U.S. Geological Survey Open-File Report 2007-1373
High-Resolution Geologic Mapping of the Inner Continental Shelf: Cape Ann to Salisbury Beach, Massachusetts
Title Page / Table of Contents / List of Figures / Introduction / Maps / Data Collection/Processing / Interpretation / Summary / Acknowledgments / References Cited / Appendix 1 / Appendix 2 / Appendix 3 / Appendix 4 / Appendix 5
Table 4.1. Description of physiographic zones. [<, less than; >, greater than.]
| ZONE | DESCRIPTION | AREA (km²) |
AREA (percent) |
|---|---|---|---|
| Rocky Zone (RZ) | rugged, high-relief outcrops; bedrock, boulders and gravel; water depths 0–90 m | 18.3 | 5.1 |
| Nearshore Ramp (NR) | gently seaward sloping; sand and gravel; complex bedforms; water depths 0–50 m | 228.4 | 63.9 |
| Ebb-Tidal Delta (ETD) | broad platforms seaward of inlets; sandy; lobate in plan view; water depths < 8 m | 10.6 | 3.0 |
| Shelf Valley (SV) | elongate depressions with rocky walls; sand and gravel in thalwegs; water depths 12–25 m | 1.1 | 0.3 |
| Outer Basin (OB) | expansive, smooth seafloor; muddy; thick sediment deposits; water depths > 50 m | 99.1 | 27.7 |
| Total | 357.5* | 100.0 |
*In addition to areas completely imaged with sonar, the geologic map in figure 4.3 includes adjacent shallow-water areas along the coast.
