Christmas Bells

Christmas Bells
Christmas Bells - Blandfordia nobilis

Wednesday, August 12, 2009

Rocks and rockpools at Bermagui

Here are some more photos from my visit to Bermagui, two weeks ago.

Firstly, here is a view of Mt Dromedary ("Gulaga" - to the local Aboriginal people) as seen from the boat harbour at Bermagui.
Mt Dromedary is a huge granite outcrop, and so it is the remains of huge igneous forces. Although its top is now about 1000 metres, it is estimated that it once stood 3 Km high. The formation of Mt Dromedary has left geological "reminders" along the coast from here to Narooma, some 60 Kms to the north. There are historic gold mines in the Tilba area, and even in a large vein of Quartz rock, close to Bermagui, near Camel Rock (the Montreal Goldfields".

From the boat harbour at Bermagui, one can climb down the point above the mouth of the estuary to the rock shelf below, just above the ocean. Around this point, the rocks are mostly soft mud-stone rocks, but there are some veins of quartz. You may recall that last week I showed some of the heavily metamorphosed rocks from the beach, near Camel Rock. Presumably this reflects the huge eruptions associated with the formation of Mt. Dromedary.

This patch of mud-stone rock has been lifted up. The vertical veins are left over from patterns of sedimentation, when the rock was laid down, in a horizontal position.Because it is relatively soft rock, it is eroding. It has left an intriguing small hole through which one can look to the sky.
or one can look back through the rocks below the cliff.
In the same area, I found this interesting large, smooth lozenge-shaped rock. It is sedimentary in origin, but has been subjected to pressure, with a thin vein of igneous rock injected through it, under intense heat and pressure.
By contrast, here is an interesting lozenge-shaped rock, with delightful pink stripes and soft tonings. It is clearly formed in a very different manner from the soft, smooth rock above.This was from the beach near Camel Rock.
Here are some shots from various rock pools.
A green Sea Anemone.
Some red Sea Anemones in different stages of "opening"
of their flexible tentacles.
These Sea Anemones are on a vertical side of a small rock pool.

UPDATE: I am endebted to Tsun-Thai Chai for identifying the red Sea Anemone as a "Waratah Sea Anemone" and the beaded algae as "Neptune's Necklace" (Hormosira banksii). By sheer coincidence, the first image I found of that Beaded Algae species is illustrated here, by another colleague of mine, James, of "Dermal Denticles". Small world!

Here is a dark Sea Urchin with its hard spines.
There is an interesting article on how to treat an injury
incurred by falling onto a Sea Urchin's spines.
Best to avoid, I think.
In the world of rock pools, this is what passes for "lunch".
A school of tiny fish swimming in a rock pool.
One hopes that they escape at the next high tide.

9 comments:

Tsun-Thai Chai said...

It sure took me a while but I think I found the name of the brown algae in the waratah anemone photo. It should be Neptune's necklace (Hormosira banksii).

Cheers,
Chai

Denis Wilson said...

Hi Chai
Many thanks for those IDs. Great to have you back "on the team".
Cheers
Denis
PS I happen to know James of "Dermal Denticles" whose album I found tonight, via Google Image Search for the "Neptune Necklace". James started out with a Flickr Album back in 2004, that I know of. He was a student then, and is now a fully fledged Marine Biologist.
See link from my "update" in the text above.
Cheers
Denis

James said...

Hi Denis,
Nice to hear from you. Glad that my neptunes necklace photo helped you with your id.
Hope you are doing well!
Regards,
James

Tsun-Thai Chai said...

Hi Denis,

No worries, mate : ) I just happen to know it because these anemones are very common where I go snorkeling. In fact, It may well be 50% of the anemone species I know : ) And I think I have also seen those brown algae before only that I couldn't be bothered to look up their name before this.

I checked out Dermal Denticle's photos - boy they are so beautiful.

Chai

Denis Wilson said...

Hi James and Chai
I love it when Blogging helps close the loop occasionally, as in this case.
Chai has just finished his PhD, and is looking to get into marine biology as a career. meanwhile he has been blogging from Perth's beaches for over a year.
James started in Sydney, but now appears to be on the NSW north coast.
Common interest, though.
James and I met through social contacts a few years ago. I normally stick to dry land, for my blogging. The best I do with rock pools is try to shot into the water - hence the blurred images. Anything more challenging than that would have me sea-sick. I went snorkelling with my brother several months ago, but needed to be rescued (well, gently assisted back to the beach) after a while. Water is not my element of choice. But I admire the images you guys take.
.
Cheers
Denis

Beth said...

Hi Denis
Do you think that Chai may know the distribution of the Waratah Anemone as they are so lovely, I look forward to seeing them. Are they around Wollongong??
Thanks Beth

Denis Wilson said...

Hopefully Chai will read your question, and post a reply comment.

If not, I will email him for you and reply here.

If you don't find them, you will find something else wonderful. Rock Pools are great.

Cheers
Denis

Tsun-Thai Chai said...

Hi Beth & Denis,

The waratah anemone is common throughout the southern Australian shores.

See distribution information HERE.

Cheers,
Chai

Denis Wilson said...

Many Thanks, Chai
.
Thanks for that link. Its an excellent site, which I had not seen before. I have saved it in my Bookmarks.
.
Hopefully Beth will get notified (if she ticked the box saying send reply to ....
.
Cheers
Denis