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Yukon–Tanana Terrane

April 08, 2024

The Yukon–Tanana Terrane (YTT) is a tectonic terrane that extends from central Alaska through central Yukon and into northern British Columbia, Canada and Southeast Alaska, USA. Extending over 2000 km, the YTT is the largest tectonostratigraphic terrane in the northern North American Cordillera.[1] The Yukon–Tanana Upland is a physiographic province mostly underlain by rocks of the Yukon–Tanana Terrane.[2]

The Yukon–Tanana Terrane (yellow) stretches across Alaska, Yukon, and British Columbia. Kaltag–Tintina fault (north of YTT) and Denali-Fairweather Fault (south of YTT) in white.

Understanding and definition of the YTT is constantly progressing, the term "Yukon Tanana composite terrane," or "YTCT" is used by some workers, reflecting the disparate depositional and tectonic histories being recognized in rock units within the YTT.[3] Since 2010, some work dispenses altogether with the term Yukon–Tanana Terrane, in favor of more detailed subdivisions.

Tectonic history edit

The YTT consists of polymetamorphosed and polydeformed metasedimentary, metavolcanic, and metaplutonic rocks of Upper Paleozoic and older ages that were deposited or emplaced near the edge of the North American continental margin.[2][4] Rocks in the terrane record a variety of tectonic settings and have experienced varying amounts of tectonic transport, both before and after amalgamation of the YTT with North America. Sequences of mainly parautochthonous quartz-rich sedimentary rocks derived from the North American continent also include meta-igneous rocks with mostly continental geochemical and isotopic signatures. Structurally higher sequences contain meta-igneous rocks with arc and back-arc characteristics. The Slide Mountain/Seventymile Terrane, composed of volcanic rocks typical of seafloor and of typical seafloor sediments, is recognized as an ocean basin that divided parts of the YTT before amalgamation of the Yukon–Tanana Terrane with the continental margin.[5][6]

The right-lateral strike slip Tintina Fault occurs along the suture zone between the YTT (on the south and west) and ancestral North America to the east; it forms a significant boundary between North America cratonic rocks and rocks of the YTT and associated terranes, although displaced continental rocks are found south of the Tintina Fault and pieces of the YTT occur north of the Tintina Fault.[7][8] Parts of the YTT have been offset by at least 400 km (250 mi) along the Tintina Fault. In most of the Alaskan part of the YTT the Denali Fault forms the modern day southern boundary of the terrane.[9] In Yukon the ocean-basin rocks of the Windy–McKinley terrane (in western Yukon), and the Coast Plutonic Complex (CPC) form the southern boundary of the YTT. Units assigned to the YTT also occur within the CPC; and the YTT partially encloses and is complexly related to the Intermontane Superterrane (together with the Stikine, Cache Creek, and Quesnel terranes).

Metal mineralization edit

In Alaska (Delta district) and Yukon (Finlayson Lake belt) the YTT contains a number of Devonian volcanogenic massive sulfide ore deposits with significant copper, zinc, lead, silver and gold mineralization. Sulfide minerals include massive to disseminated pyrite and pyrrhotite with lesser amounts of chalcopyrite, galena, sphalerite and arsenopyrite. The deposits show evidence of an Early Cretaceous, amphibolite facies event and a younger, mid-Cretaceous lower greenschist facies event which resulted from the accretion of the Yukon–Tanana Terrane.[9] A belt of significant Late Triassic to Early Jurassic Cu–Au and Cu–Mo porphyry deposits, such as Highland Valley Copper and Galore, of the Stikine Terrane and Quesnel Terrane extends into the Yukon–Tanana Terrane in Yukon; the Minto mine is an example.[10] Gold mineralization associated with post-amalgamation emplacement of Cretaceous and Tertiary plutonic rocks is widespread in the YTT.

References edit

  1. ^ Hansen, V. L.; Dusel-Bacon, C. (1998). "Structural and kinematic evolution of the Yukon–Tanana upland tectonites, east-central Alaska: A record of late Paleozoic to Mesozoic crustal assembly". GSA Bulletin. 110 (2): 211–230. Bibcode:1998GSAB..110..211H. doi:10.1130/0016-7606(1998)110<0211:SAKEOT>2.3.CO;2.
  2. ^ a b Newberry, R. J.; Bundtzen, T. K. (1996). Preliminary geologic map of the Fairbanks mining district, Alaska (PDF) (Report). State of Alaska Department of Natural Resources, Division of Geological & Geophysical Surveys. Retrieved 2 August 2018.
  3. ^ Mihalynuk, M. G.; Nelson, J.; Murphy, D. C.; Brew, D. A.; Erdmer, P.; Hansen, V. L.; Oliver, D. H. (1999). (PDF). GSA Bulletin. 111 (9): 1416–1422. doi:10.1130/0016-7606(1998)110<0211:SAKEOT>2.3.CO;2. S2CID 78312. Archived from the original (PDF) on 2 August 2018. Retrieved 2 August 2018.[clarification needed]
  4. ^ Nelson, J. L.; Mihalynuk, M. G.; Murphy, D. C.; Colpron, M.; Roots, C. F.; Mortensen, J. K.; Friedman, R. M. (1999). Ancient Pacific Margin Part II: A preliminary comparison of potential VMS-hosting successions of Yukon–Tanana Terrane, from Finlayson district to northern British Columbia. Geological Fieldwork. Vol. 2000–1. CiteSeerX 10.1.1.176.4348.
  5. ^ Murphy, D. C. (2006). Late Paleozoic evolution of Yukon–Tanana and Slide Mountain terranes, Finlayson Lake district, southeastern Yukon, Canada. 102nd Annual Meeting of the Cordilleran Section, GSA, 81st Annual Meeting of the Pacific Section, AAPG, and the Western Regional Meeting of the Alaska Section, SPE. Retrieved 2 August 2018.
  6. ^ Dusel-Bacon, C. (2006). Two-Fold Division of Yukon–Tanana Terrane in East-Central Alaska into Parautochthonous and Allochthonous Elements and the Need for Clarification of Terminology. 102nd Annual Meeting of the Cordilleran Section, GSA, 81st Annual Meeting of the Pacific Section, AAPG, and the Western Regional Meeting of the Alaska Section, SPE. Retrieved 2 August 2018.
  7. ^ Hart, C. (2005). "The Geological Framework of the Yukon Territory". Yukon Geology Program Paper. Yukon Geological Survey. CiteSeerX 10.1.1.602.169.
  8. ^ Saltus, R. (2007). Matching Magnetic Trends And Patterns Across The Tintina Fault, Alaska And Canada–Implications For Estimates Of Total Fault Offset. Cordilleran Section: 103rd Annual Meeting (4–6 May 2007). Bellingham, Washington. Retrieved 2 August 2018.
  9. ^ a b Lange, I. M.; Nokleberg, W. J.; Newkirk, S. R.; Aleinikoff, J. N.; Church, S. E.; Krouse, H. R. (1993). "Devonian volcanogenic massive sulfide deposits and occurrences, southern Yukon–Tanana Terrane, eastern Alaska Range, Alaska". Economic Geology. 88 (2): 344–376. doi:10.2113/gsecongeo.88.2.344. Retrieved 2 August 2018.
  10. ^ Tafti, R.; Mortensen, J. K. (2003). Emond, D. S.; Lewis, L. L. (eds.). Early Jurassic porphyry (?) copper (-gold) deposits at Minto and Williams Creek, Carmacks copper belt, western Yukon (Report). Yukon Exploration and Geology. Yukon Geological Survey. pp. 289–303. CiteSeerX 10.1.1.537.2502.

61°49′16″N 141°12′11″W / 61.821°N 141.203°W / 61.821; -141.203

April 08, 2024
yukon, tanana, terrane, tectonic, terrane, that, extends, from, central, alaska, through, central, yukon, into, northern, british, columbia, canada, southeast, alaska, extending, over, 2000, largest, tectonostratigraphic, terrane, northern, north, american, co. The Yukon Tanana Terrane YTT is a tectonic terrane that extends from central Alaska through central Yukon and into northern British Columbia Canada and Southeast Alaska USA Extending over 2000 km the YTT is the largest tectonostratigraphic terrane in the northern North American Cordillera 1 The Yukon Tanana Upland is a physiographic province mostly underlain by rocks of the Yukon Tanana Terrane 2 The Yukon Tanana Terrane yellow stretches across Alaska Yukon and British Columbia Kaltag Tintina fault north of YTT and Denali Fairweather Fault south of YTT in white Understanding and definition of the YTT is constantly progressing the term Yukon Tanana composite terrane or YTCT is used by some workers reflecting the disparate depositional and tectonic histories being recognized in rock units within the YTT 3 Since 2010 some work dispenses altogether with the term Yukon Tanana Terrane in favor of more detailed subdivisions Tectonic history editThe YTT consists of polymetamorphosed and polydeformed metasedimentary metavolcanic and metaplutonic rocks of Upper Paleozoic and older ages that were deposited or emplaced near the edge of the North American continental margin 2 4 Rocks in the terrane record a variety of tectonic settings and have experienced varying amounts of tectonic transport both before and after amalgamation of the YTT with North America Sequences of mainly parautochthonous quartz rich sedimentary rocks derived from the North American continent also include meta igneous rocks with mostly continental geochemical and isotopic signatures Structurally higher sequences contain meta igneous rocks with arc and back arc characteristics The Slide Mountain Seventymile Terrane composed of volcanic rocks typical of seafloor and of typical seafloor sediments is recognized as an ocean basin that divided parts of the YTT before amalgamation of the Yukon Tanana Terrane with the continental margin 5 6 The right lateral strike slip Tintina Fault occurs along the suture zone between the YTT on the south and west and ancestral North America to the east it forms a significant boundary between North America cratonic rocks and rocks of the YTT and associated terranes although displaced continental rocks are found south of the Tintina Fault and pieces of the YTT occur north of the Tintina Fault 7 8 Parts of the YTT have been offset by at least 400 km 250 mi along the Tintina Fault In most of the Alaskan part of the YTT the Denali Fault forms the modern day southern boundary of the terrane 9 In Yukon the ocean basin rocks of the Windy McKinley terrane in western Yukon and the Coast Plutonic Complex CPC form the southern boundary of the YTT Units assigned to the YTT also occur within the CPC and the YTT partially encloses and is complexly related to the Intermontane Superterrane together with the Stikine Cache Creek and Quesnel terranes Metal mineralization editIn Alaska Delta district and Yukon Finlayson Lake belt the YTT contains a number of Devonian volcanogenic massive sulfide ore deposits with significant copper zinc lead silver and gold mineralization Sulfide minerals include massive to disseminated pyrite and pyrrhotite with lesser amounts of chalcopyrite galena sphalerite and arsenopyrite The deposits show evidence of an Early Cretaceous amphibolite facies event and a younger mid Cretaceous lower greenschist facies event which resulted from the accretion of the Yukon Tanana Terrane 9 A belt of significant Late Triassic to Early Jurassic Cu Au and Cu Mo porphyry deposits such as Highland Valley Copper and Galore of the Stikine Terrane and Quesnel Terrane extends into the Yukon Tanana Terrane in Yukon the Minto mine is an example 10 Gold mineralization associated with post amalgamation emplacement of Cretaceous and Tertiary plutonic rocks is widespread in the YTT References edit Hansen V L Dusel Bacon C 1998 Structural and kinematic evolution of the Yukon Tanana upland tectonites east central Alaska A record of late Paleozoic to Mesozoic crustal assembly GSA Bulletin 110 2 211 230 Bibcode 1998GSAB 110 211H doi 10 1130 0016 7606 1998 110 lt 0211 SAKEOT gt 2 3 CO 2 a b Newberry R J Bundtzen T K 1996 Preliminary geologic map of the Fairbanks mining district Alaska PDF Report State of Alaska Department of Natural Resources Division of Geological amp Geophysical Surveys Retrieved 2 August 2018 Mihalynuk M G Nelson J Murphy D C Brew D A Erdmer P Hansen V L Oliver D H 1999 Structural and kinematic evolution of the Yukon Tanana upland tectonites east central Alaska A record of late Paleozoic to Mesozoic crustal assembly Discussion and Reply PDF GSA Bulletin 111 9 1416 1422 doi 10 1130 0016 7606 1998 110 lt 0211 SAKEOT gt 2 3 CO 2 S2CID 78312 Archived from the original PDF on 2 August 2018 Retrieved 2 August 2018 clarification needed Nelson J L Mihalynuk M G Murphy D C Colpron M Roots C F Mortensen J K Friedman R M 1999 Ancient Pacific Margin Part II A preliminary comparison of potential VMS hosting successions of Yukon Tanana Terrane from Finlayson district to northern British Columbia Geological Fieldwork Vol 2000 1 CiteSeerX 10 1 1 176 4348 Murphy D C 2006 Late Paleozoic evolution of Yukon Tanana and Slide Mountain terranes Finlayson Lake district southeastern Yukon Canada 102nd Annual Meeting of the Cordilleran Section GSA 81st Annual Meeting of the Pacific Section AAPG and the Western Regional Meeting of the Alaska Section SPE Retrieved 2 August 2018 Dusel Bacon C 2006 Two Fold Division of Yukon Tanana Terrane in East Central Alaska into Parautochthonous and Allochthonous Elements and the Need for Clarification of Terminology 102nd Annual Meeting of the Cordilleran Section GSA 81st Annual Meeting of the Pacific Section AAPG and the Western Regional Meeting of the Alaska Section SPE Retrieved 2 August 2018 Hart C 2005 The Geological Framework of the Yukon Territory Yukon Geology Program Paper Yukon Geological Survey CiteSeerX 10 1 1 602 169 Saltus R 2007 Matching Magnetic Trends And Patterns Across The Tintina Fault Alaska And Canada Implications For Estimates Of Total Fault Offset Cordilleran Section 103rd Annual Meeting 4 6 May 2007 Bellingham Washington Retrieved 2 August 2018 a b Lange I M Nokleberg W J Newkirk S R Aleinikoff J N Church S E Krouse H R 1993 Devonian volcanogenic massive sulfide deposits and occurrences southern Yukon Tanana Terrane eastern Alaska Range Alaska Economic Geology 88 2 344 376 doi 10 2113 gsecongeo 88 2 344 Retrieved 2 August 2018 Tafti R Mortensen J K 2003 Emond D S Lewis L L eds Early Jurassic porphyry copper gold deposits at Minto and Williams Creek Carmacks copper belt western Yukon Report Yukon Exploration and Geology Yukon Geological Survey pp 289 303 CiteSeerX 10 1 1 537 2502 61 49 16 N 141 12 11 W 61 821 N 141 203 W 61 821 141 203 Retrieved from https en wikipedia org w index php title Yukon Tanana Terrane amp oldid 1181943681, wikipedia, wiki, book, books, library,

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