Topic: Strata - Gibbs' Fishing Point
GIBBS FISHING POINT
Access to Gibbs’ Fishing Ledge after which Gibbs’ Fishing Point is named, is an arsehole. A narrow ledge has been formed part way down the cliff which fishermen fish from. The ledge is approximately eight to ten feet across, then the cliff drops sheer to the sea. During storm conditions, big waves frequently overtop this ledge as evidenced by debris deposited there from time to time. There are two ‘tracks’ that one uses to reach the ledge, neither of which are really safe, being either crumbly during dry weather or slipperly during wet weather.
Just above the Gibbs’ Fishing Ledge and below the cliff-top proper there is a strata that contains the remains of fossilized trees. This is only visible from the fishing ledge, it is not noticeable from above.
Gibbs’ Fishing Point is particularly notable for its wall-like cliffs. I call the cliff face that is located at the southern end of the Four Brothers beach the Wall. Cathedral Cave is on its landward side. The cliff face on the western side where Gull Rock is I call the Mega-Wall.
1 December 2003
This was the first time I was able to access the fishing ledge proper. I very gingerly made my way down the crumbly track to join some fishermen. My reason for coming down here was so that I could obtain a clean photo of Gull Rock minus the intervening cliff.
Down on the ledge, I discovered an old fishing knife stuck into the cliff. More than that though, I was amazed at the sight of old tree trunks embedded in a narrow strata band. They were quite brittle to the touch and broke off fairly easily. I assumed that due to their height above sea level, that they’d been destroyed in a past volcanic eruption. Mt Taranaki was the obvious suspect.
These fossil tree remains were different to the ones located at Te Kawau and Twin Creeks. Those trees more closely resembled stone trees, in that they were solid and not prone to breakage like the ones here.
At this fishing ledge, due to wave smashing action, the tree corpses are being preferentially eroded out. I don’t believe that water, either salt or fresh, is the cause of the trees’ fragility here because the trees at Te Kawau Pa and Twin Creeks are subjected to more frequent water innundation.
The conclusion drawn is that the fossilized trees at Te Kawau Pa, Twin Creeks and to a lesser extent on the Three Brothers Beach were destroyed by a rising sea level. The trees contained in the Gibbs’ Fishing Point strata, being around 80 feet above sea level were most probably destroyed by a volcanic eruption. The reason for their ‘carbonisation’ and brittleness is perhaps due to volcanic acidification processes as opposed to salt/fresh water action.
29 February 2004
This shows the Wall at the end of the day when Super-Storm Three was winding down. This storm was significant, not because of big seas, but because of the huge amount of rain that it delivered. The colour of the water is due to massive soil bleeds that occurred on Beach One. The predominantly soil cliffs of Beach One are particularly vulnerable to massive rain events such as this. (See Section Four on Cliffs and Section Two on Weather).
19 September 2005
This alpha storm was the most potent storm to strike the Taranaki coastline since the alpha storm of 29.9.2003. This latest storm also coincided with the highest tide of the year at 3.9 metres. The photo shows the entrance to Cathedral Cave with a massive wave slamming into the Wall on the seaward side of the cave. The shock-waves generated by such powerful waves created Cathedral Cave and are a continuing force in its evolution. Conversely, the wash entering the cave, though a contributing factor in the cave’s evolution, has insufficient energy to create such a cave in the first place.
20 April 2008
I wanted to return to the ledge to re-photograph the petrified tree trunks that I had first spotted on 1.12.03. I used the track the fishermen who were currently there had used, not the one I had originally used. Their track hugged the cliff close to the edge. It was damp but not wet. Too wet and you could slip off. Too dry and you could slip off. This was the one place at Tongaporutu that I felt extremely uncomfortable and scared of being at. Perhaps because it is a sheer drop from a narrow ledge to the sea below. Also, here more than most other places, the sea slams into the cliff face with such ferocity. Even on calm days like today, the rollers were slinking up the cliff, trying to snatch the unwary. Get caught in one of those and you’d be slammed into the cliff and end up as mince meat.
On the ledge, I could see close up, the huge cracks appearing in Gull Rock. I could also hear with unnerving clarity, the waves toying with the cliffs. And a chunk of the ledge I was standing on had very recently been chomped out by a rapacious wave.
I then got down to business to affirm my first impressions. The logs were in two colours mainly, being dark brown/black and a normal brown. All looked as if they had been seered by heat and the logs were all flaky and charred looking. They were very brittle to the touch and crumbled under pressure. The grey/black tree stumps were all in a specific strata of rock that was roughly about eight feet wide. Below this, the cliff was of the normal yellowish sandstone mix. And above it the cliff was a yellowish sandstone mix. I assumed that the smashed trees had been decimated by some past calamity due to their height above the sea. Perhaps the last major eruption of Mt Egmont. Or perhaps even earlier. Lake Taupo? No, it was more likely to have been Mt Egmont.
I took 3 photos to illustrate different points of interest. One image showed two dislodged log remnants sitting on the ledge. They are being systematically carved out by huge waves that surge up and over the cliff at this point during storms. One photo shows a close up of a log and another shows the sharp dividing line between the cliff proper and the tree bearing strata.
31 March 2010 PHO2011-1796
Due to a magical combination of a 0.1m low tide, calm conditions and a very high beach state, I was able to access the seaward side of the Gibbs’ Fishing Point for the first and only time to date (February 2011).
This is the Mega-Wall. Like its smaller cousin, the Wall, it has a remarkably flat surface with none of the large, three-dimensional fracturing that is evident on most of the other cliff faces. The more two-dimensional the surface area the less susceptible it is to wave carving. As with a dolphin’s skin, water flows more smoothly over an unobstructed surface – the smoother the surface, the lower the resistance or surface tension.