Please be Croc safe. This cache may be more difficult at high tide, we appreciate the remote location of this cache means timing your visit with the correct tide maybe difficult, we are confident enough rocks will be visible at high tide for you to adequately answer the questions without standing right on the posted coordinates.
Welcome to Somerset, an incredibly historically rich part of Cape York. Regrettably we don’t have coordinates for the historical points but we are confident you will find them just as we did by doing a little exploring. Aside from the beautiful rocks we have brought you to see Geo mum was fascinated by the Pearl divers graves; it must have been an extremely remote part of the country back when those men died.
The most notable inhabitants of this area are Frank (son of John Jardine) and Sana Jardine who are buried in the nearby graves.
From Wikipedia: Francis Lascelles (Frank) Jardine (28 August 1841 – 1919) was an Australian pioneer associated with the exploration and settlement of Far North Queensland.
In 1864 Jardine, with his younger brother Alexander William Jardine, travelled 1200 miles from Rockhampton to Somerset on the Cape York Peninsula, at the time his father John's cattle station. They started with 42 horses and 250 head of cattle. The trip took 10 months during which time the party was constantly opposed by the area's inhabitants as they forced their way through scrub and swamps and crossed at least six large rivers, including the Jardine River which was subsequently named after him. They reached Somerset on 2 March 1865 with 12 horses and 50 cattle. Jardine's men survived, in poor health; they left a trail of dead Aborigines, dead horses and cattle and all their equipment Jardine claimed to have personally killed 47 people, with a total death toll for the trip of over 200. Both brothers were elected Fellows of the Royal Geographical Society and received the Murchison Award. In 1866 Frank settled on a station near Somerset and was appointed police magistrate in 1868. He died in 1919 of leprosy and is buried at Somerset with his Samoan Princess bride Sana Solia.
Sana was a little like Geo mum, she LOVES ROCKS! While exploring the area check out the old Mango tree behind the rusty cannons, S 10° 44.636 E 142° 35.595 you can still see the remnants of one of Sana’s rock gardens!
It is customary with an Earth Cache to present an Earth Science lesson to the ‘finders’, whilst putting this lesson together we learnt a lot ourselves too.
At/near the posted coordinates you will be surrounded by rocks, most of the rocks you will find are Sandstone, we were amazed at the dark colour and the notable differences in colour texture and density between the rock fragments that seem to have come from the same larger rock base. Placing an Earth Cache was on our minds when we found the area but we were lacking knowledge, not even Google could help us. We enlisted the help of a FNQ Geologist John Nethery.
From John: All of these are from the Albany Pass Beds of the Late Jurassic age (145million years old) Carpentarian Basin, which in turn is part of the Great Artesian Basin, which occupies most of western Queensland and extends as far south as SA and NSW. The Albany Pass Beds form low cliffs on the headlands locally. Coarse pebbly sandstone to conglomerate can be seen. There has been substantial leaching out of clay rich material by the effects of salt water saturation, wind and wave action to give a honeycombed effect. The photo ‘B’ obviously has a fault penetrating through it which from the appearance seems to have had iron oxide rich fluids permeating. Specular haematite (hematite Fe2O3) has deposited from solution on the fault plane as the faulting was taking place – The shiny black stuff. You can see that the specular haematite has an elongate streaky texture which represents crystallisation as the fault was moving. The elongate pattern showing the fault movement is called “slickensides” - a German term.
Some of the photo's John referred too.
In geology, a slickenside is a smoothly polished surface caused by frictional movement between rocks along the two sides of a fault. This surface is normally striated in the direction of movement. The plane may be coated by mineral fibres that grew during the fault movement, known as slickenfibres, which also show the direction of displacement. Due to irregularities in the fault plane exposed slickenfibres typically have a stepped appearance that can be used to determine the sense of movement across the fault. The surface feels smoother when the hand is moved in the same direction that the eroded side of the fault moved (see diagram for explanation), as the surface steps down in that direction, like the scales on a fish when stroked from the head.
In pedology, the study of soils in their natural environments, a slickenside is a surface of the cracks produced in soils containing a high proportion of swelling clays. Slickensides are a type of cutan. In the Australian Soil Classification, slickensides, along with lenticular structural aggregates, are an indicator of a vertoso.
We hope those explanations have given you a little insight to the Sandstone of the area and enable you to answer the questions required to log this Earth Cache.
To log this Earth Cache we require you to wander around and look at the area and what is available to you visually, consider the information given and perhaps if you need to do some research of your own, then message us with the following answers to the best of your ability;
1. From John’s description are you able to find a piece of rock with slickenside visible? Describe its size and texture?
2. If you look West up into the bush you will see a tall Sandstone wall, there is a clear difference between the rocks on the beach and this wall, what is it?
3. Looking at the photo above labelled A, B, C, D can you find an example of one or more of those pieces pictured? Considering John's explanation of the rocks in the area what do you think you piece is an example of, if you don't know the technical name using A, B, C, D as a reference in your answer is fine.
4. At the reference point you will be standing near some cannons and several large Mango tree’s here you should be able to find remnants of Sana’s rock gardens. Are the rocks used in her garden different to those down on the beach? Why do you think this is the case?
5. A photo of your team, GPS or the view with your log please. (Optional)
You are welcome to log your find straight away to keep your TB's and Stats in order but please message us with your answers within 24 hours. Cachers who do not fulfil the Earth Cache requirement will have their logs deleted.
We haven’t included it in todays earth science lesson as we have not visited the cave ourselves but we would like to point out some Aboriginal rock art in a Sandstone cave not too far away. If you head north following the headland around you will come to a large cave. Please be mindful of the environment and don’t take any unnecessary risks. If you do make it to the cave please post some photos we would love to see it.
Source: Wikipedia, www.cape-york-australia.com, John Nethery.