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Sequence stratigraphy, seismic stratigraphy, and seismic structures of the lower intermediate confining unit and most of the Floridan aquifer system, Broward County, Florida

Scientific Investigations Report 2017-5109

Prepared in cooperation with Broward County Environmental Planning and Community Resilience Division, Florida
By:
https://doi.org/10.3133/sir20175109

Links

  • Document: Report (36.3 MB pdf)
  • Plates:
    • Plate 1 (4.20 MB pdf) Synthetic Seismograms from Floridan Aquifer System Wells, Eastern Broward County, Florida, Part 1
    • Plate 2 (2.14 MB pdf) Synthetic Seismograms from Floridan Aquifer System Wells, Eastern Broward County, Florida, Part 2
    • Plate 3 (9.83 MB pdf) Block Models Showing Altitudes of Eight Depositional-Sequence Upper Boundaries of the Oldsmar Formation, Avon Park Formation, and Arcadia Formation, Eastern Broward County, Florida
    • Plate 4 (16.4 MB pdf) Maps Showing Altitudes of Eight Depositional-Sequence Upper Boundaries of the Oldsmar Formation, Avon Park Formation, and Arcadia Formation, Eastern Broward County, Florida
    • Plate 5 (2.38 MB pdf) Detailed Graphical Lithologic Log of the Avon Park Formation in the G–2984 Test Corehole
    • Plate 6 (24.2 MB pdf) Uninterpreted Seismic-Reflection Profile Along the Hillsboro Canal, Eastern Broward County, Florida
    • Plate 7 (24.8 MB pdf) Interpreted Seismic-Reflection Profile Along the Hillsboro Canal, Eastern Broward County, Florida
    • Plate 8 (32.4 MB pdf) Uninterpreted Seismic-Reflection Profiles Along the C-13 Canal, Eastern Broward County, Florida
    • Plate 9 (33.1 MB pdf) Interpreted Seismic-Reflection Profiles Along the C–13 Canal, Eastern Broward County, Florida
    • Plate 10 (37.6 MB pdf) Uninterpreted Seismic-Reflection Profiles Along the L–35A and L–36 Canals, Eastern Broward County, Florida
    • Plate 11 (37.8 MB pdf) Interpreted Seismic-Reflection Profiles Along the L–35A and L–36 Canals, Eastern Broward County, Florida
    • Plate 12 (20.5 MB pdf) Uninterpreted Seismic-Reflection Profiles Along the North New River Canal, Eastern Broward County, Florida
    • Plate 13 (21.1 MB pdf) Interpreted Seismic-Reflection Profiles Along the North New River Canal, Eastern Broward County, Florida
    • Plate 14 (16.8 MB pdf) Uninterpreted Seismic-Reflection Profiles Along the C–11 Canal, Eastern Broward County, Florida
    • Plate 15 (17.1 MB pdf) Interpreted Seismic-Reflection Profiles Along the C–11 Canal, Eastern Broward County, Florida
    • Plate 16 (24.7 MB pdf) Uninterpreted Seismic-Reflection Profiles Along the C–9 Canal, Miami-Dade and Broward Counties, Florida
    • Plate 17 (24.6 MB pdf) Interpreted Seismic-Reflection Profiles Along the C–9 Canal, Miami-Dade and Broward Counties, Florida
    • Plate 18 (10.7 MB pdf) Uninterpreted Seismic-Reflection Profiles Along the Eastern C–9 Canal, Oleta River, and Intracoastal Waterway, Miami-Dade County, Florida
    • Plate 19 (11.2 MB pdf) Interpreted Seismic-Reflection Profiles Along the Eastern C–9 Canal, Oleta River, and Intracoastal Waterway, Miami-Dade County, Florida
    • Plate 20 (711 kB pdf) Detailed Graphical Lithologic Log of the Arcadia Formation in the G–2984 Test Corehole
    • Plate 21 (5.77 MB pdf) Multi-Attribute Fault and Chimney Analyses of a Seismic-Reflection Profile Along the Hillsboro Canal, Eastern Broward County, Florida
  • Data Releases:
    • USGS data release - Synthetic Seismogram Data for Correlation Between Seismic-Reflection Profiles and Well Data, Broward County, Florida
    • USGS data release - Marine seismic profiles used to assess the seismic stratigraphy and structure of the intermediate confining unit and Floridan aquifer system, Broward County, Florida
  • Version History: Version History (1 MB txt)
  • Download citation as: RIS | Dublin Core

Abstract

Deep well injection and disposal of treated wastewater into the highly transmissive saline Boulder Zone in the lower part of the Floridan aquifer system began in 1971. The zone of injection is a highly transmissive hydrogeologic unit, the Boulder Zone, in the lower part of the Floridan aquifer system. Since the 1990s, however, treated wastewater injection into the Boulder Zone in southeastern Florida has been detected at three treated wastewater injection utilities in the brackish upper part of the Floridan aquifer system designated for potential use as drinking water. At a time when usage of the Boulder Zone for treated wastewater disposal is increasing and the utilization of the upper part of the Floridan aquifer system for drinking water is intensifying, there is an urgency to understand the nature of cross-formational fluid flow and identify possible fluid pathways from the lower to upper zones of the Floridan aquifer system. To better understand the hydrogeologic controls on groundwater movement through the Floridan aquifer system in southeastern Florida, the U.S. Geological Survey and the Broward County Environmental Planning and Community Resilience Division conducted a 3.5-year cooperative study from July 2012 to December 2015. The study characterizes the sequence stratigraphy, seismic stratigraphy, and seismic structures of the lower part of the intermediate confining unit aquifer and most of the Floridan aquifer system.

Data obtained to meet the study objective include 80 miles of high-resolution, two-dimensional (2D), seismic-reflection profiles acquired from canals in eastern Broward County. These profiles have been used to characterize the sequence stratigraphy, seismic stratigraphy, and seismic structures in a 425-square-mile study area. Horizon mapping of the seismic-reflection profiles and additional data collection from well logs and cores or cuttings from 44 wells were focused on construction of three-dimensional (3D) visualizations of eight sequence stratigraphic cycles that compose the Eocene to Miocene Oldsmar, Avon Park, and Arcadia Formations. The mapping of these seismic-reflection and well data has produced a refined Cenozoic sequence stratigraphic, seismic stratigraphic, and hydrogeologic framework of southeastern Florida. The upward transition from the Oldsmar Formation to the Avon Park Formation and the Arcadia Formation embodies the evolution from (1) a tropical to subtropical, shallow-marine, carbonate platform, represented by the Oldsmar and Avon Park Formations, to (2) a broad, temperate, mixed carbonate-siliciclastic shallow marine shelf, represented by the lower part of the Arcadia Formation, and to (3) a temperate, distally steepened carbonate ramp represented by the upper part of the Arcadia Formation.

In the study area, the depositional sequences and seismic sequences have a direct correlation with hydrogeologic units. The approximate upper boundary of four principal permeable units of the Floridan aquifer system (Upper Floridan aquifer, Avon Park permeable zone, uppermost major permeable zone of the Lower Floridan aquifer, and Boulder Zone) have sequence stratigraphic and seismic-reflection signatures that were identified on cross sections, mapped, or both, and therefore the sequence stratigraphy and seismic stratigraphy were used to guide the development of a refined spatial representation of these hydrogeologic units. In all cases, the permeability of the four permeable units is related to stratiform megaporosity generated by ancient dissolution of carbonate rock associated with subaerial exposure and unconformities at the upper surfaces of carbonate depositional cycles of several hierarchical scales ranging from high-frequency cycles to depositional sequences. Additionally, interparticle porosity also contributes substantially to the stratiform permeability in much of the Upper Floridan aquifer. Information from seismic stratigraphy allowed 3D geomodeling of hydrogeologic units—an approach never before applied to this area. Notably, the 3D geomodeling provided 3D visualizations and geocellular models of the depositional sequences, hydrostratigraphy, and structural features. The geocellular data could be used to update the hydrogeologic structure inherent to groundwater flow simulations that are designed to address the sustainability of the water resources of the Floridan aquifer system.

Two kinds of pathways that could enable upward cross-formational flow of injected treated wastewater from the Boulder Zone have been identified in the 80 miles of high-resolution seismic data collected for this study: a near-vertical reverse fault and karst collapse structures. The single reverse fault, inferred to be of tectonic origin, is in extreme northeastern Broward County and has an offset of about 19 feet at the level of the Arcadia Formation. Most of the 17 karst collapse structures identified manifest as columniform, vertically stacked sagging seismic reflections that span early Eocene to Miocene age rocks equivalent to much of the Floridan aquifer system and the lower part of the overlying intermediate confining unit. In some cases, the seismic-sag structures extend upward into strata of Pliocene age. The seismic-sag structures are interpreted to have a semicircular shape in plan view on the basis of comparison to (1) other seismic-sag structures in southeastern Florida mapped with two 2D seismic cross lines or 3D data, (2) comparison to these structures located in other carbonate provinces, and (3) plausible extensional ring faults detected with multi-attribute analysis. The seismic-sag structures in the study area have heights as great as 2,500 vertical feet, though importantly, one spans about 7,800 feet. Both multi-attribute analysis and visual detection of offset of seismic reflections within the seismic-sag structures indicate faults and fractures are associated with many of the structures. Multi-attribute analysis highlighting chimney fluid pathways also indicates that the seismic-sag structures have a high probability for potential vertical cross-formational fluid flow along the faulted and fractured structures. A collapse of the seismic-sag structures within a deep burial setting evokes an origin related to hypogenic karst processes by ascending flow of subsurface fluids. In addition, paleo-epigenic karst related to major regional subaerial unconformities within the Florida Platform generated collapse structures (paleo-sinkholes) that are much smaller in scale than the cross-formational seismic-sag structures.

Suggested Citation

Cunningham, K.J., Kluesner, J.W., Westcott, R.L., Robinson, Edward, Walker, Cameron, and Khan, S.A., 2018, Sequence stratigraphy, seismic stratigraphy, and seismic structures of the lower intermediate confining unit and most of the Floridan aquifer system, Broward County, Florida (ver. 1.1, January 2018): U.S. Geological Survey Scientific Investigations Report 2017–5109, 71 p., 21 pls., https://doi.org/10.3133/sir20175109.

ISSN: 2328-0328 (online)

Study Area

Table of Contents

  • Abstract
  • Introduction
  • Methods of Investigation
  • Geology and Sequence Stratigraphy
  • Hydrogeology
  • Seismic Stratigraphy
  • Seismic Structures
  • Summary and Conclusions
  • References Cited
  • Glossary

Additional publication details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Sequence stratigraphy, seismic stratigraphy, and seismic structures of the lower intermediate confining unit and most of the Floridan aquifer system, Broward County, Florida
Series title:
Scientific Investigations Report
Series number:
2017-5109
DOI:
10.3133/sir20175109
Edition:
Version 1.0: Originally released December 8, 2017; Version 1.1: January 16, 2018
Year Published:
2018
Language:
English
Publisher:
U.S. Geological Survey
Publisher location:
Reston, VA
Contributing office(s):
FLWSC-Ft. Lauderdale
Description:
Report: ix, 71 p.; 21 Plates; 2 Data Releases
Country:
United States
State:
Florida
County:
Broward County
Other Geospatial:
Floridan Aquifer System
Online Only (Y/N):
Y
Additional Online Files (Y/N):
Y