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

Research output: Chapter in Book/Report/Conference proceedingChapter in bookResearchpeer-review

11 Citations (Scopus)

Abstract

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.

Original languageEnglish
Title of host publicationVertical coupling and decoupling in the lithosphere
EditorsJ. Grocott, K.J.W. McCaffrey, G. Taylor, B. Tikoff
Place of PublicationLondon, United Kingdom
PublisherGeological Society of London
Pages231-248
Number of pages18
ISBN (Print)1-86239-159-9
DOIs
Publication statusPublished - 2004

Publication series

NameGeological Society Special Publications (London)
PublisherGeological Society of London
Volume227

Programme Area

  • Programme Area 4: Mineral Resources

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