Seamounts at the continental margin of California: A different kind of oceanic intraplate volcanism

Davis, Alicé S.; Clague, David A.; Bohrson, Wendy A.; Dalrymple, G. Brent; Greene, H. Gary

doi:10.1130/0016-7606(2002)114<0316:satcmo>2.0.co;2

Cited by 48 publications

(95 citation statements)

References 40 publications

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“…3) may have been linked to extension rather than subduction. Episodes of volcanism related to extensional tectonics have been documented for seamounts at the continental margin offshore central to southern California (Davis et al, 1995(Davis et al, , 2002. This Note that, where there were multiple analyses of the same grain, the average of those analyses is shown.…”

Section: Central Outer Borderlandmentioning

confidence: 94%

Evidence for interaction of a spreading ridge with the outer California borderland

et al. 2006

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Section: Central Outer Borderlandmentioning

confidence: 94%

Evidence for interaction of a spreading ridge with the outer California borderland

et al. 2006

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“…For magmas more enriched in volatiles, explosive fragmentation appears to be possible at much greater depths (e.g. Gill et al 1990;Clague et al 1990Clague et al , 2000Clague et al , 2002Clague et al , 2003aDavis et al 2002;Davis and Clague 2003;Head and Wilson 2003;Hékinian et al 2000;Fouquet et al 1998;Eissen et al 2003).…”

Section: Introductionmentioning

confidence: 98%

Volcaniclastic deposits from the North Arch volcanic field, Hawaii: explosive fragmentation of alkalic lava at abyssal depths

Davis

Clague

2005

Bull Volcanol

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Submarine explosive eruptions are generally considered to become less likely with increasing depth due to the increasing hydrostatic pressure of the overlying water column. Volcaniclastic deposits from the North Arch volcanic field, north of Oahu, have textural characteristics of explosive fragmentation yet were erupted in water depths greater than 4,200 m.The most abundant volcaniclastic samples from North Arch are clast-supported with highly vesicular, angular pyroclasts. They are most likely near-vent pyroclastic fall deposits formed in eruption columns of limited height. Interbedded with highly vesicular pillow lava, they form low (50 to 200 m), steep-sided cones around the vents. Less common are stratified samples with graded bedding; one such sample includes a layer of roughly aligned, platy, bubble-wall glass fragments (resembling littoral limu o Pele) that may have been deposited by density currents. In addition to bubble-wall glass shards, numerous glass fragments with spherical, delicate spindle and ribbon shapes, and Pele's hair-like glass strands occur in the finer size fraction (<0.5 mm) of some samples. They are probably more distal fallout. Another sample, consisting of glass fragments dispersed in a marine clay matrix, was apparently reworked and deposited farther from the vents by bottom currents.Glass compositions include low-(∼0.4-0.6 wt%) and medium-K 2 O (>0.6 wt%) alkalic basalt, basanite, and nephelinite. Sulfur and chlorine abundances are high, reaching a maximum of 1,800 and 1,300 ppm, respectively. The ubiquitous presence of limu o Pele fragments, regardless of glass composition, suggests that bursts of Strombolian-like activity accompanied most eruptions. Coalescing vesicles observed in larger pyroclasts and some pillow lava suggests accumulation of volatiles. Since the Editorial responsibility: J. McPhie

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“…Davidson, Pioneer, and Rodriguez Seamounts ( Fig. 1) are each 9 to 16 million yr (myr) old, have similar volcanic origins, and are located atop older oceanic crust that formed 19 to 20 myr ago (Davis et al 2002). Though formed under similar conditions, the topography, size, and summit depth of these seamounts vary (Table 1).…”

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Benthic invertebrate communities on three seamounts off southern and central California, USA

Lundsten

Barry²,

Cailliet³

et al. 2009

Mar. Ecol. Prog. Ser.

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Seamounts are unique and biologically productive deep-sea habitats that have often been described as having high levels of endemism, highly productive fisheries, and benthic communities vulnerable to trawl fishing. We describe the abundance and distribution of benthic megafaunal invertebrates found on 3 seamounts off central and southern California. Video observations were taken during 27 dives of a remotely operated vehicle (ROV) and were annotated in detail using the Monterey Bay Aquarium Research Institute's (MBARI) video annotation reference system (VARS, http://vars.sourceforge.net/). Video analysis yielded 134 477 observations of 202 identified invertebrate taxa. Video transects were analyzed to quantify organism density. Thirteen new species were observed and collected. Invertebrate communities at Davidson and Pioneer Seamounts were dominated by passive suspension-feeding cnidarians (mostly corals), but at Rodriguez Seamount, a guyot, the invertebrate community was dominated by holothurian echinoderms. We found no evidence of endemism among the megafauna at these 3 seamounts, which are all in close proximity to each other and the continental margin. KEY WORDS: Seamount biology · Deep-sea corals · Seamount invertebrate communities · Endemism Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 374: [23][24][25][26][27][28][29][30][31][32] 2009 of bycatch collected on the pinnacles and flats on the Chatham Rise. At least 2 studies have attributed higher densities of organisms, particularly corals, to areas identified as localized 'peaks' or areas of elevated topography (Genin et al. 1986, DeVogelaere et al. 2005. However, none of these studies provides a comprehensive view of factors influencing the function of seamount benthic communities in general.We examined 3 seamounts along the California continental margin. Davidson, Pioneer, and Rodriguez Seamounts ( Fig. 1) are each 9 to 16 million yr (myr) old, have similar volcanic origins, and are located atop older oceanic crust that formed 19 to 20 myr ago (Davis et al. 2002). Though formed under similar conditions, the topography, size, and summit depth of these seamounts vary (Table 1). Davidson and Pioneer Seamounts, located at the base of the continental slope 80 to 90 km from shore, have peaked summits with cones arranged along parallel ridges separated by sedimentfilled troughs. Rodriguez Seamount, 250 km south of Davidson Seamount, is only ~60 km from shore with its base midway up the continental slope. Approximately 10 myr old, Rodriguez Seamount was exposed subaerially and is now a flat-topped seamount or guyot. Like Davidson and Pioneer, Rodriguez has rugged flanks, but its summit consists of lithified sandy beach deposits with a thin sediment veneer.In the present study, we describe the benthic invertebrate communities observed on the 3 California seamounts described above. In addition, we compare the major invertebrate taxa among these seamounts in relation to abiotic properties, to infer the ...

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Seamounts at the continental margin of California: A different kind of oceanic intraplate volcanism

Cited by 48 publications

References 40 publications

Evidence for interaction of a spreading ridge with the outer California borderland

Evidence for interaction of a spreading ridge with the outer California borderland

Volcaniclastic deposits from the North Arch volcanic field, Hawaii: explosive fragmentation of alkalic lava at abyssal depths

Benthic invertebrate communities on three seamounts off southern and central California, USA

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