At www.sciencedaily.com/releases/2010/07/100726144011.htm there is a new intepretation of the Banda Arc, a giant 1000km long 180 degree curve in eastern Indonesia which has never been adequately explained. In fact, there has been considerable controversy about how to explain the feature – its origin and evolution. A paper in Nature Geoscience sets out to do just that, using a computer simulation or model. The Banda Arc sits at the crossroads of three converging plates and is apparently a youngish feature, a piece of oceanic crust enclosed by a volcanic inner arc, outer arc islands, and a trough parallel to the Australian plate margin. It is a complex subduction region as one plate moves under another – and three of them are pushing against each other. The situation is actually quite perfect for a computer generated explanation as the possibilities are limited and assumptions are not made. The model is also able to throw light on how mountains form as the Banda Arc is in effect a youthful mountain range in the making.
At http://geology.com/usgs/geologic-time-scale/ there is a new geological chronology that has just been accepted by a range of different countries. The graph or timetable can be downloaded as a reference tool.