Topic: Stacks - Follow-ups
PLEASE NOTE: Dates recorded AFTER 18.9.2010 will be FOLLOW UPS ONLY as the Tongaporutu Project is now completed.
The follow ups will mostly be limited to the Three Sisters beach and the Four Brothers beach. However, should anything major occur at any of the other locations, then they will also be recorded.
FOLLOW UPS TO THE MAIN TONGAPORUTU PROJECT
THE THREE SISTERS BEACH
THE SISTERS. The New Sister was still attached to the mainland cliff. However, it is only a matter of time before the increasingly tired looking main fracture lines finally succumb to wave smashing. There was also secondary cracking and carving evident along the base of the parent cliff. This carving extended beyond the main fracture lines and continued southward along the base of the New Sister for a short distance. This was probably due to backwash.
PHO2012-0512 is just a standard view of the Four Sisters, but by using the panoramic camera, I was able to have them all lined up in this single image. Of course it would have been much better with a brilliant sunset, but unfortunately that didn’t coincide with this exceptionally low tide. Ditto with PHO2012-0513 taken of the southern side of Elephant Rock.
All of the rock stacks appeared little changed from my last visit. The weather had been calm and fine for some time so I wasn’t expecting to see any dramatic changes. I was up at Tonga with Josefin Carlsson and Anders Fridfeldt from the University of Stockholm, Sweden. They were particularly interested in the rock structures and strata and the erosion that goes on up at Tonga.
18.5.2011 PHO2012-0523, 0619-0620
THE SISTERS. The umbilical cord attaching the New Sister to her parent cliff is still firmly in place. However, she is undergoing preferential carving at the base on the seaward side close to where she joins up with the cliff. (Northern end). This wave action has produced a small, blind ‘cavelet’ that is being carved in a north to south direction. The entrance is thus on the northern end. The cavelet is about 6 to 8 feet in length. I didn’t photograph this. I did photograph the Sisters from near Mammoth Rock.
ELEPHANT ROCK. This appears relatively unchanged, although it is looking a bit tired around the edges. I photographed this at an angle with Mt Egmont in the background. PHO2012-0620 was talem from the southern side looking north. The Middle and Inner Sisters are visible in the background.
3.7.2011 PHO2012-0531, 0632-0634
MAMMOTH ROCK. These two images show Mammoth Rock from two different viewpoints. PHO2012-0531 was taken from atop the southern end of the disintegrating dune. It’s hard for me to believe now that up until July 2008 this dune was joined to Mammoth Rock. This shows just how far the dune has retreated since then. PHO2012-0634 was taken from the Pilot Point dune which is also in retreat, but to a lesser extent.
THE SISTERS. The New Sister remains attached to the parent cliff. It will take a large cliff chunk collapse to finally free her, so this could be years away as most of the cliff collapse action taking place is at the northern end of the cliff section. The New Sister is located at the southern end which is more solid.
The other Sisters are unchanged. I hadn’t planned on taking yet another ‘postcard’ shot of them with White Cliffs and a sparkling Mt Egmont, but they were nicely reflected in a shallow pool on the beach, so, I couldn’t resist.
ELEPHANT ROCK. This appeared to be mostly unchanged. However, it does appear to be losing loose material on the southern side of the main trunk.
14.8.2011 PHO2012-0555, 0557, 0568, 0571
MAMMOTH ROCK. PHO2012-0557 is virtually a carbon copy of PHO2012-0531 taken last month, but there are differences in these two ‘timeline’ images.
THE SISTERS. Though the Sisters are quite small in the photo (0571), I have included them here because of the 5,000 old petrified totara log in the foreground. This gives some indication of the past sea level which was obviously much lower than it is currently. The land was also more to seaward as evidenced by the Sisters rock stacks.
The New Sister appears to be relatively unchanged. She is still firmly attached to her parent cliff. I believe she could remain that way for perhaps five or more years. The Inner and Middle Sisters appeared to be losing some material.
THE FOUR BROTHERS BEACH
While photographing from above the Twin Arches cave, I obtained a couple of rare viewpoints of firstly, the three remaining BROTHERS, looking north and PINOCCHIO, looking south.
Another unusual viewpoint of PINOCCHIO. This is looking through recently formed arch on the Fractal Rock.