Measuring vertical tectonic motion at the intersection of the Santa Cruz-Catalina Ridge and Northern Channel Islands platform, California Continental Borderland, using submerged paleoshorelines

2008 ◽  
Vol 120 (7-8) ◽  
pp. 1053-1071 ◽  
Author(s):  
J. D. Chaytor ◽  
C. Goldfinger ◽  
M. A. Meiner ◽  
G. J. Huftile ◽  
C. G. Romsos ◽  
...  
Keyword(s):  
Channel Islands ◽  
Santa Cruz ◽  
Northern Channel Islands ◽  
Tectonic Motion ◽  
California Continental Borderland

Spatial and Temporal Variability in Chert Exploitation on Santa Cruz Island, California

2010 ◽  
Vol 75 (1) ◽  
pp. 177-198 ◽  
Author(s):  
Jennifer E. Perry ◽  
Christopher S. Jazwa
Keyword(s):  
Late Holocene ◽  
Channel Islands ◽  
Spatial And Temporal Variability ◽  
Santa Cruz Island ◽  
Santa Cruz ◽  
Shell Middens ◽  
Tool Manufacture ◽  
Radiocarbon Dates ◽  
California Channel Islands ◽  
Northern Channel Islands

Chert outcrops on eastern Santa Cruz Island were of vital importance to the inhabitants of the Santa Barbara Channel region because of their comparatively limited availablity elsewhere on the California Channel Islands. Temporally diagnostic artifacts and radiocarbon dates from associated shell middens suggest that chert quarries were exploited throughout the Holocene. The importance of these quarries has been well documented in regard to microlith production as part of the shell bead industry during the late Holocene. However, relatively little is known about local chert tool manufacture and exchange in earlier times. Systematic documentation of 26 known chert quarries, and sampling at associated shell middens on eastern Santa Cruz Island has resulted in the identification of significant spatial variability in chert exploitation through time. Whereas chert quarrying during the middle Holocene appears to have been opportunistic and dispersed throughout the landscape, comparable activities during the late Holocene became increasingly circumscribed as microlith production was intensified. These trends in chert procurement are interpreted in the context of temporal changes in subsistence, tool manufacture, and residential mobility on the northern Channel Islands, and have broad implications for spatial and temporal patterning in prehistoric lithic exploitation.

Return to Little Harbor, Santa Catalina Island, California: A Critique of the Marine Paleotemperature Model

1995 ◽  
Vol 60 (2) ◽  
pp. 287-308 ◽  
Author(s):  
L. Mark Raab ◽  
Katherine Bradford ◽  
Judith F. Porcasi ◽  
William J. Howard
Keyword(s):  
Sea Surface ◽  
Channel Islands ◽  
Short Term ◽  
Sea Temperature ◽  
Weak Evidence ◽  
Northern Channel Islands ◽  
Recent Case Study ◽  
Santa Catalina Island ◽  
Starvation Conditions

Marine paleotemperature is a significant factor in the subsistence productivity of many coastal regions and may be an important factor in the evolution of maritime societies. A California paleotemperature model, spanning 8,000 calendar years, correlates periods of high sea surface temperatures with decreased marine subsistence productivity. A recent case study involving this model identified warming conditions between A.D. 1150 to 1300 as a major cause of subsistence distress for dwellers of the northern Channel Islands. These results are questionable, based on a comparison with data from other sites and periods of high sea temperature. Research at the Little Harbor site, one of the most extensively researched in the Channel Islands, shows that high sea temperature about 5,200 calendar years ago may have introduced warm-water faunas but not starvation conditions. Evidence from other sites occupied during subsequent warming cycles, including the event between A.D. 1150 to 1300, points to similar conclusions. Understanding the effects of long- and short-term ocean temperature cycles, a focus on only a small segment of the Holocene paleotemperature curve, and weak evidence that food abundance was affected by sea temperature are problems that must be overcome before the validity of the paleotemperature model can be accepted.

A Groundwater Hypothesis for the Origin of “Fire Areas” on the Northern Channel Islands, California

1986 ◽  
Vol 26 (2) ◽  
pp. 207-217 ◽  
Author(s):  
John Cushing ◽  
Adrian M. Wenner ◽  
Elmer Noble ◽  
Marla Daily
Keyword(s):  
Low Temperature ◽  
Channel Islands ◽  
Field Observations ◽  
Human Origin ◽  
X Ray Diffraction ◽  
Radiocarbon Dates ◽  
X Ray ◽  
The Past ◽  
Northern Channel Islands ◽  
In Fire

Pleistocene areas of red sediments and carbonized vegetation on the Northern Channel Islands, California, have in the past been interpreted as caused by fires of either natural or human origin. Some are associated with darkened mammoth and bird fossils, and these fossils have been considered as having been burned by early man. Reevaluation of these so-called “fire areas” indicates that the above phenomena are the result of low-temperature (≤100°C), nonheating processes occurring in groundwater. Evidence for this conclusion is derived from field observations on fossil carbonized vegetation, and the geology of the areas. Additional evidence derives from experiments on the red sediments and fossil wood, X-ray diffraction analyses, magnetic analyses, studies on the clay minerals smectite and illite, and the demonstration that fossil mammoth bone contains sufficient Fe and Mn to account for their discoloration. Much of the carbonization of vegetation probably occurred in water rather than in fire. Radiocarbon dates from the islands will probably need to be reevaluated. These data provide evidence contrary to the concept of the occurrence of significant fires, either natural or set by early man, on the Northern Channel Islands.

The Origin of Island Mammoths and the Quaternary Land Bridge of the Northern Channel Islands, California

1978 ◽  
Vol 10 (2) ◽  
pp. 204-225 ◽  
Author(s):  
Donald Lee Johnson
Keyword(s):  
Late Quaternary ◽  
Channel Islands ◽  
Santa Barbara Channel ◽  
Santa Barbara ◽  
Land Bridge ◽  
Geological Evidence ◽  
Sea Levels ◽  
Environmental Setting ◽  
Northern Channel Islands ◽  
New Evidence

Pygmy proboscidean remains of Mammuthus exilis occur abundantly in late Quaternary deposits on the Northern Channel Islands, California. On the assumption that ancestral elephants could not have swum to the islands and must therefore have walked out, various land bridges have been hypothesized that link the northern islands to the mainland by a peninsula. Geological evidence for a land bridge, however, is lacking, and new evidence shows that elephants are excellent swimmers and skilled at crossing watergaps. The Santa Barbara Channel was narrowed to only 6 km during glacially lowered sea levels. Modern elephants swim much further, and at speeds ranging from 0.96–2.70 km/hr. Motives for California elephants to cross Pleistocene watergaps are inferred from motives that lead modern elephants in Asia and Africa to cross watergaps. These are the visual and olfactory sensing of islands and of insular food during times of drought or fire-induced food shortage. Diminutive size of M. exilis principally reflects lack of island predators, an adaption to periodic food stress in a finite forage area affected by periodic drought and fire, and an adaptation for keeping population numbers high to maintain genetic variability and to ensure survival despite accidents. A late Quaternary scenario describes the environmental setting of the Santa Barbara Channel and the conditions that led to proboscidean dispersal to the preexistent super-island Santarosae.

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