Rodriguez Guyot (a flat-topped submarine mountain) is located about halfway up the continental rise, offshore Santa Barbara. It is structurally similar to Guide, Gumdrop, Pioneer, and Davidson Seamounts, all located farther north at the base of the continental slope about 150 km off the central California coast.
These submarine volcanoes are morphologically distinct from typical ocean island volcanoes and seamounts in having complex, elongated structures with a distinctive northeast to southwest orientation common to many other volcanic edifices near the continental margins of Southern and Baja California (Atwater and Severinghaus, 1989; Lonsdale, 1991). They are aligned parallel to, and perhaps on top of, abandoned mid-ocean spreading ridges. Magnetic anomalies outboard from Rodriguez are Chron 5E indicating it is located on 19 million year old ocean crust (Atwater and Severinghouse, 1989). Rocks recovered from Rodriguez Guyot are alkalic basalt and hawaiite (Davis et al., 1995; and submitted) and have been dated by Ar-Ar techniques that indicate that the volcano is 10 to 12 million years old (Davis et al., 1995; and submitted). These seamounts, including Rodriguez, are the product of intraplate oceanic volcanism unrelated to hot spots (Davis et al., submitted).
Rodriguez Guyot rises about 1,675 meters above the surrounding seafloor to a minimum water depth of 650 meters. Its calculated volume of 205 km3 is probably a minimum value because the survey did not cover the lowermost slopes (Davis et al., submitted). The NE fabric is less well-defined than for most of the other seamounts, and large volcanic cones are also present. The largest of the cones is 700 m tall and 2.2 km across at the base and has a volume of about 2.6 km3. The sediment drape on the lower flanks of the volcano has slumped, particularly on the southwest flank. Another slump on the west flank has a field of blocky debris at its base, suggesting that the volcanic basement also slumped.
Perspective view from the south
|Index Map||Arguello Canyon||Santa Barbara Basin||Rodriguez Seamount|