Earth Learning Idea

I have recently come across an interesting and easy to understand site that explains earth processes in fun and creative ways. This is a site called Earth Learning Idea. By way of examples here is a demonstration of sink holes that you can try yourself (just like those I mention in the addendum to this earlier blog post):
http://www.earthlearningidea.com/PDF/185_Sink_hole.pdf.

I'm pleased to see such an interesting site. It made me wonder whether I should be more pro-active in earth science education. Recently helping to sort out a rock collection for a local environmental centre is something that I enjoyed. I've also been honoured by an invitation to do a formal presentation at this years Big Scrub Rainforest Day. I'm happy to do these things because I enjoy geology and I enjoy talking with people.

Interestingly, as a member of the Geological Society of Australia I can be more formally aligned with geology education by joining the Specialist Group in Geological Education. I just don't want to stretch myself too far as I'm already a member of three specialist groups: the Environmental Engineering and Hydrogeology Specialist Group, Specialist Group in Geochemisty, Mineralogy and Petrology and the Specialist Group in Vocanology (Learned Australasian Volcanology Association). I have another 6 months to decide... I think it is good to take time in making decision... even if this is a little one.

Blog Update #5

It has been about a year since my last blog update. I'm pleased with how well the blog is ticking along though I've been a bit slow in posting sometimes and I am still neglecting many areas. The area between Camden Haven and Coffs Harbour is regularly neglected, so too the New England highlands. I also tend to leave at least one typo per post! Not for the first time I will try and remedy these issues in future posts.

The next few months will have a focus on several areas:

• Continuing on the hydrogeology theme;
• Points of interest in the Macleay River catchment;
• The Mount Warning Central Complex;
• Recent reviews of the upper stratigraphy of the Clarence-Moreton Basin;
• Some more posts on gas resources; and
• A granite intrusion or two in the New England tablelands

While I'm looking both backward and forward. I'm looking forward to reaching 100 000 page views in the next few months. At the time of this post there were over 85 000 views though I estimate approximately 20% of these are not human visitors.

I'm also looking forward to the pocket money this blog is now helping me with. Visitors will notice advertising in the top right corner of the page. When visitors click on these ads I receive between 1cent and 80cents from Google. These ads are not ones that I choose but are placed by Google Adsense based upon the content of this page and your own Google search history. So far I've noticed ads for fracking companies, TAFE and universities and even Clive Palmers Australia Party! I've had advertising for about 2 months now and I've made enough for about 4 cups of coffee. How exciting!

Thanks to everyone for continuing to visit and comment. I appreciate comments and try to respond to all of them.

This is what one aquifer looks like

In some amazing places you can immerse yourself in an aquifer. These places are rare and dominated by a rock type that does not occur in any substantial amounts in our region. However, people dive in the sub-terrainian waters of the limestone caves of the Nullabour in South Australia. The best aquifers in our region do not contain large caves compared with limestone areas. They are hosted in riverine alluvial sediments, fossil soil horizons in volcanic rocks, or fractures in hard metamorphic and volcanic environments. The main aquifers being on the coastal river flood plains, Alstonville Basalt and the New England areas respectively. However, volumetrically the sources that are very large are those in coastal sands.

Auger containing saturated sand from the Woodburn Sands

This post is an illustration of how one of those coastal sands aquifers looks. I've covered the Woodburn Sands in several previous posts but a quick summary is still needed. The Woodburn Sands are beach and dune sand that was laid down during the last significant interglacial. This was around 130 000 years ago during the Pleistocene period. The sea level was much higher than now and this meant that beach systems were often formed a significant way inland.

From the picture you can actually see what the medium that hosts an aquifer looks like. The Woodburn Sands are just that, sands. The sand grains are mostly quartz but there are also some grains made from volcanic and metamorphic rock fragments. Occasionally you can see grains of heavier minerals that were mined until the 1980's. The sand grains are very similar in size which is typical of wave and wind sorting. There is a very small fine fraction of clayey material.

Where the clay content is higher the ability of the water to flow through the aquifer is reduced. This is why some bores can only produce a small amount of water compared to the huge volume that is in the whole aquifer. This is an example of why aquifers tend not to behave as underground lakes. You can pump water out of one end and run out because the hydraulic conductivity (flow velocity) is not high enough to allow the water at the other end of the aquifer to flow in.

The Woodburn Sands is not the only important coastal sands aquifer in the region. Another very important water source include the Macleay sand coastal aquifers. These aquifers were formed in a similar way to the Woodburn Sands and are used for similar purposes. Usage includes irrigation, stock, domestic use and town water supply for places such as Kempsey and Evans Head. There are also some interesting arsenic contamination issues in one aquifer system (Stuarts Point) in the Macleay area which I will post on in the near future.

The similar characteristics of the coastal sands aquifer systems in the North Coast area has motivated the NSW state government to develop a Water Sharing Plan for these systems as a whole. The Water Sharing Plan is expected to be formally adopted this year (2014). Local governments regard groundwater from the coastal sands aquifers as very important. Rous Water has recently adopted its future water strategy which identifies coastal sands as the main source of additional information in the medium to long term and Mid-coast water have recently increased their production of groundwater for drinking too.

Available here is a presentation by the NSW Office of Water on the overall coastal sands systems in North East New South Wales

Geology, stratigraphy, water and CSG a bit more understood

A CSIRO researcher recently provided me with a copy of a conference paper on the Clarence-Moreton Basin that I have been searching for (Doig & Stanmore 2012). I was looking for this information for quite some time as I thought there was much to be learned from it. This is because the research was based upon coal seam gas (CSG) exploration results. It did not disappoint me at all. I have previously blogged on the stratigraphy of the basin but frequent visitors will be aware that there has been a hiatus on this topic. This is because I knew more information had been compiled as a result of gas exploration in the region. In particular this was to do with the Grafton Formation and Kangaroo Creek Sandstone. You can read my previous posts but note that Doig & Stanmore (2012) propose to reclassify these units (see figures 1 and 2 on this post). The information my previous posts were based upon Wells and O’Brien (1994). This is still the most comprehensive guide to the basin but now there is potentially some significant refinements.

Interpretation of the stratigraphy of the upper sequences of the Clarence-Moreton Basin
after Wells & O'Brien (1994) and Willis (1994)

Doig & Stanmore (2012) noted that CSG exploration drilling has provided important clues to the layers that make up the Clarence-Moreton basin that were inferred only through limited field exposure. Drilling provides a nice continuous profile which can be compared to other drill holes and to outcropping information. In the case of Doig & Stanmore (2012) this has completely redrawn the stratigraphy of the upper Clarence-Moreton Basin.

Reviewed Clarence-Moreton Basin stratigraphy after Doig & Stanmore (2012)

I will go into more detail in future posts but I note that Doig & Stanmore (2012) have made some major changes to the Grafton Formation. In particular, they have identified two new distinct members of the formation. The Piora Member and the Rappville Member. As for the underlying Kangaroo Creek Sandstone, this spatially and significant unit has been demoted simply to a member of a newly proposed formation called the Orara Formation. The Orara Formation itself has two distinct formations the demoted Kangaroo Creek Sandstone Member and the new Bungawalbin Member. (See figure 2).

The Woodenbong beds don’t get a guernsey at all in this paper. I suspect that this is because it would better fit into either the Bungawalbin Member of the Kangaroo Creek Sandstone or the Piora Member of the Grafton formation. More work needs to be carried out to make it more certain.

Clearly we do not understand much about the Clarence-Moreton Basin. Even the shallowest geological components! Knowledge keeps improving the more people investigate. The paper provides further interest because identification of the stratigraphic units and geochemical data obtained provide an indication of the risk associated with groundwater resources and CSG production. So as usual, further blog posts are required.

References/bibliography:
*Doig, A. & Stanmore, P. (2012). The Clarence-Moreton Basin in New South Wales; geology, stratigraphy and coal seam gas characteristics. Paper presented at the Eastern Australian Basins Symposium IV, Brisbane.
*Wells, A.T. & O’Brien (1994). Geology and Petroleum Potential of the Clarence-Moreton Basin, New South Wales and Queensland, Australian Geological Survey Organisation, Bulletin 241.

The Game of Thrones - Geological Map

Time again to delve into the region of geological fantasy. I have previously noticed that Middle-Earth from the J.R.R. Tolkien’s Lord of the Rings has had its climate modelled. But I’ve never seen anybody actually recreate a fantasy world’s geology, until now. Miles Traer and Mike Osborne from Stanford University has done just that. He has created a geological map and recreated the geologic history of the lands from the series Game of Thrones.

I’ve only watched one episode of Game of Thrones myself. I found it a little to confronting and violent. Yet, the storyline was very good. I can see why people really like the series. Though I’m a little surprised that someone is obsessed enough to develop a geological history of the area.

Miles Traer’s blog on the geology of Westeros and Essos can be found here.

Mike Osborne’s account of the geology of the Game of Thrones lands can be found on the American Geophysical Union Blog here.

Clarence-Moreton Basin CSG Bioregional Assessment with some Philosophy

I was fortunate enough to be invited to a short presentation on hydrology and coal seam gas in the Clarence-Moreton basin last week. It was particularly good, in part, since lunch was provided and one of the presenters from the CSIRO ended up being someone I knew but had not seen for nearly a year. The topic of the presentation was an assessment that has recently commenced on the effects of coal seam gas (CSG) on water resources. Alas, it is something that the media has all but ignored. So a bit of information and a bit of philosophy in the blog post today!

This year a large investigation (a bioregional assessment) into all the possible effects of CSG on water commenced in earnest. It is a project funded by the Federal Government with many scientific project partners including the CSIRO. The project is based exclusively in the first case, on the compilation of scientific information. It is at arms-length from government and politics, so it is entirely technical. Therefore, this assessment is something which I personally find interesting and feel is of great value. The project scope has been set up by the Independent Expert Scientific Committee on Coal Seam Gas and Large Mining Development. The committee was established in 2012 and works under the authority of the Environmental Protection and Biodiversity Conservation Act 1999. A link to the CSIROs summary of its involvement can be found here.

The Clarence-Moreton basin bioregional assessment itself is one part of many bioregional assessments in numerous Australian coal basins. These assessments are themselves divided up into many different components including hydrogeology, ecology, ecotoxicology, environmental protection and many others. The presentation that I attended was specifically related to the hydrogeological modelling that is being developed. It briefly covered the different data sources and data limitations that were going to go into the modelling. It was good to see the thoughtfulness and consideration given to all the hydrogeological issues. Sometimes just figuring out what needs to go into a model is very hard in itself… but by far the hardest task is making sure the modelling reflects the real world. This is because of the varying amounts of "weighting" required to each of the input variables.

However, one of the things that saddens me is the lack of media time this assessment has been given. Many people are concerned that not enough is known about CSG activities in our region or in Australia or even more broadly, around the world. The media tends to focus on the conflicts that are occurring and not on the advances in technical knowledge that will lead to better decision making in the near future. The media does not seem to like reporting on things that we are learning but instead increases the confusion about matters that could lead to social conflict. Conflict, not cooperation seems to sell newspapers these days.

I was also a little saddened by some questions that were asked of the CSIRO presenters. One (Environmental Economics and Policy Academic!) asked whether it was ethical to undertake this assessment because it may lead to a CSG development being regarded as “safe”. To consider an increase in human knowledge of the world in which we live un-ethical is a big worry for me. Especially from a senior academic. In many ways it questions the very basic concepts of scientific endeavour. Having a scientific background, I feel we should not avoid learning something new because the facts that may arise could potentially contradict with a pre-determined world view. We are of-course moving from science to philosophy. I know my philosophical motives in life are to use knowledge to give the best outcomes for the environment and people that live in our region.

So, to end on this philosophical note: I recommend thinking about the knowledge that we have and how we use or ignore it. The media practice of looking only at conflict and dumbing down its stories on scientific and technical matters is well entrenched. I’m starting to genuinely believe that the media is making it harder to distinguish between facts and opinions purely in the media’s self-interest of creating a story to make money from. Recognising this is helpful to understanding where scientific information can guide us in the right decisions, as such I provide here a link to an ABC presentation on the media by an excellent modern day philosopher (one of my favourite non-science authors) Alain De Botton.

Where Does the Groundwater Flow?

There has been renewed interest in groundwater resources in the Northern Rivers of late. In part this is due to peoples concern about "unconventional" gas exploration and production in the area. Surprisingly, less known is the release of Rous Water's Future Water Strategy which includes groundwater as first on the list for new water sources. Rous Water is a major bulk drinking water supplier in the region. I've previously covered an area within the coastal sands groundwater source called the Woodburn Sands but this was a cursory look and I'd not covered where the groundwater actually goes.

Groundwaters do not exist as an underground lake in our region
Image courtesy of International Association of Hydrologists

Groundwater is often seen as a bit of an unknown, a black box, or some kind of underground lake (see the cartoon). It is quite difficult to observe and therefore people can get the wrong idea of what goes on underground.

One area that is not understood is that groundwater usually discharges somewhere. Sometimes groundwater discharge is obvious through springs. But where it intersects with permanent surface water it is much less obvious. The Evans Head area is a good example of where discharge from the Woodburn Sands aquifer and broader Coastal Sands aquifers is concealed.

Spring-fed creek on Chinaman's Beach.

While walking along Chinaman's Beach south of Evans Head during a recent long dry spell, I couldn't help notice the dark coloured water flowing over parts of the beach. This is one of those discharge areas I'm talking about (most people might be more used to seeing freshwater flowing over a beach from contaminated urban stormwater drains). The coastal sands above Chinaman's Beach holds groundwater and slowly discharges it at the beach. The dark colour of the water is from dissolved humic matter from coastal vegetation soaking into the sand. Tasting the water it was apparent there was no salt in it and understanding the groundwater area I knew it was clean. The springs I observed on Chinaman's Beach were obvious areas of groundwater discharge. The vegetation in the springs was lush and clearly reliant on the groundwater. This is formally known as as groundwater dependent ecosystems.

The lesser known discharge is not all through visible springs like those on Chinaman's Beach. Much of the discharge from the coastal sands aquifers is actually concealed by the sea. It might be a surprise to many in some areas just off the coast there are zones with freshwater. The amount of water that can be discharged underground into the sea can exceed the discharge from terrestrial springs (e.g. Santos et al. 2009). These are the undersea equivalent of the Chinaman's beach springs. This is interesting from a aquatic ecology point of view because it may mean that there are ecosystems in the ocean that are dependent on freshwater! That is, groundwater dependent ecosystems in the sea.

Groundwater is an interesting feature of our region. It is a source of drinking water, irrigation water and even industrial water. It is often important as some ecosystems are dependent on it. It is also surprising since ecosystems can be dependent on fresh groundwater even when out to sea.

Postscript: about a month after this blog post a story emerged in the local newspaper about sinkholes or zones of quicksand on Chinamans Beach. These quicksand 'pits' look just like typical groundwater discharge areas. The Northern Star article can be found here.


References/Bibliography:
*Santos, I.R, Burnett, W.C., Chanton, J., Dimova, N. & Patterson, R. (2009). Land or Ocean?: Assessing the driving forces of submarine  groundwater discharge at a coastal site in the Gulf of Mexico. Journal of Geophysical Research. vol114.