New ties between the Alexander terrane and Wrangellia and implications for North America Cordilleran evolution

Steve Israel; Luke Beranek; Richard M. Friedman; James L. Crowley

doi:10.1130/l364.1

The occurrence of the brachiopods Nanukidium and Atrypoidea in the Late Silurian of southeastern Alaska, Alexander terrane

Journal of Paleontology ◽

10.1017/s0022336000019740 ◽

1989 ◽

Vol 63 (4) ◽

pp. 530-533 ◽

Cited By ~ 5

Author(s):

Norman M. Savage

Keyword(s):

North America ◽

North American ◽

Canadian Arctic ◽

The North ◽

Middle Paleozoic ◽

History Of ◽

North American Craton ◽

Alexander Terrane

Previously described faunas of Early Silurian through Late Pennsylvanian age from the Alexander terrane have been endemic, or have variously suggested North American or Asiatic affinities, leaving the paleogeographic history of the terrane uncertain although indicating a location closer to North America than to Asia (Armstrong, 1970; Douglass, 1971; Savage, 1981, 1985, 1989; Savage et al., 1978; Savage and Barkeley, 1985; Soja, 1988; Vaskey, 1982). The occurrence reported here of the Canadian Arctic brachiopods Nanukidium cf. N. cunninghamensis and Atrypoidea scheii in the Alexander terrane during the Late Silurian could be additional evidence supporting the view that the Alexander terrane was not far removed from the North American craton during middle Paleozoic time.

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The first Upper Triassic silicified hypercalcified sponges from the Alexander Terrane, Gravina island and Keku Strait, Southeast Alaska

Journal of Paleontology ◽

10.1666/06-019.1 ◽

2008 ◽

Vol 82 (2) ◽

pp. 344-350 ◽

Cited By ~ 3

Author(s):

Baba Senowbari-Daryan ◽

Andrew H. Caruthers ◽

George D. Stanley

Keyword(s):

North America ◽

Great Basin ◽

Upper Triassic ◽

Western North America ◽

Southeast Alaska ◽

Cassian Formation ◽

Nayband Formation ◽

Northwestern Mexico ◽

Alexander Terrane

This paper describes the first silicified Upper Triassic (Early Norian) hypercalcified sponges known from the Alexander terrane, southeast Alaska. Sponges consist of five taxa from the Cornwallis Limestone of Keku Strait, southeast Alaska: Amblysiphonella Steinmann, Parauvanella Senowbari-Daryan and Di Stefano, Nevadathalamia cylindrica (Seilacher), N. minima n. sp., and Stellispongia (S. cf. subsphaerica Dieci, Antonacci, and Zardini). The hypercalcified sponges of the Alexander terrane as described in this paper provide paleogeographic linkage with other far-flung terranes of western North America, namely the Western Great Basin of Nevada, Stikinia of the Yukon, as well as the Antimonio terrane of northwestern Mexico. In addition, Parauvanella cf. ferdowensis is known from the Upper Triassic Nayband Formation, Iran. Finally Stellispongia cf. subsphaerica is known from the Upper Carnian Cassian Formation of the Dolomite Alps.Sponges (particularly hypercalcified inozoans, sphinctozoans, chaetetids, and sponge-like organisms) are known worldwide from many Upper Triassic reef and nonreef sites. Although Upper Triassic deposits within the Cordilleran terranes and cratonal North America do not typically contain reeflike buildups, hypercalcifying sponge-like organisms were noted as occurring as part of the intricate paleoecological structure within a biostrome along the western shoreline of Gravina Island, southeast Alaska (southern Alexander terrane). This is in contrast to Keku Strait, southeast Alaska (central Alexander terrane), where hypercalcified sponges were identified from limestone beds within nonreef deposits.

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Late Devonian (Frasnian) brachiopods from the Wadleigh Limestone, Southeastern Alaska

Journal of Paleontology ◽

10.1017/s0022336000038014 ◽

1995 ◽

Vol 69 (6) ◽

pp. 1029-1046 ◽

Cited By ~ 6

Author(s):

Norman M. Savage ◽

Mary Baxter

Keyword(s):

North America ◽

New Taxa ◽

North American ◽

Late Devonian ◽

Western North America ◽

Brachiopod Fauna ◽

General Communication ◽

Alexander Terrane

A brachiopod fauna from the upper part of the Wadleigh Limestone, Alexander terrane, southeastern Alaska, is of late Frasnian age and includes the new taxa Gypidula cornuta alaskensis n. subsp., Gypidula upatensis n. sp., Gypidula perryi n. sp., Gypiduloides craigensis n. gen. and sp., Parapugnax schmidti n. sp., Westbroekina chaconenesis n. gen. and sp., Emanuella altus n. sp., Emanuella neumani n. sp., Adolfispirifer sanjuanensis n. sp., Theodossia albertoensis n. sp., Cyrtospirifer paridaensis n. sp., and Tenticospirifer wadleighensis n. sp. A few other taxa are cosmopolitan or conspecific with species known from elsewhere in western North America. The fauna overall may have North American affinities but includes an unusual number of previously undescribed forms. This lends support to the view, based on the affinities of Frasnian conodonts from this same locality (Savage, 1992) and Famennian brachiopods described from nearby (Savage et al., 1978), that these Alexander terrane faunas were not in general communication with Late Devonian North American cratonic faunas to the east.

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