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Erosional Features (Typical of Active Margins). Sea cliffs, wave platform, but no pocket beach West Cliff Drive, Santa Cruz, CA. Erosional Features (Typical of Active Margins). Sea cliffs, sea stack, pocket beach between headlands Bonny Doon Beach, Central California. Bathymetry at Mavericks.
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Erosional Features (Typical of Active Margins) Sea cliffs, wave platform, but no pocket beach West Cliff Drive, Santa Cruz, CA
Erosional Features (Typical of Active Margins) Sea cliffs, sea stack, pocket beach between headlands Bonny Doon Beach, Central California
Bathymetry at Mavericks At active margins, shelf can be an erosional feature
Features associated with sea cliff retreat Formation of erosional coast features
Control on Cliff Slope relative influences of terrestrial vs. marine processes
Sea Cliff Retreat – Processes and Timing • Abrasion of a Basal Notch • Thresholded Failure • Comminution Lag - Protective Feedback Figure from Hapke and Richmond, 2002, Marine Geology Retreat History Episodic Sea Cliff Failure
Sea Cliff Retreat Rates in California ~30 cm/yr Goleta beach, Santa Barbara, CA
Sea Cliff Erosion – feedbacks grain entrainment - abrasion - positive feedback beach development - wave energy dissipation - negative feedback
fluids (R) morphology (EJ,EDC) Assessment of Wave impacts on Sea Cliffs after: Ruggiero et al., 1996, 2001
Correlation of Wave Runup and Sea Cliff Retreat after: Ruggiero et al., 2001 What about influence of lithology?
Santa Cruz Mountains and SF Peninsula Image courtesy of USGS / PG&E Cooperative Research
Monterey Canyon - tectonic offset Figure from Greene et al., 1991
Erosional Geomorphic Features - Marine Terraces Highway 1 near Santa Cruz, California
Marine Terrace Generation and Degradation Animation by Robert S. Anderson
Marine Terrace Profiles Figure from Rosenbloom and Anderson, JGR, 1994
Another view of the terraces From Anderson et al., 1999, Basin Research
Fluvial Dissection From Anderson et al., 1999, Basin Research
Isostatic Uplift and Landform Preservation Holocene Beach Ridges - Sweden - isostatic uplift from deglaciation since late Pleistocene = 2mm/yr