Origin and Diagenesis of Volcanic-Rich Sediments from North Pacific Seamounts, DSDP Leg 32

Moberly, Ralph; Keene, J.B.

doi:10.2973/dsdp.proc.32.117.1975

Cited by 6 publications

(8 citation statements)

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“…However, Matter and Gardner (1975) interpret the abundance of shallow-water benthic foraminifers, calcareous green algae, coralline algae, and ooids as indicators of a water depth of less than 4 to 6 meters. On Kökö Seamount, the absence of larger orbitoid foraminifers and the higher proportion of bryozoans to corals, which make up not more than 2 per cent of the sediment, was already noted by Moberly and Keene (1975). They concluded that "the shallow water of Kökδ Guyot during the early Eocene was not typical of the tropics."…”

Section: Environment Of Depositionmentioning

confidence: 96%

Shallow-Water Carbonate Sediments from the Emperor Seamounts: Their Diagenesis and Paleogeographic Significance

McKenzie¹,

Bernoulli²,

Schlanger³

1980

Initial Reports of the Deep Sea Drilling Project

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Deep sea drilling on four seamounts in the Emperor Seamount chain revealed that Paleogene shallow-water carbonate sediments of the "bryozoan-algal" facies crown the basalt edifices. According to the biofacies model of Schlanger and Konishi (1966, 1975), this bryozoan-algal assemblage suggests that the seamounts formed in cooler, more northerly waters than those presently occupied by the island of Hawaii; i.e., the paleolatitudes of formation were greater than 20 °N. Moving southward toward the youngest member of the seamount chain, a facies gradient indicative of warmer waters was observed. This gradient is interpreted as a reflection of a northward shift in isotherms during the time span in which the seamounts were progressively formed (Savin et al., 1975). On all seamounts, sedimentation at the drilling sites occurred in a high-energy environment with water depths of approximately 20 meters. Early-stage carbonate diagenesis began in the phreatic zone in the presence of meteoric water, but proceeded after subsidence of the seamounts into intermediate sea waters, where the bulk, stable isotopic composition was determined. The subsidence into intermediate waters was rapid, and permitted establishment of an isotopic equilibrium which, like the facies gradient, reflects the northward shift in isotherms during the Paleogene. Calcite and zeolite cements comprise the later-stage diagenesis, and originated from solutions arising from the hydrolysis of the underlying basalt.In conclusion, the results of this study of the shallow-water carbonate sediments are not inconsistent with a paleolatitude of formation for Suiko Seamount (Site 433) of 26.9 ±3.5 °N, as determined by paleomagnetic measurements (Kono, this volume).

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Section: Environment Of Depositionmentioning

confidence: 96%

Shallow-Water Carbonate Sediments from the Emperor Seamounts: Their Diagenesis and Paleogeographic Significance

McKenzie¹,

Bernoulli²,

Schlanger³

1980

Initial Reports of the Deep Sea Drilling Project

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“…Cretaceous volcaniclastic deposits are clearly linked to intraplate volcanism (e.g., Viereck et al 1985;Moberly and Keene 1975;Moberly 1981;Kelts and McKenzie 1976;Timofeev et al 1981), mid-ocean ridge systems (Vallier and Jefferson 1981), and Cretaceous oceanic plateaus (Klein 1975;Tarduno et al 1991). Emplacement of bottom-transported density flows from shallow subaqueous and subaerial volcanoes dominated (e.g., Moberly and Keene 1975;Moberly 1981) with only minor fallout components (Tarduno et al 1991). Schlanger et al (1981) suggested that the Cretaceous volcanic pulse caused regional uplift with an amplitude of approximately 1000-2000 m ("Darwin Rise") that brought many sites above the calcite compensation depth and the top of the volcanic structures near seal evel.…”

Section: Low Signal From Intraplate Volcanismmentioning

confidence: 99%

Evaluating the tephra input into Pacific Ocean sediments: distribution in space and time

Straub¹,

Schmincke²

1998

Geologische Rundschau

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We studied the volcanic contribution to the global sediment budget in the Pacific Ocean basin. It is the world's oldest (174 m.y.) and largest (≈49% of Earth's surface area) ocean basin and has had a high and continuous tephra influx from intraplate and convergent margin volcanoes through time. Computerized shipboard data from 65 legs of the Deep Sea Drilling Project (DSDP) and the Ocean Drilling Program (ODP) were screened for the presence of volcaniclastic components. Tephra-bearing and tephra-free core sections (standard 1.5-and 0.30-m core catcher sections) were separated, regardless of the mass fraction of tephra present. The percentage of tephra-bearing core sections ("tephra frequency") per site and time span ("age unit") was calculated. The age units were the Quaternary, the subepochs of the Tertiary, and the stages of the Cretaceous. A total of 424 drill sites yielded 1433 usable stratigraphic units. Fifty percent are younger than 13 m.y., corresponding to only approximately 10% of the total interval studied (124.5 m.y.). The percentage of tephra-bearing age units is high throughout (83±6%) and correlates linearly with the total number of age units (R 2 =0.998; n=17). The average tephra frequency (30-50%) fluctuates, because the abundance of age units of different tephra frequency classes (0, 1-33, 34-67, 68-100% tephra frequency) varies with time. This indicates that the Cenozoic increase in tephra production results from increase in volcanicity and not spatial extension of volcanic source areas. The Cenozoic sediments that were recovered are dominated by distal tephra from explosive arc volcanism. Pulses of arc volcanism occurred in the Pliocene-Quaternary (since ≈5 m.y.) and midMiocene (≈12-15 m.y.). However, the record of explosive arc volcanism in Paleogene and Cretaceous sediments was either not drilled or has been destroyed by subduction. Except for the Cretaceous (≈70-110 m.y.) volcanic pulse, intraplate volcanism is poorly represented in the tephra record because the drill sites are outside the proximal range (>500-1000 km) of the sources. Thus, the tephra record drilled contains significant gaps that bias the estimate of tephra volume towards the less voluminous distal deposits. Most of the volcaniclastic volume accumulated by mass wasting as volcaniclastic aprons surrounding ocean island volcanoes. Volcaniclastic production rates range from 10,000 to 41,800 km 3 /m.y. for large intraplate volcanoes and approximately 10-13 km 3 /km arc length per million years for oceanic island arcs. Extrapolation over the lifetime of major Pacific arcs and hotspot chains, combined with a volume estimate of the distal tephra component, indicates a minimum of 9.3×10 6 km 3 of tephra, corresponding to 23 vol.% of the existing Pacific oceanic sediments. At least two thirds of the tephra volume was deposited in the proximal range and at least half of it is derived from intraplate sources. The large proportion of tephra, its composition, and its localized accumulation causes significant spatial and temporal variati...

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“…Large reef benthic foraminifers were not reported. However, Moberly and Keene (1975) described rounded fragments of calcite spar that were transported to the site, presumably by the turbidity currents that deposited the enclosing volcaniclastic sandstones. We suggest that these spar fragments were derived from eroding reefs coeval with the reef skeletal debris from Sites 462, 165, 315, and 316.…”

Section: Mid-pacific Mountainsmentioning

confidence: 99%

Tectonic, Volcanic, and Paleogeographic Implications of Redeposited Reef Faunas of Late Cretaceous and Tertiary Age from the Nauru Basin and the Line Islands

Schlanger¹,

Silva²

1981

Initial Reports of the Deep Sea Drilling Project

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The age of the Pacific Plate at Deep Sea Drilling Project Site 462 is taken to be 148 m.y., based on the location of the site on Magnetic Anomaly M-26. Drilling at Site 462 however, revealed the presence of a thick volcanic complex made up of a lower sheet-flow unit and an upper sill unit which engulfed and intruded Cretaceous sediments. The igneous complex is entirely normally magnetized, indicating that it probably was emplaced during the Cretaceous long normal magnetic event which spans the period 80 to 112 m.y. ago. A ^Ar-^Ar date from a sill is 110 ±3 m.y. However, the lower flow unit is probably Barremian. A displaced reef fauna containing a Campanian-Maestrichtian pseudorbitoidid assemblage was found in a volcaniclastic section that represents the final episode of Cretaceous volcanism in the Nauru Basin-Marshall Islands area. The probable sequence of volcanic events at Site 462 appears to be (1) Menard (1964). The chronology and areal extent of Cretaceous midplate volcanism in the central Pacific is difficult to reconcile with the Wilson-Morgan hot-spot theory. We suggest that the mechanism proposed by Liu (1980), involving convection-generated stress in the lithosphere, which results in fractures allowing magma access to the surface, is an attractive alternative.Correlation of central Pacific mid-plate volcanism with volcanic events in the Caribbean and South Atlantic indicates that uplift associated with mid-plate volcanism was a major factor in causing the global Cretaceous transgression heretofore ascribed to increases in spreading rates at mid-ocean ridges.The Late Cretaceous reef faunas from the Marshall-Line Islands and the Caribbean have strong affinities, suggesting that these areas were closer together in Late Cretaceous time and that there were shallow-water "stepping stones" between them. This interpretation supports the contention of earlier workers that the present Caribbean Plate was part of the Farallon Plate in Cretaceous time.Redeposited reef faunas found in Oligocene and Miocene turbidite sequences are related to accelerated reef erosion during glacially induced sea-level falls. The Cenozoic reef assemblages, in contrast to the Cretaceous ones, have IndoPacific affinities.

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Origin and Diagenesis of Volcanic-Rich Sediments from North Pacific Seamounts, DSDP Leg 32

Cited by 6 publications

References 0 publications

Shallow-Water Carbonate Sediments from the Emperor Seamounts: Their Diagenesis and Paleogeographic Significance

Shallow-Water Carbonate Sediments from the Emperor Seamounts: Their Diagenesis and Paleogeographic Significance

Evaluating the tephra input into Pacific Ocean sediments: distribution in space and time

Tectonic, Volcanic, and Paleogeographic Implications of Redeposited Reef Faunas of Late Cretaceous and Tertiary Age from the Nauru Basin and the Line Islands

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