Meso- and Neoarchaean geological history of the Bjørnesund and Ravns Storø Supracrustal Belts, southern West Greenland: settings for gold enrichment and corundum formation

Nynke Keulen; John C. Schumacher; Tomas Næraa; Thomas F. Kokfelt; Anders Scherstén; Kristoffer Szilas; Vincent J. van Hinsberg; Denis M. Schlatter; Brian F. Windley

doi:10.1016/j.precamres.2014.07.023

Meso- and Neoarchaean geological history of the Bjørnesund and Ravns Storø Supracrustal Belts, southern West Greenland: settings for gold enrichment and corundum formation

Nynke Keulen, John C. Schumacher, Tomas Næraa, Thomas F. Kokfelt, Anders Scherstén, Kristoffer Szilas, Vincent J. van Hinsberg, Denis M. Schlatter, Brian F. Windley

21 Citationer (Scopus)

Abstract

To understand the Meso- and Neoarchaean geological history of the Bjørnesund region, southern West Greenland (ca. 62-63° N), we have undertaken an integrated study combining field observations with U-Pb zircon geochronology by LA-ICP-MS, metamorphic petrology, and microstructural analyses. The Bjørnesund region links the southern part of the Fiskenæsset anorthosite complex to the well-preserved metavolcanic rocks of the Ravn Storø Supracrustal Belt and the Bjørnesund Supracrustal Belt, so the development of this region is of key interest to unravelling the Archaean geology of the entire region. In this study, we couple the observed phases of gold-enrichment and corundum formation to the geological history.The leucogabbroic rocks of the Bjørnesund region, which are part of the Fiskenæsset complex, intruded at ca. 2.95. Ga into the tholeiitic and calc-alkaline metavolcanic rocks of the two studied belts. Following isoclinal folding, the rocks were intruded by diorite (2.92. Ga) and granodiorite (2.91 and 2.88. Ga), which are now texturally orthogneisses. The area was affected by three major phases of folding; F1 (undated), F2 at 2.85-2.83. Ga, and F3 at 2.71-2.70. Ga. The former deformation event is associated with the gold-enrichment in alteration zones in shear folds in metavolcanic amphibolite near the contact with the orthogneiss. Intrusion of granitic sheets during the F3 deformation triggered the formation of corundum, which is locally of gem quality, at the contact between leucogabbroic and ultramafic rocks. Peak metamorphic conditions were calculated as 580-630. °C and 6-4. kbar at 2.85-2.83. Ga. Later retrogression in the southern part of the area at ca. 500-450. °C and 4.5-3. kbar, and extensional fault reactivation overprinted some of the older structures.

Originalsprog	Engelsk
Tidsskrift	Precambrian Research
Vol/bind	245
Sider (fra-til)	36-58
Antal sider	23
ISSN	0301-9268
DOI	https://doi.org/10.1016/j.precamres.2014.07.023
Status	Udgivet - nov. 2014
Udgivet eksternt	Ja

Adgang til dokumentet

10.1016/j.precamres.2014.07.023

Citationsformater

Keulen, N., C. Schumacher, J., Næraa, T., Kokfelt, T. F., Scherstén, A., Szilas, K., van Hinsberg, V. J., Schlatter, D. M., & Windley, B. F. (2014). Meso- and Neoarchaean geological history of the Bjørnesund and Ravns Storø Supracrustal Belts, southern West Greenland: settings for gold enrichment and corundum formation. Precambrian Research, 245, 36-58. https://doi.org/10.1016/j.precamres.2014.07.023

Meso- and Neoarchaean geological history of the Bjørnesund and Ravns Storø Supracrustal Belts, southern West Greenland : settings for gold enrichment and corundum formation. / Keulen, Nynke; C. Schumacher, John; Næraa, Tomas et al.

I: Precambrian Research, Bind 245, 11.2014, s. 36-58.

Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › peer review

Keulen, N, C. Schumacher, J, Næraa, T, Kokfelt, TF, Scherstén, A, Szilas, K, van Hinsberg, VJ, Schlatter, DM & Windley, BF 2014, 'Meso- and Neoarchaean geological history of the Bjørnesund and Ravns Storø Supracrustal Belts, southern West Greenland: settings for gold enrichment and corundum formation', Precambrian Research, bind 245, s. 36-58. https://doi.org/10.1016/j.precamres.2014.07.023

@article{8d3f5f2be58e4658999fdeb04bfeb9b1,

title = "Meso- and Neoarchaean geological history of the Bj{\o}rnesund and Ravns Stor{\o} Supracrustal Belts, southern West Greenland: settings for gold enrichment and corundum formation",

abstract = "To understand the Meso- and Neoarchaean geological history of the Bj{\o}rnesund region, southern West Greenland (ca. 62-63° N), we have undertaken an integrated study combining field observations with U-Pb zircon geochronology by LA-ICP-MS, metamorphic petrology, and microstructural analyses. The Bj{\o}rnesund region links the southern part of the Fisken{\ae}sset anorthosite complex to the well-preserved metavolcanic rocks of the Ravn Stor{\o} Supracrustal Belt and the Bj{\o}rnesund Supracrustal Belt, so the development of this region is of key interest to unravelling the Archaean geology of the entire region. In this study, we couple the observed phases of gold-enrichment and corundum formation to the geological history.The leucogabbroic rocks of the Bj{\o}rnesund region, which are part of the Fisken{\ae}sset complex, intruded at ca. 2.95. Ga into the tholeiitic and calc-alkaline metavolcanic rocks of the two studied belts. Following isoclinal folding, the rocks were intruded by diorite (2.92. Ga) and granodiorite (2.91 and 2.88. Ga), which are now texturally orthogneisses. The area was affected by three major phases of folding; F1 (undated), F2 at 2.85-2.83. Ga, and F3 at 2.71-2.70. Ga. The former deformation event is associated with the gold-enrichment in alteration zones in shear folds in metavolcanic amphibolite near the contact with the orthogneiss. Intrusion of granitic sheets during the F3 deformation triggered the formation of corundum, which is locally of gem quality, at the contact between leucogabbroic and ultramafic rocks. Peak metamorphic conditions were calculated as 580-630. °C and 6-4. kbar at 2.85-2.83. Ga. Later retrogression in the southern part of the area at ca. 500-450. °C and 4.5-3. kbar, and extensional fault reactivation overprinted some of the older structures.",

author = "Nynke Keulen and {C. Schumacher}, John and Tomas N{\ae}raa and Kokfelt, {Thomas F.} and Anders Scherst{\'e}n and Kristoffer Szilas and {van Hinsberg}, {Vincent J.} and Schlatter, {Denis M.} and Windley, {Brian F.}",

year = "2014",

month = nov,

doi = "10.1016/j.precamres.2014.07.023",

language = "English",

volume = "245",

pages = "36--58",

journal = "Precambrian Research",

issn = "0301-9268",

publisher = "Elsevier",

}

TY - JOUR

T1 - Meso- and Neoarchaean geological history of the Bjørnesund and Ravns Storø Supracrustal Belts, southern West Greenland

T2 - settings for gold enrichment and corundum formation

AU - Keulen, Nynke

AU - C. Schumacher, John

AU - Næraa, Tomas

AU - Kokfelt, Thomas F.

AU - Scherstén, Anders

AU - Szilas, Kristoffer

AU - van Hinsberg, Vincent J.

AU - Schlatter, Denis M.

AU - Windley, Brian F.

PY - 2014/11

Y1 - 2014/11

N2 - To understand the Meso- and Neoarchaean geological history of the Bjørnesund region, southern West Greenland (ca. 62-63° N), we have undertaken an integrated study combining field observations with U-Pb zircon geochronology by LA-ICP-MS, metamorphic petrology, and microstructural analyses. The Bjørnesund region links the southern part of the Fiskenæsset anorthosite complex to the well-preserved metavolcanic rocks of the Ravn Storø Supracrustal Belt and the Bjørnesund Supracrustal Belt, so the development of this region is of key interest to unravelling the Archaean geology of the entire region. In this study, we couple the observed phases of gold-enrichment and corundum formation to the geological history.The leucogabbroic rocks of the Bjørnesund region, which are part of the Fiskenæsset complex, intruded at ca. 2.95. Ga into the tholeiitic and calc-alkaline metavolcanic rocks of the two studied belts. Following isoclinal folding, the rocks were intruded by diorite (2.92. Ga) and granodiorite (2.91 and 2.88. Ga), which are now texturally orthogneisses. The area was affected by three major phases of folding; F1 (undated), F2 at 2.85-2.83. Ga, and F3 at 2.71-2.70. Ga. The former deformation event is associated with the gold-enrichment in alteration zones in shear folds in metavolcanic amphibolite near the contact with the orthogneiss. Intrusion of granitic sheets during the F3 deformation triggered the formation of corundum, which is locally of gem quality, at the contact between leucogabbroic and ultramafic rocks. Peak metamorphic conditions were calculated as 580-630. °C and 6-4. kbar at 2.85-2.83. Ga. Later retrogression in the southern part of the area at ca. 500-450. °C and 4.5-3. kbar, and extensional fault reactivation overprinted some of the older structures.

AB - To understand the Meso- and Neoarchaean geological history of the Bjørnesund region, southern West Greenland (ca. 62-63° N), we have undertaken an integrated study combining field observations with U-Pb zircon geochronology by LA-ICP-MS, metamorphic petrology, and microstructural analyses. The Bjørnesund region links the southern part of the Fiskenæsset anorthosite complex to the well-preserved metavolcanic rocks of the Ravn Storø Supracrustal Belt and the Bjørnesund Supracrustal Belt, so the development of this region is of key interest to unravelling the Archaean geology of the entire region. In this study, we couple the observed phases of gold-enrichment and corundum formation to the geological history.The leucogabbroic rocks of the Bjørnesund region, which are part of the Fiskenæsset complex, intruded at ca. 2.95. Ga into the tholeiitic and calc-alkaline metavolcanic rocks of the two studied belts. Following isoclinal folding, the rocks were intruded by diorite (2.92. Ga) and granodiorite (2.91 and 2.88. Ga), which are now texturally orthogneisses. The area was affected by three major phases of folding; F1 (undated), F2 at 2.85-2.83. Ga, and F3 at 2.71-2.70. Ga. The former deformation event is associated with the gold-enrichment in alteration zones in shear folds in metavolcanic amphibolite near the contact with the orthogneiss. Intrusion of granitic sheets during the F3 deformation triggered the formation of corundum, which is locally of gem quality, at the contact between leucogabbroic and ultramafic rocks. Peak metamorphic conditions were calculated as 580-630. °C and 6-4. kbar at 2.85-2.83. Ga. Later retrogression in the southern part of the area at ca. 500-450. °C and 4.5-3. kbar, and extensional fault reactivation overprinted some of the older structures.

U2 - 10.1016/j.precamres.2014.07.023

DO - 10.1016/j.precamres.2014.07.023

M3 - Journal article

SN - 0301-9268

VL - 245

SP - 36

EP - 58

JO - Precambrian Research

JF - Precambrian Research

ER -

Meso- and Neoarchaean geological history of the Bjørnesund and Ravns Storø Supracrustal Belts, southern West Greenland: settings for gold enrichment and corundum formation

Abstract

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