florida, water highly undersaturated with respect to carbonate minerals commonly recharges the upper Floridan aquifer through spring vents, and solution scallops oriented away from the vents suggest most dissolution along conduit walls occurs during these flow reversals. During a single flow reversal at the Peacock Spring cave system, flood water was capable of dissolving up to 3.4 mm of the conduit wall rock. Dissolution occurs as flow reversals follow preexisting features that include joints and paleo-water-table caves. Lack of speleothems in conduits in the upper Floridan aquifer has been used as evidence that the caves formed in the phreatic zone; however, flooding would dissolve any speleothems that may have formed during previous subaerial exposure. Conduit enlargement during flow reversals suggests that dissolution can progress in the normal upstream directions, and this process may be an important driver of dissolution in any karst aquifer with outflows to surface water that are subject to flooding. Flow reversals would also introduce dissolved organic carbon and oxygen into the groundwater and provide important energy sources for cave ecosystems as well as altering redox chemistry of the aquifer water.


ISSN: 0016-7606
EISSN: 1943-2674
Coden: BUGMAF
Serial Title: Geological Society of America Bulletin
Serial Volume: 123
Serial Issue: 3-4
Title: River reversals into karst springs; a model for cave enlargement in eogenetic karst aquifers
Affiliation: University of Florida, Department of Geological Sciences, Gainesville, FL, United States
Pages: 457-467
Published: 201103
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 32
Accession Number: 2011-022471
Categories: HydrogeologyGeomorphology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 1 table, sketch maps
N24°30'00" - N31°00'00", W87°30'00" - W80°00'00"
N30°19'60" - N35°00'00", W85°34'60" - W80°45'00"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201113
Close Modal

or Create an Account

Close Modal
Close Modal