How geological processes formed Marble Bar

From Pilbara

Jump to: navigation, search


This is a transcript of a QuickTime movie (4.9 MB) recorded in the Pilbara in 2005. Dr Martin Van Kranendonk, a geologist with the Geological Survey of Western Australia, introduces field trip participants to the geological processes that formed the Marble Bar area.


Everything took a really long time in the Pilbara to get to the present geometry. There is a lot of Earth history here and so when I say doming I mean many punctuated events over that period of time. And it just shows simply here, but there are actually multiple phases of granites, that doming occurred once, twice, three, four, five times. And then with the granite doming they all got pushed up on their side and here they’re actually overturned. And so we’re going to be walking and you’ll see the rocks dipping under your feet this way. That’s the way that they’ve been pushed over but I’ll show you evidence to show that those basalts are actually pointing down into the ground now. The tops of the basalts are pointing down into the ground. So you can see that those rocks have been tilted over and those are like the fundamental things we do as geologists. We try to reconstruct environments based on what we map on the ground. So a little bit of today is for that kind of teaching role for those of you who have not been on outcrops before. We’ll try and convince you that you can actually look at texture in rock and make some meaningful conclusions from it. We’re all not just arm wavers. And then we’ll go and get a bit more into it on the Marble Bar chert about process of chert formation, which many of the more learned people here are interested in.




Early Life



Personal tools