Graptolites From Near the Ordovician-Silurian Boundary in Illinois and Iowa

Loydell, David K.; Mallett, Andrew; Mikulic, Donald G.; Kluessendorf, Joanne; Norby, Rodney D.

doi:10.1666/0022-3360(2002)076<0134:gfntos>2.0.co;2

Cited by 17 publications

(12 citation statements)

References 4 publications

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“…Flattened specimens of M. parvulus from the Yangtze Region, China show little exposure of the sicular wall below th1 2 and a greater rhabdosome width than the present specimens. Isolated specimens from Iowa, USA, illustrated by Loydell et al (2002) show an inclined supergenicular wall and introverted apertural margins, which were also observed in this study. Melchin (2008) Stratigraphical range.…”

Section: Korenograptus Laciniosus (Churkin and Carter 1970)supporting

confidence: 83%

Earliest Silurian graptolites from Kalpin, western Tarim, Xinjiang, China

Wang¹,

Muir²,

Chen³

et al. 2015

Bull. Geosci.

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Section: Korenograptus Laciniosus (Churkin and Carter 1970)supporting

confidence: 83%

Earliest Silurian graptolites from Kalpin, western Tarim, Xinjiang, China

Wang¹,

Muir²,

Chen³

et al. 2015

Bull. Geosci.

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“…It is noteworthy that almost all of the taxa in this low-diversity assemblage are normalograptids, a feature common to relatively shallow-water assemblages of Hirnantian to early Rhuddanian age in many parts of the world, including shallow-water sections in the Hirnantian of South China (Chen et al 2000), the Hirnantian and lower Rhuddanian in parts of Laurentia (e.g. Melchin et al 1991;Loydell et al 2002), and the Hirnantian in Bohemia (Ítorch 2006).…”

Section: Discussionmentioning

confidence: 97%

Restudy of some Ordovician–Silurian boundary graptolites from Anticosti Island, Canada, and their biostratigraphic significance

Melchin¹

2008

LET

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The Ellis Bay Formation on Anticosti Island has long been recognized for the biostratigraphic importance of its latest Ordovician conodont, palynomorph, and shelly fossil assemblages. However, a sparse record of graptolites has made it difficult to correlate these assemblages with the graptolite biozonation. Restudy of some previously described and examination of newly collected normalograptid specimens from the Ellis Bay and lower Becscie formations, however, shows that biostratigraphically important taxa are present and these species provide important constraints on the age of the strata. Normalograptus parvulus and N. minor have been identified in the upper half of the Ellis Bay Formation, suggesting that these strata are late Hirnantian in age (N. persculptus Biozone). Normalograptus imperfectus and Normalograptus sp. aff. N. acceptus occur in the basal beds of the Becscie Formation, indicating that these strata are earliest Silurian. These graptolite data support the hypothesis that the positive carbon isotope excursion seen in the uppermost strata of the Ellis Bay Formation is isochronous with that seen in the Hirnantian strata at Dob's Linn, Scotland, and does not span much of the lower to mid‐Hirnantian, as is the case in Arctic Canada and Nevada, USA. Anticosti Island, Hirnantian, graptolites, Ordovician, Silurian.

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“…These specimens closely resemble N. ? parvulus in outline and although they have widths comparable to specimens referred to this taxon, they have noticeably greater 2TRDs (Lapworth 1900; Zalasiewicz & Tunnicliff 1994; Loydell et al . 2002; Chen et al.…”

Section: Stratigraphic Variation In Graptolite Morphotypesmentioning

confidence: 89%

“…parvulus displaying closer thecal spacing and narrower dorsoventral widths than P. persculptus (e.g. Williams 1983; Koren’ & Rickards 1996; Loydell et al. 2002; Chen et al .…”

Section: Graptolite Evolution and The Median Septummentioning

confidence: 99%