Blurb:

Islands occupied since the Late Pleistocene have undergone major geographic changes that affected human settlement and behaviour. I discuss the effects of post-glacial sea level rise on the geography of California’s Northern Channel Islands (NCI), documenting the dynamic nature of seascapes that maritime people encountered over the last 13,000 years or more. Today the NCI are located 19 to 44 km from the mainland, with four islands separated by three substantial water gaps 5.6 to 8.8 km wide. Lower Terminal Pleistocene sea levels caused the NCI to coalesce into a single island known as Santarosae,~125 km long and separated from the mainland by as little as 10 km. Santarosae lost ~65 percent of its landmass over the past 15,000 years, breaking into four islands between ~11,000 and 9,000 years ago. Paleocoastal peoples who occupied Santarosae experienced a fundamentally different seascape than later island peoples, with: (1) significantly shorter minimum voyaging distances to the mainland; (2) stronger currents running through this narrower gap; (3) a single long island whose southern coast was more sheltered from prevailing northwesterly winds and seas; and (4) an inability to use boats to cut across the three straits that separate the NCI today.