Cowrie siltstone is a formation within the Proterozoic Rocky Cape Group. It consists of black pyritic shale with interbedded siltstone. At Cowrie Point it exhibits fretwork and honey comb weathering with phyllite and slate sequences in tilted rocks.
Strike and dip refer to the orientation or attitude of a geologic feature. Strike is defined as the direction of the line formed by the intersection of a fault, bed or other planar feature and a horizontal plane. Dip is the angle at which a planar feature is inclined to the horizontal plane; it is measured in a vertical plane perpendicular to the strike of the feature. Specialised compasses and clinometers are used to measure these readings with great accuracy. However the device the average cacher holds in their hands is sufficient for our purposes today.
Strike and dip of the beds. 1-Strike, 2-Dip direction, 3-Apparent dip 4-Angle of dip
At the listed co-ordinates you should be standing on a rocks exhibiting an obvious horizontal feature. They could be described as parallel train tracks. To log this earthcache you will need to answer the following questions using the email link at the top of this page.
Q1. Using your GPSr or a compass, determine the rough strike direction of these parallel lines.
Q2. Immediately on the seaward side you will see rocks that have been raised at an angle. Determine their rough dip direction.
Q3. Using whatever means are at your disposal estimate the rough average distance between the parallel lines.
Q4. Similarly, estimate the rough average height of the raised rocks. Note you should not need to move more than a step of two from the listed co-ordinates to do this. Ignore those in the distance.
Q5. Finally, looking immediately to the landward side from the listed co-ordinates, describe in your own words how the rocks differ from those on which you are standing.
You are welcome to log the cache before you receive a reply email from me, but if I do not receive the correct answers I will be obliged to delete your log. Please do not post your answers in your online log.