Sea Cliffs and Fronting Wave Cut Platform

Originate in settings where there is a relative sea level fall - where land surface is rising at a faster rate than sea level is rising.

West Cliff Drive, Santa Cruz, CA

Sea Cliffs and Fronting Wave Cut Platform

Sea Cliff Retreat – Processes and Timing

1. Abrasion of a Basal Notch

2. Thresholded Failure

3. Comminution Lag - Protective Feedback

Episodic Sea Cliff Failure Retreat History

Figure from Hapke and Richmond, 2002, Marine Geology

grain entrainment - abrasion - positive feedbackbeach development - wave energy dissipation - negative feedback

Sea Cliff Erosion – feedbacks*

after: Ruggiero et al., 2001

What about influence of lithology?

Correlation of Wave Runup and Sea Cliff Retreat

Tectonically Active Margin:Santa Cruz Mountains and SF Peninsula

Image courtesy of USGS / PG&E Cooperative Research

Monterey Canyon - tectonic offset

Figure from Greene et al., 1991

Highway 1 near Santa Cruz, California

Erosional Geomorphic Features - Marine Terraces

Note sharp edges of the modern (actively forming) sea cliffs and diffuse, scraps of terrace treads high in the landscape

Correspondence of Terrace Elevation with Age/SL highstand

From Merritts and Bull, 1989, Geology

Marine Terrace Generation and Degradation*

Animation by Robert S. Anderson:http://geomorph.geology.ufl.edu/~adamsp/Outgoing/Animations/bobs_terrace_movie.mov

Isostatic Uplift and Landform Preservation

Holocene Beach Ridges - Sweden - isostatic uplift from deglaciation since late Pleistocene = 2mm/yr

Isostatic Uplift of the Florida Platform

Karstostasy - Idealized

Animation by Peter N. Adams:http://geomorph.geology.ufl.edu/~adamsp/Outgoing/Animations/FlaEpeir_Run109.mov

Karstostasy – Application to Florida Through the Pleistocene

Animation by Peter N. Adams:http://geomorph.geology.ufl.edu/~adamsp/Outgoing/Animations/FlaEpeir_Run125.mov