Overview

Sharon Gorge Nature Park is a rest stop and nature park between Bundaberg and Gin Gin, with a walk from the rest area to the Burnett River along a creek. The term Gorge seems more of a confidence-building name for the creek gully because it doesn’t look like you would expect a gorge to be there.

The 900M walking track leads from the rest area along the creek and is fairly well maintained and easy to follow, with a few log steps and boardwalk at the low areas and across other water courses joining the creek. The trail ends at a platform above the 200m wide Burnett River to the banks of the farmland on the other side. The trail was opened in 1988 as a Bicentennial commemoration, indicated with a plaque. An information board provides details about the subtropical rainforest in the gorge and how the gorge was formed.

Nearby are the Mystery Craters. A visit could be of interest to contrast the rocks in the area but it is not a part of this EarthCache due to an entrance fee and restricted opening hours. An interesting feature of the Mystery Craters is the red ochre evenly distributed throughout the sandstone, as if the ochre was mixed through it. There are a number of theories on the formation of the mystery craters by scientists from across the world, but none have been able to be proven. Some facts have been proven, such as the craters like these are normally volcanic in nature but these craters are not volcanic, further adding to the mystery. Other theories include hot spring activity, it was once part of the sea, and the one that isn’t proven or disproven, it is a meteorite that didn’t disintegrate and landed in seawater or wet marshy area and was about to disintegrate giving the distributed ochre and sandstone features but held together. Theories it has something to do with aliens or dinosaurs have also been raised, a large dinosaur model sits near the viewing platform to support the stories.

The farmer who owned the property when the craters were discovered had the area cleared for planting more crops. The stories all tell of the farmer clearing the land himself. However, Edward Stanley Brian, told of the job he was hired to do. He was to clear farmland and when the grader hit rock the craters were found.

Geology

This creek gorge is a steep-sided, narrow valley with a river or stream running along the bottom. Gorges are formed by the interplay of several geological processes, including erosion or tectonic processes such as vertical uplift and cavern collapse. At WP2 there is a great example of erosion by the resident body of water. This is usually the primary contributor to gorge formation and is the evident source here. The continuous flow of water and abrasion by debris in the water eventually cuts a deep trench through the landscape that exposes many layers of rock. Rock and soil being moved by the water also act as the abrasive agents while being moved.  

A range of information sites tell you that six periods of volcanic activity have been recognized during the Cainozoic Era around the Bundaberg-Gin Gin-Pialba area. Cenozoic Era means "new life", it follows the Mesozoic Era and extends from 66 million years ago to the present day. Volcanic activity usually results in magma reaching the surface during an eruption. The rocks that form are called lavas or volcanic rocks and include basalt, andesites, dacites, rhyolite, pumice and obsidian.

You would expect to see these on our creek or gorge walk but at the start the first thing you see is examples of conglomerate rock. This forms where sediments of rounded clasts at least 2mm in diameter accumulate and are cemented together with mud or sand under pressure. At WP3 you get to see they are up to 60mm in diameter and it takes a strong water current to transport and produce a rounded shape on particles this large. So the environment of deposition might be along a swiftly flowing stream or a beach with strong waves. Such an environment is different to the many examples of volcanic activity the area is observed to have.

The flowing water over hundreds or thousands of years has found a weakness in the surface of the earth, possibly a depression and created a landform with a deep ravine which has steep walls. This offers shade, protection from the drying effects of wind and prevents hot fires. At WP4 the flow rate slows because the vertical fall within the gorge is reduced and walls opens out allowing subtropical rainforest vegetation to grow which in turn shades the forest floor and covering it with leaf litter. Here we see the deposits from erosion trapped and turned into a moist and fertile soil now rich in organic matter to support vegetation growth. Even in dry seasons, the soil retains moisture.

With the flow rate slowed, so is the amount of erosion and the water is transported to the Burnett River at WP5.

Time to take a walk and at each of the following WP’s answer the requested question. You can log a find immediately but must convey the answers to the CO via message within a week or two. If you fail to provide answers, you risk having your find log deleted.

WP2. S 24 53.051 E 152 14.553

Q1. Describe what has happened to the opposite bank?

WP3. S 24 53.078 E 152 14.553

Q2. What type of rock is most obvious here?

WP4. S 24 53.119 E 152 14.590

Q3. What is supporting the vegetation at this location?

WP 5. S 24 53.264 E 152 14.761

Q4. Please post a photo of yourself or a personal object, at the viewing platform when you log your find.