BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//talks.cam.ac.uk//v3//EN
BEGIN:VTIMEZONE
TZID:Europe/London
BEGIN:DAYLIGHT
TZOFFSETFROM:+0000
TZOFFSETTO:+0100
TZNAME:BST
DTSTART:19700329T010000
RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=-1SU
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:+0100
TZOFFSETTO:+0000
TZNAME:GMT
DTSTART:19701025T020000
RRULE:FREQ=YEARLY;BYMONTH=10;BYDAY=-1SU
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
CATEGORIES:Department of Earth Sciences Seminars (downtown)
SUMMARY:Active plate tectonics in the Paleoarchean - Simon
  Lamb\, Victoria University of Wellington
DTSTART;TZID=Europe/London:20241029T120000
DTEND;TZID=Europe/London:20241029T130000
UID:TALK220474AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/220474
DESCRIPTION:Plate tectonics has played a major role in the Ear
 th’s evolution\, both in the cooling of the planet
 ary interior\, and\, it is widely argued\, the mai
 ntenance of liquid water and life at the surface. 
 But was the Earth always like this? The answer to 
 this question is most likely to lie in relicts of 
 the early Earth’s surface\, preserved in Archean g
 reenstone belts and found in almost all the craton
 s. In this talk\, I compare field relations in the
  3.5 – 3.2 Ga Barberton Greenstone Belt in South A
 frica and Eswatini with the active New Zealand sub
 ducting plate-boundary zone. I show that there are
  remarkable similarities in structure and stratigr
 aphy\, with many of the distinctive features of co
 nvergent plate margins\, and I argue that the simp
 lest explanation is that plate tectonics was fully
  active in the Paleoarchean\, generating great ear
 thquakes on the subduction megathrust and growth f
 olds and major low angle thrusts in the overlying 
 accretionary prism and subsequent continental coll
 ision. \n\nOceania in the SW Pacific may provide u
 s with the closest modern example of the surface o
 f the Paleoarchean Earth\, forming a water world w
 ith active volcanoes\, back-arc spreading and smal
 l continental landmasses along a subducting plate 
 boundary with local continental collision. In fact
 \, the eruption of boninites here in the back-arc 
 region may be a direct analogy for the typical kom
 atiitic volcanism in the early Earth. The explosiv
 e eruption of Hunga Volcano near Tonga in 2022 cou
 ld even provide clues to the origin of life\, sugg
 esting that life was born out of the extreme viole
 nce of plate tectonics\, a far cry from Darwin’s b
 enign and warm little pond!\n
LOCATION:Department of Earth Sciences\, Tilley Lecture Thea
 tre
CONTACT:Dr Rachael Rhodes
END:VEVENT
END:VCALENDAR