The origin of our wide brown land 

Over the last 6 months, ​I have been reading and reflecting on our big Australian journey last year and want to see more!  The origin of our wide brown land and its geological relationship with the rest of the world, is quite compelling and absorbing - I wish I knew more! But to start somewhere in the distance past closer to our origins, we need to fast-rewind over 3 billion years to the time when oxygen and photosynthesis was just dawning during the Archaean era, the time of the Supercontinent of Ur, a time when there was probably only one land mass.

That supercontinent broke apart but not surprisingly, important geomorphic similarities now link remote Archaean cratons across the world. Cratons are chunks of that almost mythical continent of Ur and they still exist in India, Australia, and Southern Africa. In Australia there are 3 cratonic shields:

*the Pilbara, where we walked on and among fragments of that ancient crust,

*the Yilgarn which comprises a large part of central, southern WA and is Australia’s premier mineral province through which we travelled last year, and

*the Gawler craton in SA. I love that region , it’s like stepping back to a time forgotten, a place you could happily lose yourself in.

Among the tumbled piles of broken pieces of the earth's crust and etched onto the face of those rocks are 1000s of images 10s of 1000s of years old. They represent the highest concentration of rock carving in the world. Murujuga NP on the Burrup peninsula, in the Pilbarra 

All these areas are extraordinarily ancient and very rich in precious ores and minerals - and of course as a result have been and continue to be exploited for economic gain.

From the time of the Land of Ur fast-forward through alternating ice and greenhouse ages to now when we are slipping into another greenhouse epoch (with loads of astonishing geological feats in between - sorry, space, ignorance and all that) and the jigsaw, mosaic of continents sitting astride a number of tectonic plates (which are either converging or diverging in relation to each other).

Australia is part of the Indo-Australian Plate. There is some suggestion this large Plate separated over 3 million years ago with Australia now moving northward at a rate of 5.6cm per year further into the tropics. We were connected. And the Indo plate moved north crushing into the Eurasian plate - and voila! the Himalayas were formed and continue to grow a few cm per year so that plate is still moving. Compared to Australia cratons this is very new. It is all fascinating however ..... what is exciting to me - well one of many things!!-  are the places where those earth-crust (tectonic) plates meet and what results. Think the specific Ring of Fire and the Himalayas and beyond! Many of those intersections we are yet to explore/learn about - life seems too short!
We sailed along the northern edge of the Pacific Tectonic Plate west and south through the Commander and Kuril Islands 2 years ago and saw where volcanoes trace the plate edge. Having seen the effects of convergence with other plates around the Pacific Ring of Fire, I am currently looking to where the once Indo-Australian Tectonic Plate converged with and crumpled the southern edge of the Eurasian Plate creating a huge mountainous region and vast basins and deserts some areas below sea level. There is not the same volcanic activity in this mighty land seam as there is on the pacific Eurasian convergence, but there are earthquakes. But of particular interest to me is that this region is not so far south, globally speaking, of where we will be travelling along the age-old Central Asian trade route, the Silk Road, in just a month. I am so excited!
I've been studying up on the area and feel a little overloaded. The geographical as well as cultural history of this Central Asian region is mind blowing. Over the millennia people, conquerors, cultures, religions, merchandise and ideas have  traversed the region's steppes, vast arid deserts and mountain passes.  The peoples and cultures are ages old - Persians, Arabs, Uyghur, and there is genetic evidence of people from the far west having once lived or at least visited in the region, Alexander the Great for one and there is genetic evidence of caucasoid ancestry; I will be visiting the Urumqi museum which houses the mummified remains which gives visible evidence of this.

So much to know about this amazing world of ours it would take a few lifetimes to discover and write about it. So I have to content myself with snippets from my own meager discoveries - but it is not a comfortable space for me having to be content with unanswered questions. But there you are ..........
I will keep you posted along the way as I learn more.