Emma Gorge
PLEASE NOTE - El Questro NP closes in the off season. The website states it is closed from November to March due to it being very humid and wet.
Emma Gorge is a stunning place to visit but you do need to be of a reasonable fitness to get to the pool and waterfall at the end.
Emma Gorge is in the El Questro National Park and is approximately 80km from Kununurra. Access is via the Gibb River Road which is now a sealed road at the eastern end. The entry road to Emma Gorge itself is in good condition but is unsealed, about 2Km long and has a small water crossing just before the resort. If you are driving a 2WD it is recommended that you park just before the water crossing and walk the remaining 300m.
There is a National Park entry fee for El Questro NP. Fees can be paid at the resort or you can buy a parks pass online (and much cheaper)
https://shop.dbca.wa.gov.au/collections/park-passes
At Emma Gorge Resort you can find a bar/restaurant and accommodation which while staying is far from cheap is a very special experience. There are toilets and showers also. Not entirely sure if the showers are for use by day visitors but it didn’t stop us freshening up after the hike!
The walk up to the waterfall is about a 3.2km round trip. It is not easy walking though with lots of rock hopping and traverses across the small river. The path is however well marked with blue blobs to show the way. They recommend you have 2 hours to spare and that’s without a swim. Light was dropping when we last did it so we managed it in just over an hour with a swim but we went at a fair pace. We set off to the waterfall at 4pm in September and had the pool at the end all to ourselves.
The water from the falls is a bit cold but as you face the waterfall you might find people gathering in the water to the right hand side. Here is a small thermal spring which makes the water a much nicer temperature to wallow in.
Sandstone
Emma Gorge is made up of Cockburn sandstone and Quartz sandstone. Sandstone is a sedimentary rock and is made up of mainly quartz sand. These grains are cemented together with a matrix of silt or clay sized particles taking up the space between grains. Sandstone with a high quartz content can be used as a source of silica in the production of glass. Sandstone with less quartz content is still durable and is often used crushed in the construction industry. Sandstone can of course contain a variety of other minerals such as feldspar and the colour of the rock will vary with the mineral content. When sandstone contains more than 25% feldspar it is called arkose or arkosic sandstone.
Most commonly sandstone is light tan to orange due to the light coloured minerals it contains. Other examples though are Argillaceous sandstones which are often gray to blue. Redder sandstones have more iron content caused by iron oxide (rust) and some have a purple hue due to manganese.
Ripples in the Rocks
On the way to and from Emma Gorge you will get up close and personal with a lot of rocks. Many of them contain a ripple pattern.
These ripple patterns are formed by both water transport and wind transport of granular material, for example small bedforms in sedimentary rocks and larger bedforms such as sand dunes. Even those horrible lumps and bumps that develop on unsealed roads are formed in a similar fashion.
These ripples can form in either symmetrical (oscillatory currents) or asymmetrical patterns. When they form in one direction they are asymmetrical in nature – see diagram. One side of the rise is shallow with a pointed crest and the other side steeper. They are formed by such forces as rivers flowing downstream, longshore drfits and deep ocean currents. Oscillation or symmetrical ripples are caused when the mechanics occur in two directions such as wave action. These waves tend to have equal sides and a straight crest. In addition to erosion these ripples are subject to deposition of materials between the crests.
Questions
- Describe the sandstone that you see at Emma Gorge GZ. What colour is it and why do you think it is this colour?
- Along the path to GZ you should spot some rocks with ripple patterns. Describe the pattern you see and suggest if it is symmetrical or asymmetrical. How do you think they were formed?
- Feel free to add a non spoiler photo of yourself or your GPS device at Emma Gorge.
References (date accessed 24 Sept 2021)
Ripples in the rocks URL https://swaag.org/GEOLOGY/geology_ripples_in_the_rocks.php
The geology of sedimentary rocks URL http://www.intheplaygroundofgiants.com/geology-of-sedimentary-rocks/
Sandstone (Publ 3/4/17) URL https://mineralseducationcoalition.org/minerals-databse/sandstone/
Sandstone URL https://geology.com/rocks/sandstone.shtml