Topic: Strata - Twin Creeks

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Twin Creeks is situated immediately south of Beach Two.  Its southern impassable bluff leads around to White Cliffs.  Twin Creeks consists of high cliffs composed of embedded mudstones and sandstones.  The top layer consists of yellow/brown material that is derived from sand and volcanic ash.  Two creeks drain into the main beach area from opposite directions.  That is, from the north and the south.  At the northern end the land is slumping down to the beach.  Where the northern creek exits onto the beach there is a substantial, permanent debris field that primarily consists of flotsam logs and stones.

In the middle of the Twin Creeks area, the main beach curves landward to form a loose horseshoe type cove.  This cove is bounded at its northern and southern end by two creeks – hence the name, Twin Creeks.  The land between these two creeks is quite low lying and suffers from significant erosion.  The northern section of Twin Creeks consists of high cliffs, as does the southern section of Twin Creeks.  Both ends are bounded by high, impassable bluffs.

Another unique feature of Twin Creeks are the remains of fossilized tree trunks located in the beach and on occasion, being disgorged from land on the seaward side of the northern creek.  This particular section of land is slumping down towards the beach and is a highly active erosion hotspot.

2003

9 December 2003  

PHO2008-472

Upon arrival at Twin Creeks, the first thing I noticed was a number of stark tree trunks that thrust up sharply from the beach.  They were a very dark brown colour and obviously different from the bleached driftwood that had accumulated where the northern and southern creeks entered the beach.

The other main difference was that the fossilized trees were well and truly anchored in the sand whereas the other logs and driftwood were all topside.

 

2004

8 February 2004  

PHO2008-659, 661  (Examples only)

CLIFF SEQUENCING.

29 February 2004  

PHO2008-690, PHO2008-691

These two images taken during the third storm of the Super-Storm trilogy, show part of the beached log area and creek at the northern end of Twin Creeks.  (The landward side of the cliffs).

 

2005

6 November 2005  

PHO2008-1482, PHO2008-483

As the beach level appeared to be quite low, a lot of the ancient tree remains were exposed.  One tree remnant that was closest to the water had some nice green algae growing on it.  The fossilized trees were all dark brown/black in colour and very hard.

Photo PHO2008-1482 shows part of the northern creek and the permanent debris field leading onto the inner cove part of Twin Creeks.

2007

27 October 2007  

PHO2011-1077

The ‘rock’ in the foreground on the beach is actually the remains of a fossilized tree trunk.  Note the small mussels growing on it.

2008

9 March 2008  

PHO2011-1183

On the hillside up from the arch, another smallish slip now accompanied the massive slip that had been present for some months.  At the base of the large slip was the remains of a huge tree trunk.  This was, like the fossilized counterparts embedded in the beach, very dark in colour.  Possibly due to its size and weight, once a certain amount of surrounding fill had been sluiced away, then it was free to tumble to the bottom of the slip.  This too was perhaps part of an ancient forest.

The presence of an ancient tree that originated from high above sea level, plus trees embedded in the sand in the same location, could perhaps be indicators of twin events that occurred in the same time period.  Namely, sea level rise and volcanic activity.  Unfortunately, I didn’t physically check to see if it was stone-like in structure or brittle like the carbonised tree remains located at Gibbs’ Fishing Ledge.

Another possibility is that the trees located in the beach actually originated from land that had in the past been high above the sea.  Due to slumping and retreating northwards, the land has slowly disgorged its trees onto the beach.  They were perhaps destroyed in the same volcanic eruption as the trees located at Gibbs’ Fishing Ledge.  The few tree remains that are visible on the beach today are perhaps just the visible tips (having wicked to the surface) of a much larger tree graveyard that exists deeper down.

 

3 June 2008

I noticed that the lone fossilized tree trunk rising up on the southern side of the Middle Rock had even more of its trunk exposed.

12 October 2008  

PHO2011-1338, PHO2011-1339

PHO2011-1341, PHO2011-1342, PHO2011-1344

Between the arch and where the northern creek enters the beach, I noticed part of an ancient tree jutting up out of the sand.  This was the first time I had observed this particular tree remnant.  Also, the tree remnant on the southern seaward side of the Middle Rock was clearly visible.  As for the Middle Rock, in PHO2011-1341, the northern prominence has taken on the appearance of an Easter Island Moi.

More material had come down from the slumping land between the arch and the northern creek.

Where the northern creek enters the beach, the usual log-jam was present, but also lots of similar sized, roundish, mostly clean stones/rocks were piled up against the bed of logs.  I presumed they had been tossed up like giant grains of sand by a stroppy storm.  Just as sand beaches ebb and flow at the whim of the sea, so too these larger sized cousins.

15 December 2008  

PHO2011-1479

I accessed the beach where the northern creek empties onto the beach.  This spot which is just above the high tide mark in normal situations is usually jammed solid with logs.  Today was no exception.  On other occasions however, sometimes the logs are shifted further over and oversized ‘pebbles’ (rounded stones) are log-jammed here.  I have wondered whether these stones and their larger cousins, prominent on Beach Two (but not exclusive to Beach Two), are scaled up fractal versions of sand grains.  It would be interesting to see.  That is, if one could weigh and measure them and see if the differences do adhere to fractal scaling.

 

2009

20 April 2009  

PHO2011-1760

As I had to walk all the way down to Twin Creeks, I only took the panoramic camera.  Due to the high sand level, no fossilized trees were visible.  However, the right side of the photo shows where old logs are periodically disgorged from the slumping land that is constantly being eroded north.

On 9 March 08, I observed a massive, ancient tree trunk at the base of a large slip near the northern creek.  Later on, I believed that it had gone.  After looking closely at the panoramic image taken on the 20th, I am now not so sure.  The large fairly pointed ‘boulder’ close to the arch, could be the remains of that tree trunk first observed on 9 March 08.  I cannot however be sure.

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