BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//CERN//INDICO//EN
BEGIN:VEVENT
SUMMARY:Structural deformation features of the Bokkeveld Group (Cape Super
 group) in the Eastern Cape\, South Africa
DTSTART;VALUE=DATE-TIME:20141003T070000Z
DTEND;VALUE=DATE-TIME:20141003T071500Z
DTSTAMP;VALUE=DATE-TIME:20261006T160316Z
UID:indico-contribution-3991@events.saip.org.za
DESCRIPTION:Speakers: Gideon Brunsdon (Nelson Mandela Metropolitan Univers
 ity)\nPrevious studies of the Bokkeveld Group focussed mostly on the sedim
 entation and sedimentary features of this group with a view to interpretin
 g the depositional environment.  This study aims to contribute new informa
 tion on the structural features of the Bokkeveld Group north-west of Uiten
 hage in the Eastern Cape\, where there is evidence of folding and pervasiv
 e thrust faulting\, similar to that occurring in the under- and overlying 
 groups of the Cape Supergroup. \nField work to date shows that predominant
 ly argillaceous units comprising siltstones\, mudstones\, with lesser aren
 ites and thin conglomerate beds making up the Bokkeveld Group conformably 
 overly the Table Mountain Group of predominantly arenaceous beds. Both gro
 ups have been folded into asymmetric anticlines and synclines\, with a pro
 minent\, south-dipping pervasive cleavage developed in the Bokkeveld Group
 . The fissile nature of argillaceous beds on outcrop have required that ve
 ry careful observations of the all important bedding-cleavage relationship
  in the field are made so that correct interpretations of facing direction
  of strata can be applied.  Thrust faults showing fore-and backthrusts are
  present in the Bokkeveld Group\, similar to those occurring in the overly
 ing Witteberg Group. These structures are interpreted to have formed durin
 g a main deformation phase of the Cape Orogeny\, during the Permian. \nIn 
 places structural orientation data indicate that bedding planes dip predom
 inantly to the Northeast and to the Southwest.  Cleavage dips consistently
  to the Southeast\, although the dip of the cleavage varies from steeper t
 o less steep in different formations.  A section studies along the Hottent
 otspoort road revealed that the more arenaceous beds often display folding
  as the main structural feature\, whilst the argillaceous layers display m
 ore faulting and small scale folding.  Faulting is present throughout the 
 whole section\, mostly in the form of south-southwest dipping reverse faul
 ts and shallow dipping thrust faults.  Strike-slip faulting has also been 
 recorded.  Flexure-slip faults occur mainly in the more arenaceous units a
 nd are associated with large scale folding in the area.\nThis study so far
  indicates that structural characteristics of the Bokkeveld Group have bee
 n identified on macro and microscopic scale\, and detailed analyses of the
 se structures should reveal valuable information with regard to the deform
 ational history of these rocks.  In the field cleavages may easily be mist
 aken for bedding and this relationship needs to be carefully verified thro
 ugh microscopic studies. A significant emphasis is placed on this aspect t
 o avoid incorrect interpretations in the field. The results of this study 
 will inevitably point to the fact that strata have been disrupted by struc
 tures such as folds and thrust faults to the extent that the stratigraphic
  order of the Bokkeveld Group in this area will have to be re-assessed.\n\
 nhttps://events.saip.org.za/event/40/contributions/3991/
LOCATION:Matjiesfontein's Lord Milner Hotel Conference Room\, Matjiesfonte
 in Station
URL:https://events.saip.org.za/event/40/contributions/3991/
END:VEVENT
END:VCALENDAR