Hickeys Falls are located 42km southwest of Coonabarabran on the Oxley Highway.
The Warrumbungle Range is a 130km spur of the Great Dividing Range. Its many interesting formations are remnants of colossal volcanic forces that formed this spectacular and ancient landscape 18-15 million years ago. The formations and underlying bedrock are composed of basalt and trachyte.
Basalt is a common extrusive igneous (volcanic) rock formed from the rapid cooling of basaltic lava. Trachyte is a fast-drying lava which plugs volcanic craters and which remains after the softer surrounding cones have eroded.
Depending on the type of rock, and its susceptibility to forces such as erosion and weathering, bedrock will often determine the path of moving water such as rivers and streams. In this area the hard basalt and trachyte proved resistant to erosive forces over millions of years. However, the abrasive and erosive actions of water have eventually worn away the softer casing of solidified lava and ash and carved out a river’s course. This is the Castlereagh River and it flows down from Warrumbungle National Park.
The river’s 550 kilometre journey is occasionally broken by sandbanks that build up on the riverbed and contribute to its sluggish passage. The surrounding area is well known for its invaluable resource of extensive quantities of artesian water. It has never been short of water even in the driest of conditions. This is a result of the erosion-resistant properties of the deeper ancient volcanic flows and their ability to contain the water.
Hickeys Falls is a feature of the Castlereagh River and is just off a roadside rest area known as Devil’s Hole. It is a curtain ledge waterfall in which the bedrock stands at a height larger than the width of the falling water stream. The water descends over a vertical cliff, maintaining partial contact with the bedrock all the way to its base. The falls are at an altitude of 653.96 metres above sea level and plunge over its walls to a plunge pool below.
Hickeys Falls is easily accessible. It is a great example of erosive and weathering processes and displays a variety of resultant geological features.
You may log this Earthcache straight away but then please email your answers to the questions to the CO. We will contact you ONLY if your answers need extra work. Logs with no answers sent will be deleted.
The answers can be found by observing the landscape and a bit of research. Please do not post your answers in your log.
Take the short walking track to Hickeys Falls.
Q1. Estimate the height of the waterfall.
Q2. What is bedrock?
Q3. Standing at/near S31 25.742 E149.04.035 look at the rock wall to your right. Are the crevices in the wall horizontal or vertical?
Q4. Describe another weathered feature in the rock wall?
Q5. What large feature is at S31 25.755 E149 04.031? How do you think it got to be there?
Q6. Stand at S31 25.773 E149 04.016 and face the rock wall across the river. How do these rocks differ from those in the first rock wall?
It would be nice to see a photo of you enjoying this Earthcache. Please post one if you wish but no spoilers please.
A free camping area is provided with a wood barbecue and a picnic table but no toilets. It is preferable to bring your own firewood. There is room for large vans. Remember to take only photos and leave no trace of your visit. We hope you enjoy your visit to these interesting geological features.