GEOSCAN Search Results: Fastlink


TitleGeophysical investigation and reconstruction of lithospheric structure and its control on geology, structure, and mineralization in the Cordillera of northern Canada and eastern Alaska
AuthorHayward, N
SourceTectonics vol. 34, issue 10, 2015 p. 2165-2189,
Alt SeriesEarth Sciences Sector, Contribution Series 20140481
Mediapaper; on-line; digital
File formatpdf
NTS94; 95; 96; 104; 105; 106; 107; 114; 115; 116; 117
AreaAlaska; Canada; United States
Lat/Long WENS-152.0000 -122.0000 70.0000 56.0000
Subjectstectonics; geophysics; tectonic environments; tectonic setting; tectonic interpretations; lineaments; terranes; geophysical interpretations; mineralization; Tintina Fault; Mesozoic; Proterozoic
Illustrationslocation maps; images; profiles
ProgramWestern Cordillera, Redefinition of crustal blocks, GEM2: Geo-mapping for Energy and Minerals
AbstractA reconstruction of the Tintina Fault is applied to regional potential field and topographic data, facilitating the definition of continuous lineaments within the lower crust and/or mantle lithosphere. The lineaments are modeled and interpreted to be related to a transfer zone (Laird transfer zone) dividing zones of lower and upper plate rifting of the Laurentian margin, that is interpreted as having been continuous at least as far west as the Denali Fault. This interpretation suggests that hyper-extended North American basement, which would have brought rocks of the mantle lithosphere to a shallow depth, also underlies western Yukon. This explains the presence of North American basement in western Yukon and eastern Alaska, and a mechanism of emplacement of ultramafic rocks of oceanic crustal affinity in overlying terranes during later tectonic events, as evidenced by the abundant occurrences on regional geological maps.
The Liard transfer zone coincides with a change from unimodal mantle xenolith suites to the north from bimodal suites to the south, and gravity models suggest a subtle variation in the density of the mantle lithosphere. Spatial relationships between the lithospheric lineaments, variably manifest by potential field anomalies and models, topography, geology, and mineral occurrences, suggests that the lineaments influenced the development of the shallow crustal structure, intrusion, uplift and erosion, and possibly even the focusing of mineralisation in the North American basement and overlying terranes.
Summary(Plain Language Summary, not published)
Faults and fractures in the deep crust of the Canadian Cordillera of Yukon, Northern British Columbia and Alaska are investigated in relation to their influence on geology and mineral deposits. The relationships between structures across the region were disrupted by approximately 440 km of ancient movement on the northwest trending Tintina fault. Therefore, all of the data and maps used in the study were corrected for this movement prior to interpretation. Deep east-west trending structures, related to the ancient edge of the North American continent, are revealed to be continuous across Yukon. These structures are shown, from the interpretation of a broad range of data, to have influenced the distribution of a range of rock types, the location of faults and associated mineral deposits, and the development of the lands topography through uplift and erosion.