Attachment formation during partitioning of oblique convergence in the Ketilidian orogen, south Greenland

K.J.W. McCaffrey, J. Grocott, A.A. Garde, M.A. Hamilton

Publikation: Bidrag til bog/rapport/konferenceproceedingsBogkapitelForskningpeer review

11 Citationer (Scopus)

Abstrakt

Subhorizontal attachment zones provide coupling between lithospheric layers in orogenic belts. A mid-crustal attachment zone is exposed in the Palaeoproterozoic Ketilidian orogen, south Greenland, which formed as a result of north-directed oblique convergence at a cordilleran-type margin. Rifting (c. 2.1 Ga) and compressional deformation and magmatism (>1850 Ma) on the continental margin was followed by an extended sinistral transpression from 1850 to 1730 Ma now separated into three episodes or peaks of activity. The first episode was focused on the back-arc region and was followed by the main arc construction phase during which transpression was partitioned into strike-slip and contraction components. Despite the longevity of this active margin system, individual tectonic events took place rapidly, e.g. development of fore-arc D 1-D 3 and accompanying high-temperature, low-pressure metamorphism took place over c. 12 Ma. We explain the fore-arc and batholith evolution by the upward migration of an underlying attachment structure through the upper crustal partitioned blocks. This migration may be attributed to an increase in the geothermal gradient accompanied by, or followed by, exhumation of the mid-crust. The partially molten, hence weak, attachment zone solidified and strengthened during cooling before emplacement of the post-orogenic rapakivi suite during the third distinct phase of mild sinistral transpression.

OriginalsprogEngelsk
TitelVertical coupling and decoupling in the lithosphere
RedaktørerJ. Grocott, K.J.W. McCaffrey, G. Taylor, B. Tikoff
UdgivelsesstedLondon, United Kingdom
ForlagGeological Society of London
Sider231-248
Antal sider18
ISBN (Trykt)1-86239-159-9
DOI
StatusUdgivet - 2004

Publikationsserier

NavnGeological Society Special Publications (London)
ForlagGeological Society of London
Vol/bind227

Programområde

  • Programområde 4: Mineralske råstoffer

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