Journal article
Age and significance of the Fire Bay assemblage: An Ordovician arc fragment within the Clements Markham Belt, Northwest Ellesmere Island, Canada
Canadian journal of earth sciences, Vol.59(10), pp.639-659
06/09/2022
DOI: 10.1139/cjes-2021-0129
Abstract
The Fire Bay Formation of Trettin (1998), Clements Markham belt, Ellesmere Island, Canada, includes volcanic rocks described as Silurian in age based on Llandovery graptolites in adjacent clastic rocks. New field observations suggest the Llandovery fossils are from packages of the Silurian Danish River and/or Lands Lokk formations that are fault-bounded rather than stratigraphically tied to Ordovician sections that contain a 470.0 ± 0.2 Ma lithic tuff, volcaniclastic units with maximum depositional ages (MDA) of 466 ± 2 and 462 ± 2 Ma based on detrital zircon, volcanic clasts with ages of 498 ± 6, 478 ± 4, and 477 ± 8 Ma, and Ordovician conodonts and graptolites of Darriwilian and Sandbian age, respectively. Since the Fire Bay Formation of Trettin (1998) lacks a type section and is fault-bounded with ambiguous age relationships, Ordovician volcanic units and fault-bounded clastic rocks correlated with the Hazen Formation are both included in the Fire Bay assemblage following the original interpretations of Trettin and Nowlan (1990). The Fire Bay assemblage records juvenile Ordovician arc magmatism proximal to the Pearya terrane. The adjacent Lands Lokk Formation yields bimodal age peaks at 440–430 and 465 Ma, MDA of 424 ± 3 Ma and Hf(t) values of -5 to +5. The signature matches Ordovician Pearya units and Silurian circum-Arctic arc sources but there is no evidence for Silurian arc magmatism between the Pearya terrane and Laurentian margin, compatible with Pearya accretion during oblique Ordovician arc collision and Silurian sinistral translation along the northern Laurentian margin.
Details
- Title: Subtitle
- Age and significance of the Fire Bay assemblage: An Ordovician arc fragment within the Clements Markham Belt, Northwest Ellesmere Island, Canada
- Creators
- Megan M. Koch - University of IowaKarol Faehnrich - Dartmouth CollegeWilliam C. McClelland - University of IowaJames L. Crowley - Boise State UniversityMichael J. Melchin - St. Francis Xavier UniversityLuke P. Beranek - Memorial University of NewfoundlandJustin V. Strauss - Dartmouth College
- Resource Type
- Journal article
- Publication Details
- Canadian journal of earth sciences, Vol.59(10), pp.639-659
- DOI
- 10.1139/cjes-2021-0129
- ISSN
- 0008-4077
- eISSN
- 1480-3313
- Language
- English
- Date published
- 06/09/2022
- Academic Unit
- Earth and Environmental Sciences
- Record Identifier
- 9984274856102771
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