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Coastal & Marine Geology Program > Center for Coastal & Regional Marine Studies > Geologic Characterization of Lakes and Rivers of Northeast Florida > OFR 00-180

Subsurface Characterization of Selected Water Bodies in the St Johns River Water Management District, Northeast Florida

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Lake Magnolia
Clay County, Florida

Introduction | Subsurface Characterization

Introduction

Magnolia Lake Seismic Track Map.
Seismic Survey Track Map. Click on the image to see a larger version.
Lake Magnolia is on the southwest boundary of Clay County, Florida and is located in the Interlachen Sand Hills of the Central Lakes District (see Fig 7, Regional Geology). Lake level at the time of the seismic survey was 38 m (125 ft) NGVD. Lake Magnolia is oval shaped approximately 1.1 x 0.9 km with a perimeter of 3.2 km and surface area 0.8 km2. Average water depth during the survey was 6 to 7 m (19 to 23 ft). The lake is bordered by woodlands. Lake Magnolia is flanked on the west by the Trail Ridge deposits with Citronella deposits elsewhere. The lake is underlain by Citronella sediments (Clark, 1964) which consist of a relatively thick section of unconsolidated to semi-consolidated quartz sands, clayey sands, and gravels (see Fig, 5, Regional Geology). The Trail Ridge sands are above an elevation of 45 m (149 ft) and are mined commercially for heavy minerals used in paints and abrasives. The sediments are unconsolidated and completely saturated, this enhances the filling process when sinkholes collapse or sediment is washed into the lakes by surface runoff. Generally the sands are seismically transparent but clay stringers or cementation may provide reflecting horizons.
Coastal & Marine Geology Program > Center for Coastal & Regional Marine Studies > Geologic Characterization of Lakes and Rivers of Northeast Florida > OFR 00-180

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Updated December 05, 2016 @ 11:25 AM (JSS)