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Folding of angular unconformable sequences and effects on early folds, Tabberabbera district, eastern Victoria, Australia

Journal Article


Abstract


  • The Tabberabbera district of the southeast Lachlan Fold Belt has a good example of a complex fold pattern produced by folding of angular unconformable sequences. Ordovician quartz flysch (Hotham Group) contains subhorizontal, upright, tight, easterly trending F1 folds of Early to Middle Silurian age. These have been reoriented by a locally intense Middle Devonian deformation that has formed an upright isoclinal syncline (Mitchell syncline) in the unconformably overlying Emsian clastic sequence (Wentworth Group). Many of the F1 folds in the Hotham Group immediately west of the Mitchell syncline have steep northwest trending axial surfaces and are steeply plunging. East of the syncline F1 folds are upright, with shallow plunges, and gradually become inclined to recumbent as the unconformity is approached. A folded foam-layer analogue matching the geometry of the Mitchell syncline shows that the reorientation of early fold axes and axial surfaces produced by the unconformity-folding event is identical to that predicted by the model. �� 1989.

Publication Date


  • 1989

Citation


  • Fergusson, C. L., & Gray, D. R. (1989). Folding of angular unconformable sequences and effects on early folds, Tabberabbera district, eastern Victoria, Australia. Tectonophysics, 158(1-4). doi:10.1016/0040-1951(89)90318-1

Scopus Eid


  • 2-s2.0-0024534496

Volume


  • 158

Issue


  • 1-4

Place Of Publication


Abstract


  • The Tabberabbera district of the southeast Lachlan Fold Belt has a good example of a complex fold pattern produced by folding of angular unconformable sequences. Ordovician quartz flysch (Hotham Group) contains subhorizontal, upright, tight, easterly trending F1 folds of Early to Middle Silurian age. These have been reoriented by a locally intense Middle Devonian deformation that has formed an upright isoclinal syncline (Mitchell syncline) in the unconformably overlying Emsian clastic sequence (Wentworth Group). Many of the F1 folds in the Hotham Group immediately west of the Mitchell syncline have steep northwest trending axial surfaces and are steeply plunging. East of the syncline F1 folds are upright, with shallow plunges, and gradually become inclined to recumbent as the unconformity is approached. A folded foam-layer analogue matching the geometry of the Mitchell syncline shows that the reorientation of early fold axes and axial surfaces produced by the unconformity-folding event is identical to that predicted by the model. �� 1989.

Publication Date


  • 1989

Citation


  • Fergusson, C. L., & Gray, D. R. (1989). Folding of angular unconformable sequences and effects on early folds, Tabberabbera district, eastern Victoria, Australia. Tectonophysics, 158(1-4). doi:10.1016/0040-1951(89)90318-1

Scopus Eid


  • 2-s2.0-0024534496

Volume


  • 158

Issue


  • 1-4

Place Of Publication