A view from the roof: Magmatic stoping in the shallow crust, Chita pluton, Argentina

Aaron S. Yoshinobu, T. Kenneth Fowler, Scott R. Paterson, Eduardo Llambias, Hugo Tickyj, Ana Maria Sato

Research output: Contribution to journalArticle

37 Scopus citations

Abstract

Nearly 2 km of vertical relief and exposure of continuous pluton roof-wall corners around the Chita pluton, northwest Argentina, provides constraints on the 3-D host rock displacement field attending magma emplacement in the shallow crust. The pluton is rectangular in cross-sectional view and consists of weakly to non-deformed granite to granodiorite. Structures in surrounding metasedimentary host rocks are truncated at a knife-sharp contact and are only weakly deflected from their regional orientations. Final emplacement occurred by stoping together with minor doming of the earth's surface. Structural restoration of a cross-section indicates that host-rocks above the pluton may have been domed upwards during emplacement by as much as a few hundred meters, accounting for up to 20% of the exposed pluton volume. The remaining 80% of the space for pluton emplacement was made by downward removal of host-rock from the present level of exposure. Although mechanisms such as floor-subsidence are permissive, late stoping has destroyed evidence for the early emplacement history. However, geometrical constraints provided by exposure of continuous wall-to-roof contacts indicate that early emplacement mechanisms at this level in the crust and immediately below were also dominated by the downward displacement of host rocks through a conduit that now is represented by the solidified pluton.

Original languageEnglish
Pages (from-to)1037-1048
Number of pages12
JournalJournal of Structural Geology
Volume25
Issue number7
DOIs
StatePublished - Jul 2003

Keywords

  • Argentina Frontal Cordillera
  • Granite
  • Magmatic arcs
  • Pluton emplacement
  • Stoping

Fingerprint Dive into the research topics of 'A view from the roof: Magmatic stoping in the shallow crust, Chita pluton, Argentina'. Together they form a unique fingerprint.

Cite this