Lower middle ordovician chitinozoa from the southern Appalachians, United States

1984 ◽  
Vol 43 (1-3) ◽  
pp. 89-122 ◽  
Author(s):  
Yngve Grahn ◽  
Stig M. Bergström
Keyword(s):  
United States ◽  
Southern Appalachians ◽  
Middle Ordovician

scholarly journals First record of a nonpaleotropical intejocerid cephalopod from Darriwilian (Middle Ordovician) strata of central Spain

2019 ◽  
Vol 94 (2) ◽  
pp. 273-278
Author(s):  
Björn Kröger ◽  
Juan Carlos Gutiérrez-Marco
Keyword(s):  
United States ◽  
New Species ◽  
New Genus ◽  
First Record ◽  
The United States ◽  
Central Spain ◽  
Middle Ordovician ◽  
A New Species

AbstractThe order Intejocerida is an enigmatic, short-lived cephalopod taxon known previously only from Early–Middle Ordovician beds of Siberia and the United States. Here we report a new genus, Cabaneroceras, and a new species, C. aznari, from Middle Ordovician strata of central Spain. This finding widens the paleogeographic range of the order toward high-paleolatitudinal areas of peri-Gondwana. A curved conch, characteristic for the new genus, was previously unknown from members of the Intejocerida.UUID: http://zoobank.org/21f0a09c-5265-4d29-824b-6b105d36b791

Detrital zircon populations of the eastern Laurentian margin in the Appalachians

Geology ◽  
2020 ◽  
Author(s):  
Yvette D. Kuiper ◽  
Christopher Hepburn
Keyword(s):  
United States ◽  
Detrital Zircon ◽  
Orogenic Belt ◽  
Grenville Province ◽  
Zircon Age ◽  
Zircon Population ◽  
Middle Ordovician ◽  
Archean Crust ◽  
Laurentian Margin

Newly compiled U-Pb detrital zircon data from eight geographic domains along the eastern Laurentian margin from Newfoundland (Canada) to Alabama (United States) show a highly consistent signature along strike, with only minor local variations. The Precambrian signature is characterized by a small ca. 2.7 Ga population and a major ca. 1.9–0.9 Ga population that peaks at ca. 1.2–1.0 Ga. Detrital zircon populations are from Laurentian Archean crust (ca. 2.7 Ga population), Paleoproterozoic orogens (ca. 1.9–1.6 Ga), the Granite-Rhyolite Province (ca. 1.5–1.4 Ga), and the Elzevir terrane and Grenville Province (ca. 1.3–0.9 Ga). The Mesoproterozoic populations vary in size depending on proximity to the ca. 1.5–1.4 Ga Granite-Rhyolite Province, the ca. 1245–1225 Ma Elzevir terrane, and the ca. 1.2–0.9 Ga Grenville Province. A middle Ordovician zircon population varies in size along strike depending on input from the Taconic orogenic belt, but it is strongest in the northern Appalachians. Because of the general along-strike consistency in detrital zircon age populations, the compilation of all 7534 concordant U-Pb detrital zircon data can be used in future U-Pb detrital zircon studies as an indicator for eastern Laurentian margin sources.

Age and correlation of the Honorat Group, southern Gaspé Peninsula

1988 ◽  
Vol 25 (10) ◽  
pp. 1618-1628 ◽  
Author(s):  
John Riva ◽  
Michel Malo
Keyword(s):  
United States ◽  
North America ◽  
New Brunswick ◽  
Wide Distribution ◽  
Late Ordovician ◽  
Eastern North America ◽  
North Central ◽  
Middle Ordovician ◽  
The Pacific ◽  
Early Late

The Honorat Group of southern Gaspé consists of two formations: the Arsenault and the Garin. The Arsenault Formation, heretofore considered barren, has yielded a graptolite faunule indicative of a Llanvirn–Llandeilo age (early Middle Ordovician), suggesting a correlation with the lower Mictaw Group of Gaspé as revised by de Broucker. A hiatus of indeterminate magnitude, corresponding to the Taconic unconformity, probably separates the Arsenault Formation from the overlying Garin Formation. The Garin has yielded graptolites ranging from the upper Climacograptus spiniferus Zone to the Paraclimatograptus manitoulinensis Zone (late Middle to early Late Ordovician). The C. spiniferus Zone graptolites are identical to those of the upper γ sequence of the Cloridorme Formation of northern Gaspé and the Blind Brook Formation of the Munsungun Anticlinorium of Maine but differ somewhat from those from the upper Tetagouche Group of New Brunswick, which are closer to those from the Summerford and Exploits groups of north-central Newfoundland. The C. spiniferus zone has a wide distribution in eastern North America. It correlates with the Orthograptus amplexicaulis Zone of the southwestern United States and with the Climacograptus baragwathi Zone (Ea2) of the Pacific faunal province.The Matapédia Group, stratigraphically above the Honorat Group, has yielded both shelly fossils and a few graptolites. The ages of the graptolites now date it as Late Ordovician to late Early Silurian (Dicellograptus complanatus Zone – Monograptus sedgwickii Zone).

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