Ordovician K-bentonites of eastern North America

Kolata, Dennis R.; Huff, Warren D.; Bergström, Stig M.

doi:10.1130/spe313

Cited by 46 publications

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“…173-6). As with interpretations for the older Appalachian K-bentonites, an Appalachian source is plausible incorporating southeasterly to northwesterly palaeowind directions (Kolata, Huff & Bergström, 1996). More distal sources could exist with stratospheric circulation (Delano et al 1990).…”

Section: C Plinian-scale or Basin-restricted Eruption?mentioning

confidence: 75%

“…K-bentonites younger than the Russell Bed within the Early Silurian shale/limestone successions of Scotland and Scandinavia identify acidic to intermediate, andesite, trachyandesite and trachyte sources (Fig. Light REE enrichment of the Russell Bed is calculated to be La N /Yb N = 3.1, compared to La N /Yb N = 11.2 for Deicke and La N /Yb N = 9.1 for Millbrig K-bentonite (Kolata, Huff & Bergström, 1996). Some overlap is evident.…”

Section: B Composition Of the Russell Magmatic Sourcementioning

confidence: 94%

“…The presence of R3 I/S with < 10 % smectite likely defines smectite to illite diagenesis involving dissolution of I/S and crystallization of illite (Kolata, Huff & Bergström, 1996). The presence of R3 I/S with < 10 % smectite likely defines smectite to illite diagenesis involving dissolution of I/S and crystallization of illite (Kolata, Huff & Bergström, 1996).…”

Section: A An Altered Ash Bedmentioning

confidence: 95%

“…The bed occurs at the lower-upper unit boundary of the Billings Formation, 12 m above the top of the carbonate platform. Gamma ray logs and possible regional correlation are shown for Locs A2, B, C (Bergström & Mitchell, 1994;Kolata, Huff & Bergström, 1996;Sharma, Dix & Riva, 2003). 1b; Sharma, Dix & Riva, 2003), ∼ 451-2 Ma in age (Webby et al 2004).…”

Section: Stratigraphic Frameworkmentioning

confidence: 99%

“…Fields for Mid-Ocean Ridge Basalt (MORB) and continental crust are fromKolata, Huff & Bergström (1996). Fields for Mid-Ocean Ridge Basalt (MORB) and continental crust are fromKolata, Huff & Bergström (1996).…”

mentioning

confidence: 99%

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Petrology and potential tectonic significance of a K-bentonite in a Taconian shale basin (eastern Ontario, Canada), northern Appalachians

2005

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A 6 cm thick K-bentonite, herein defined as the Russell Bed, occurs in an Upper Ordovician deep-basin shale succession in eastern Ontario, Canada, forming part of the distal Taconic foreland in eastern North America. The bed lies within the pygmaeus graptolite Biozone, which is about 451 to 452 Ma in age. Although some bentonites are reported from this interval in eastern North America, we are reporting the first set of compositional data for a bentonite of this age. Gamma-log correlation identifies a potential minimum distribution area of < 2 × 10 5 km 2 for the K-bentonite, covering part of southern Quebec, New York State and eastern Ontario. The deposit coincides with the first influx of distal turbdites into this shale basin, associated with Taconic flysch, and simultaneous abrupt ventilation of the once anoxic deep-water basin, which had formed initially after foundering of the Upper Ordovician carbonate platform. Concurrent intrabasinal extinction of several graptolite species suggests that change in sedimentation, palaeoceanography and volcanism were linked to a regional external process. Compositionally, the bentonite is distinct from the older Ordovician platform deposits in eastern North America. The deposit contains abundant titaniferous phlogopite with 1.6 % BaO, fluoroapatite with 2.5 % F, and dynamically shaped glass spherules now altered to clay. The spherules and clay matrix constitute 45 % of the bed and, compositionally, define an illite (> 90 %)smectite (I/S) structure with about 7.5 % K 2 O %. Age-dating by Ar-Ar analysis of the phlogopite crystals yielded a younger than expected (440-445 Ma) age. This difference, along with evidence of localized chloritization of phlogopite, likely reflects known post-Ordovician hydrothermal activity within the basin. On the basis of several geochemical proxies, the magmatic source of the Russell K-bentonite falls within the trachyandesite field and was Ba-enriched. Comparison of geochemistry and mineralogy with older, Middle to Late Ordovician and younger Early Silurian K-bentonites within the Taconic orogen along eastern Laurentia and Baltica reveals that the potential source magma for the Russell Bed was more mafic, more alkaline, and less fractionated than sources typical of older (platform) bentonites. Instead, it is more similar to the younger Llandovery bentonites of Scandinavia and Scotland. It remains uncertain if it signals local or regional compositional change in volcanic source in the northern Appalachians.

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Section: C Plinian-scale or Basin-restricted Eruption?mentioning

confidence: 75%

Section: B Composition Of the Russell Magmatic Sourcementioning

confidence: 94%

Section: A An Altered Ash Bedmentioning

confidence: 95%

Section: Stratigraphic Frameworkmentioning

confidence: 99%

mentioning

confidence: 99%

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Petrology and potential tectonic significance of a K-bentonite in a Taconian shale basin (eastern Ontario, Canada), northern Appalachians

2005

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An ultrasonic method for isolating nonclay components from clay‐rich material

Hoke

Schmitz

Bowring

2014

Geochem Geophys Geosyst

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[1] We present an efficient method for high-volume heavy mineral separation from clay-rich rocks using an ultrasonic probe. The ultrasonic clay separator (UCS) is an easily constructed device that allows for the recovery of high-density minerals, as small as 10 mm, with a minimum of sample preparation. Heavy mineral recovery from clay-rich material with the UCS yields a greater number of small (<100 mm) grains and approximately double the amount of material from that of gravity settling and decanting. Despite development with heavy mineral recovery in mind, the UCS should suitable for recovering small grain size geologic materials from flocculating clay-rich material.

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The Cincinnati Arch: A Stationary Peripheral Bulge during the Late Ordovician

Pope¹,

Holland²,

Patzkowsky³

2009

Perspectives in Carbonate Geology

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Shallow-water features, including peritidal carbonate complexes, tidally-influenced shoal-water facies, biostromes, and coincident subaerial unconformities on the peritidal complexes are restricted to the Cincinnati Arch during the Late Ordovician Taconic Orogeny. Persistence of these features along the Cincinnati Arch indicate this area experienced decreased subsidence relative to surrounding areas, forming the peripheral bulge within the Taconic foreland basin.These shallow-water features are surrounded on all sides by deeper water, shallow subtidal to deep subtidal facies. The Jessamine and Nashville Domes were prominent topographic highs on the arch and were the locus of shallow-water deposition and subaerial erosion, but many of these shallow-water features also occur in the subsurface between these two domes.The shallow-water features and unconformities on the Cincinnati Arch occur in a narrow band repeatedly throughout the Late Ordovician. The width of these features is much too narrow to have formed solely by flexure of the lithosphere and their persistent formation in the same location indicates they did not form as a viscoelastic response to orogenesis. Rather the boundary between the Grenville Front and the Eastern Granite-Rhyolite Province acted as a focusing mechanism for the orogenic load stresses to the east, producing a relatively stationary peripheral bulge. A temporal and spatial change in the stratigraphy and subsidence on the Nashville and Jessamine Domes during the Edenian likely records a northward shift of loading, possibly sedimentary loading, during the Taconic Orogeny.

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Ordovician K-bentonites of eastern North America

Cited by 46 publications

References 0 publications

Petrology and potential tectonic significance of a K-bentonite in a Taconian shale basin (eastern Ontario, Canada), northern Appalachians

Petrology and potential tectonic significance of a K-bentonite in a Taconian shale basin (eastern Ontario, Canada), northern Appalachians

An ultrasonic method for isolating nonclay components from clay‐rich material

The Cincinnati Arch: A Stationary Peripheral Bulge during the Late Ordovician

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