9:22 those conical seashells are identical to something ive come across that has me thinking tsunami as well. After seeing an OzGeographics video months back about the subject it had me checking out some undisturbed bush just over 1km from the beach. Theres an narrow drain only about a metre or 2 wide cut through a section of it that appears to be many many many years old. Anyways. Theres an entire sedimentary layer with those conical shells plus larger seashells. We've even found a couple of different types of coral in boulders that have been clearly been dug out when the drain was created... I really should try make a video of my own and contribute to all this..
I need to get these shells carbon dated as well. That will be very interesting. Do you have the latitude and longitude of your location? (find it on google maps and place a marker, is how i do it)
There was no sand blown inland during cyclone Alby because the winds were predominantly northerly and having very clear memories of it, this is the first time I've heard of a fence being blown from Swanbourne to Cottesloe.
Anstey beach has reduced surf as the golf course has stopped the carryover of sands from the easterly winds! Warnbro sounds beaches (as well as Dungah island) have been inundated with sand caused by the scouring of the tides diversion by the Garden island causeway
Hello. I live in Albany. You seem to miss us. There is Noogyar history of the Sea being far away. An event brought it closer. We have a lake here the shape of a footprint. Lake Seppings. Have a look?
What abut Mt Brown? I'm from Perth and whilst I think it's likely the WA coast has been hit by tsunamis, if you go back far enough I'm not entirely convinced. The thing is the old coastline was much further out.
The coastline has definitely advanced and retreated by many kilometres over the last millions of years as ice ages have come and gone. My latest research is indicating sea level change causes instabilities in the continental slope leading to tsunamis. Go back 10s of millions of years as the Indian Ocean formed and the coast would have seen countless earthquake generated tsunamis. Research is ongoing.
I'd like to send a photo of the cross section of the quarry at Bold Park which very clearly shows aeolian sand layering but only for the top 2 or 3 metres. Everything below that is undifferentiated and therefore laid down at the same time. Is there an email address to send that to? Alternatively go and see yourself. As you sit in the amphitheatre it's the right hand (South wall) that shows it very clearly.
I have not been inside the quarry amphitheatre itself as of yet, I have been meaning to at some point. I have been to other parts of Bold Park, but not at any rock outcrops. In the mean time yes I would love to see the images. Trying not to be spammed.... my name is Simon and my website is called PerthLight.
The conical shells you found at 9:04 are likely Cochlicella sp., possibly C. acuta. Most importantly they are a terrestrial snail and not from the marine environment.
Ah Ha. I think you are correct. Thank you. Back to the drawing board on this one. I still have some bivalve fragments collected from over 3km from the sea in Margaret River.
I have just added a disclaimer to the video description: Update: I have incorrectly identified some snail shells in this episode as being from a marine environment, but they are actually land snails: they are likely Cochlicella sp., possibly C. acuta.
I like where youre going with this. I have so many questions. Let me interview you one time via zoom. Im currently in Cairns and im obsessed with the tsunami topic.
Hey Jacob, yes I would be happy to speak to you on the subject. I have a lot more research completed than I can put in the videos. More than happy for you to put the video up on your channel too, I would likely record it and do the same.
Do you have a new time scale for this tsunami? Or are you suggesting this is the deposition of multiple tsunamis? I would like to see carbon dating of organic samples from various depths to find out how long they must have been resident in this inland soil, if it’s possible to collaborate with any local universities
The timescale for this main south west Western Australia tsunami event comes from research in the 2000s on some granite boulders. They have intact barnacles on them which were carbon dated to 5000 years ago. The barnacles could only have formed in the sea, there are very small tides in this region, and at no point in the recent geological past was the sea level higher in this region, no tectonic or isostatic uplift of the land out of the sea. The only natural force that could lift them out of the sea is a tsunami. That's how we get the date. I will be looking at these granite boulders in a future episode. I have multiple shell samples from various locations that I would like to get carbon dated, but it's a huge cost unless I can get some collaborations going. I will work on this once I have more data, and more episodes. Yes I can see several possible tsunami events as there are some locations with older chevron dunes and saline deposits farther inland from what look like fresher events. That's a future episode already planned.
9:22 those conical seashells are identical to something ive come across that has me thinking tsunami as well. After seeing an OzGeographics video months back about the subject it had me checking out some undisturbed bush just over 1km from the beach. Theres an narrow drain only about a metre or 2 wide cut through a section of it that appears to be many many many years old. Anyways. Theres an entire sedimentary layer with those conical shells plus larger seashells. We've even found a couple of different types of coral in boulders that have been clearly been dug out when the drain was created... I really should try make a video of my own and contribute to all this..
I need to get these shells carbon dated as well. That will be very interesting. Do you have the latitude and longitude of your location? (find it on google maps and place a marker, is how i do it)
There was no sand blown inland during cyclone Alby because the winds were predominantly northerly and having very clear memories of it, this is the first time I've heard of a fence being blown from Swanbourne to Cottesloe.
Then fence incident was relayed to me by a local who witnessed the event who described it as being rolled up like a ball of wool.
i was waiting patiently for this installment. Thanks very informative.
Glad it was helpful!
Anstey beach has reduced surf as the golf course has stopped the carryover of sands from the easterly winds!
Warnbro sounds beaches (as well as Dungah island) have been inundated with sand caused by the scouring of the tides diversion by the Garden island causeway
Hello. I live in Albany.
You seem to miss us.
There is Noogyar history of the Sea being far away. An event brought it closer.
We have a lake here the shape of a footprint. Lake Seppings.
Have a look?
I will be visiting Albany and surrounding areas during this research. Simply have not yet got round to visiting, but it is on the itinerary.
What abut Mt Brown? I'm from Perth and whilst I think it's likely the WA coast has been hit by tsunamis, if you go back far enough I'm not entirely convinced.
The thing is the old coastline was much further out.
The coastline has definitely advanced and retreated by many kilometres over the last millions of years as ice ages have come and gone. My latest research is indicating sea level change causes instabilities in the continental slope leading to tsunamis. Go back 10s of millions of years as the Indian Ocean formed and the coast would have seen countless earthquake generated tsunamis. Research is ongoing.
I'd like to send a photo of the cross section of the quarry at Bold Park which very clearly shows aeolian sand layering but only for the top 2 or 3 metres. Everything below that is undifferentiated and therefore laid down at the same time. Is there an email address to send that to?
Alternatively go and see yourself. As you sit in the amphitheatre it's the right hand (South wall) that shows it very clearly.
I have not been inside the quarry amphitheatre itself as of yet, I have been meaning to at some point. I have been to other parts of Bold Park, but not at any rock outcrops. In the mean time yes I would love to see the images. Trying not to be spammed.... my name is Simon and my website is called PerthLight.
The conical shells you found at 9:04 are likely Cochlicella sp., possibly C. acuta. Most importantly they are a terrestrial snail and not from the marine environment.
Ah Ha. I think you are correct. Thank you. Back to the drawing board on this one. I still have some bivalve fragments collected from over 3km from the sea in Margaret River.
I have just added a disclaimer to the video description: Update: I have incorrectly identified some snail shells in this episode as being from a marine environment, but they are actually land snails: they are likely Cochlicella sp., possibly C. acuta.
We have squeaky sand when you walk on it.
That's the quartz grains. I will be taking a closer look at what the beaches are made up of in a couple of episodes.
Keep up the good work👍
thank you
I like where youre going with this. I have so many questions. Let me interview you one time via zoom. Im currently in Cairns and im obsessed with the tsunami topic.
Hey Jacob, yes I would be happy to speak to you on the subject. I have a lot more research completed than I can put in the videos. More than happy for you to put the video up on your channel too, I would likely record it and do the same.
Do you have a new time scale for this tsunami? Or are you suggesting this is the deposition of multiple tsunamis? I would like to see carbon dating of organic samples from various depths to find out how long they must have been resident in this inland soil, if it’s possible to collaborate with any local universities
The timescale for this main south west Western Australia tsunami event comes from research in the 2000s on some granite boulders. They have intact barnacles on them which were carbon dated to 5000 years ago. The barnacles could only have formed in the sea, there are very small tides in this region, and at no point in the recent geological past was the sea level higher in this region, no tectonic or isostatic uplift of the land out of the sea. The only natural force that could lift them out of the sea is a tsunami. That's how we get the date. I will be looking at these granite boulders in a future episode. I have multiple shell samples from various locations that I would like to get carbon dated, but it's a huge cost unless I can get some collaborations going. I will work on this once I have more data, and more episodes. Yes I can see several possible tsunami events as there are some locations with older chevron dunes and saline deposits farther inland from what look like fresher events. That's a future episode already planned.
Great stuff thumbs up👍