Chemical correlation of K-bentonite beds in the Middle Ordovician Decorah Subgroup, upper Mississippi Valley

Kolata, Dennis R.; Frost, J.K.; Huff, Warren D.

doi:10.1130/0091-7613(1987)15<208:ccokbi>2.0.co;2

Cited by 75 publications

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“…Chemostratigraphic and biostratigraphic data were used to evaluate the regional distribution pattern. We conclude from this study that the Osmundsberg K-bentonite is present in all of these localities and that it represents a subduction-related, explosively erupted felsic ash with a magnitude and character similar to some of the thickest and most widespread Ordovician ash beds (Kolata, Frost & Huff, 1987;Huff & Kolata, 1990;Huff et al 1996). This paper reports the mineralogical and geochemical characteristics of the Osmundsberg bed that form part of the basis for this conclusion.…”

Section: Introductionmentioning

confidence: 76%

“…Previous studies have shown that Palaeozoic K-bentonites can be correlated on a regional scale by using whole rock chemical fingerprinting based on trace element ratios, despite the alteration of primary glass. Kolata et al (1987) and Huff & Kolata (1989), for example, used between-bed differences in certain trace elements to distinguish between, and correlate, the Middle Ordovician Deicke and Millbrig K-bentonites in the eastern Midcontinent of North America. This method, which is based on the relative frequency of mainly immobile trace elements in each ash bed, has proved to be a powerful tool for distinguishing between ashes from different eruptions, particularly when used in conjunction with biostratigraphic and lithostratigraphic information.…”

Section: Chemical Fingerprintingmentioning

confidence: 98%

“…After Sm/Nd is entered, less than 1 % of the between-group variance is unexplained. These elements were also found to be effective in chemical fingerprinting of the Millbrig in North America (Kolata, Frost & Huff, 1987). Eight samples from beds which we believe to be the same as the Osmundsberg were then entered as unknowns and their discriminant scores computed.…”

Section: Chemical Fingerprintingmentioning

confidence: 99%

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The Lower Silurian Osmundsberg K-bentonite. Part II: mineralogy, geochemistry, chemostratigraphy and tectonomagmatic significance

et al. 1998

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The Lower Silurian Osmundsberg K-bentonite is a widespread ash bed that occurs throughout Baltoscandia and parts of northern Europe. This paper describes its characteristics at its type locality in the Province of Dalarna, Sweden. It contains mineralogical and chemical characteristics that permit its regional correlation in sections elsewhere in Sweden as well as Norway, Estonia, Denmark and Great Britain. The < 2 µm clay fraction of the Osmundsberg bed contains abundant kaolinite in addition to randomly ordered (RO) illite/smectite (I/S). Modelling of the X-ray diffraction tracings showed the I/S consists of 18 % illite and 82 % smectite. The high smectite and kaolinite content is indicative of a history with minimal burial temperatures. Analytical data from both pristine melt inclusions in primary quartz grains as well as whole rock samples can be used to constrain both the parental magma composition and the probable tectonic setting of the source volcanoes. The parental ash was dacitic to rhyolitic in composition and originated in a tectonically active collision margin setting.Whole rock chemical fingerprinting of coeval beds elsewhere in Baltoscandia produced a pronounced clustering of these samples in the Osmundsberg field of the discriminant analysis diagram. This, together with well-constrained biostratigraphic and lithostratigraphic data, provides the basis for regional correlation and supports the conclusion that the Osmundsberg K-bentonite is one of the most extensive fallout ash beds in the early Phanerozoic. The source volcano probably lay to the west of Baltica as part of the subduction complex associated with the closure of Iapetus. Figure 14. Results of preliminary studies of mineralogical ratios between the type Osmundsberg bed and its nearest correlative at Kallholn, some 20 km distant. Biotite and quartz are by far the most abundant non-clay phases present and this suggests that they may also constitute an additional physical parameter for stratigraphic usage.

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Section: Introductionmentioning

confidence: 76%

Section: Chemical Fingerprintingmentioning

confidence: 98%

Section: Chemical Fingerprintingmentioning

confidence: 99%

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The Lower Silurian Osmundsberg K-bentonite. Part II: mineralogy, geochemistry, chemostratigraphy and tectonomagmatic significance

et al. 1998

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“…Airfall pyroclastic ash beds may be widely distributed by prevailing winds in contrast to lavas, ignimbrites and ash-flow tuffs, which tend to accumulate near their source volcanoes. Kolata, Frost & Huff (1987) and Huff & Kolata (1990) have documented single K-bentonite beds of airfall origin in the Middle Ordovician of eastern North America which extend at least 1300 km from their source volcanoes. For the entire Ordovician of North America approximately 50 K-bentonite beds occur in the eastern midcontinent, mainly in the A. tvaerensis conodont Zone of the Mohawkian Series (early Caradoc).…”

Section: Introductionmentioning

confidence: 97%

Distribution and tectonic setting of Ordovician K-bentonites in the United Kingdom

et al. 1993

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Twenty-five Ordovician K-bentonite samples ranging in age from Llanvirn to Ashgill and representing both sides of the Iapetus suture were analysed by INAA and XRF and compared on magmatic and tectonic discrimination diagrams. The proportional distribution of Nb, Y, Ti, Zr, Hf, Ta, Th and REE indicates that source volcanics were erupted in a setting that changed from subduction-related in the Llanvirn/Llandeilo to marginal basin extensional volcanism in the Caradoc/Ashgill. Welsh K-bentonites appear to be derived from volcanoes within the Welsh Basin, but K-bentonites from the Southern Uplands to not have characteristics consistent with a fore-arc setting, further suggesting a source related to ensialic marginal basin extensional volcanism.

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“…The La Salle Anticlinorium lies within the Illinois Basin and trends north-south just east of the long axis of the Illinois Basin. The Reelfoot Rift and Rough Creek Graben intersect in the southern part of the basin (Kolata and Nimz, 2010; Fig. 1).…”

Section: Location and Geology Of The Mt Simon Sandstone And Ironton-mentioning

confidence: 97%

Isotopic and geochemical characterization of fossil brines of the Cambrian Mt. Simon Sandstone and Ironton–Galesville Formation from the Illinois Basin, USA

Labotka

Panno

Locke

et al. 2015

Geochimica et Cosmochimica Acta

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Geochemical and isotopic characteristics of deep-seated saline groundwater provide valuable insight into the origin and evolving composition, water-rock interaction, and mixing potential of fossil brines. Such information may yield insight into intra-and interbasinal brine movement and relationships between brine evolution and regional groundwater flow systems. This investigation reports on the d 18 O and dD composition and activity values, 87 Sr/ 86 Sr ratios and Sr concentrations, and major ion concentrations of the Cambrian-hosted brines of the Mt. Simon Sandstone and Ironton-Galesville Formation and discusses the evolution of these brines as they relate to other intracontinental brines. Brines in the Illinois Basin are dominated by Na-Ca-Cl-type chemistry. The Mt. Simon and overlying Ironton-Galesville brines exhibit total dissolved solids concentrations of $195,000 mg/L and $66,270 mg/L, respectively. The dD of brine composition of the Mt. Simon ranges from À34& to À22& (V-SMOW), and the Ironton-Galesville is $À53.2& (V-SMOW). The d 18 O composition of the Mt. Simon brine ranges from À5.0& to À2.8& (V-SMOW), and the Ironton-Galesville brine is $À6.9& (V-SMOW). The 87 Sr/ 86 Sr values in the Mt. Simon brine range from 0.7110 to 0.7116. The less radiogenic Ironton-Galesville brine has an average 87 Sr/ 86 Sr value of 0.7107. Evaluation of d 18 O and dD composition and activities and 87 Sr/ 86 Sr ratios suggests that the Mt. Simon brine is likely connate seawater and recirculating deep-seated brines that have been diluted with meteoric water and influenced by the dissolution of evaporites with a minimal halite contribution based on Cl/Br ratios. The IrontonGalesville brine is also likely originally connate seawater that mixed with other brines and meteoric waters, including possibly Pleistocene glacial recharge. The Ca-excess vs. Na-deficiency comparison with the Basinal Fluid Line suggests the Mt. Simon and Ironton-Galesville brines have been influenced by the effects of albitization and plot very close to the Basinal Fluid Line. These Cambrian-hosted brines appear to have a different albitization history than other regional basin brines and a strong component of seawater. The Ironton-Galesville brine appears more geochemically associated with other Illinois Basin brines than the Mt. Simon brine which appears more geochemically conservative. Comparisons with other extrabasinal North American brines suggest that the Michigan basin brines are geochemically most similar to the Mt. Simon brines with the exception of the influence from carbonates in the Michigan Basin. Analyses of 87 Sr/ 86 Sr values in the Mt. Simon brine suggest that brine Sr has isotopically equilibrated with clay minerals in the Lower Mt. Simon and underlying bedrock formations and not with whole rock suggesting the influence of recirculating brines from the crystalline basement. Overall, the geochemistry of these Cambrian-hosted brines suggests an evolution from original seawater-like compositions. This investigation shows that intracratonic b...

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Chemical correlation of K-bentonite beds in the Middle Ordovician Decorah Subgroup, upper Mississippi Valley

Cited by 75 publications

References 0 publications

The Lower Silurian Osmundsberg K-bentonite. Part II: mineralogy, geochemistry, chemostratigraphy and tectonomagmatic significance

The Lower Silurian Osmundsberg K-bentonite. Part II: mineralogy, geochemistry, chemostratigraphy and tectonomagmatic significance

Distribution and tectonic setting of Ordovician K-bentonites in the United Kingdom

Isotopic and geochemical characterization of fossil brines of the Cambrian Mt. Simon Sandstone and Ironton–Galesville Formation from the Illinois Basin, USA

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