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Fossilised Seaweed Found On The Shotover

simon		Posted : Wednesday, 20 June 2012 7:38:59 PM(UTC)
Rank: Gold Ingot Groups: Registered Joined: 7/01/2011(UTC) Posts: 789 Location: Central Otago Thanks: 33 times Was thanked: 239 time(s) in 150 post(s)		hey, today i found something which i think is even rarer than gold in this locality. In fact i think it is fossilized seaweed. It is visible all over the rock on both side. From the look of one particular area of the rock the fossils have a fair depth to them. It would be really interesting to cut open. I may first show it to the museum. Not going out of my sight though. I'm presuming the rock is from the moonlight fault and the bob's cove beds in that. I've seen heap of fossilized oysters and the like but never anything like this. I will try and get a couple of pictures up later. This was found down at the shotover river by the jetboats off oxenbridge road. Don't know if i'd rush down there as i've never seen any other bits in all the years i've been down there.
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Lammerlaw		Posted : Wednesday, 20 June 2012 10:55:25 PM(UTC)
Rank: Gold Ingot Groups: Registered Joined: 24/05/2011(UTC) Posts: 1,721 Thanks: 72 times Was thanked: 579 time(s) in 396 post(s)		Looking forward to seeing the photos Simon Without seeing them I am wondering if you have been hoodwinked by Fossil Dendrites - these are pseudo fossils. They can look so much like genuine fossils of what looks like seaweed or moss that it is easy to mistake them for such. To me a give away is the fact that they are often on river worn rocks and the 'fossil' follows the contour of the rock whereas real fossils will be bedded along the layers of rock and not 'wrapped' around the rock. When they are wrapped around the rock it indicates that the image has formed after the rock has been river worn. http://www.panoramio.com/photo/34216377 http://museumvictoria.co...ncretions-and-dendrites/ And in the reference below photos the tenth, Eleventh and twelfth photos. http://www.geology.arkan...eology/pseudofossils.htm They are generally formed by an oxide of Manganese but they can also be formed by an actual seaweed growth on a rock which leaves a stain resembling a fossil though your one will not be of that form as they are found in rock pools at beaches or near the ocean and are recent in origin - IF your one is a dendrite then it will in all likelihood be a Manganese Oxide one. I have in the past found Manganese Ore in the Shotover River - I still have somewhere around a piece of Rhodonite from the Shotover and Rhodonite is a pink ore of Manganese. Well worth keeping however and as the Manganese Oxide and similar mineral formed ones are certainly not common in your stretch of the woods so a nice thing to have whether it be genuine fossil seaweed or a pseudo fossil, a dendrite.. Edited by user Wednesday, 20 June 2012 11:11:03 PM(UTC) \| Reason: Not specified

simon		Posted : Thursday, 21 June 2012 12:12:34 AM(UTC)
Rank: Gold Ingot Groups: Registered Joined: 7/01/2011(UTC) Posts: 789 Location: Central Otago Thanks: 33 times Was thanked: 239 time(s) in 150 post(s)		here's some photos of it. it's got a bit of the colour of green schist, and a bit just browny sand, which doesn't show too well in the pics. there is a small vien of quartz in it. majority is a conglomerate of grainy sand, mixed with a good sprinkling of quartz pebbles. i'm presuming this must be a boundary layer between the schists and the old sea bed? whether it is seaweed or not, i'm convinced there is something fossilized in this. on some of the surface you can see that the sand is actually a layer over the presumed fossils. there is one fossil that stands out. in the pic it looks like it has a hole / bit missing in part of it. in one part the flow of lines of 2 spots next to each other go in opposite directions so i don't think it is lines within the rock. the quartz vein is really close to the edge of the most prominent fossil. i presume the sands and fossils cemented at one point, and were later put under pressure and heat where i guess small cracks filled with quartz. File Attachment(s): _DSC0504.jpg _DSC0505.jpg _DSC0507.jpg _DSC0508.jpg _DSC0509.jpg _DSC0510.jpg _DSC0511.jpg
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Lammerlaw		Posted : Thursday, 21 June 2012 9:42:10 AM(UTC)
Rank: Gold Ingot Groups: Registered Joined: 24/05/2011(UTC) Posts: 1,721 Thanks: 72 times Was thanked: 579 time(s) in 396 post(s)		Extremely interesting Simon and the 'fossils' do appear to be embedded in the rock so that rather than a pseudo fossil or dendrite it might appear that you do indeed have a genuine fossil. I do not know if it is from the very furtherest reaches of Lake Manuherikia or not but if found further inland than the Nevis then more likely associated with the Bobs Cove formation though it doesnt appear to me to be so but I might be well and truly wrong. in any case the fossil is definitely of organic origin...in my opinion anyway! It looks very much like blades of grass with small pieces of twig or wood in it so a really nice find and one which I like and would very much like to see one day. You could well be correct in saying that it from the contact point between the sediments and the schist - interesting and fascinating...I like that sort of stuff and now I am just as keen for an answer as you will be so look forward to hearing a definitive statment made by a professional - Euan Fordyce at the University of Otago might be able to help you. Edited by user Thursday, 21 June 2012 9:44:24 AM(UTC) \| Reason: Not specified

simon		Posted : Thursday, 21 June 2012 11:16:34 AM(UTC)
Rank: Gold Ingot Groups: Registered Joined: 7/01/2011(UTC) Posts: 789 Location: Central Otago Thanks: 33 times Was thanked: 239 time(s) in 150 post(s)		damn it. you have got me more interested now in the rocks than than gold. yes, it isn't exactly seaweed but a mix of plant and stick. i know its hard to see in the pics but the leaf matter detail is pretty amazing, you can see each little fold of leaf. i have no idea how this made it down the gorges of the shotover this intact. clearly it has been tumbled but the fossils must be as hard as volcanic rock. definitely keen to show this to you. i am going to have to come over to dunedin in 2-4 weeks probably so will try and bring it with me and arrange to met up and show you. in the meantime i am hiding all my hammers as i had an urge to see what is inside it. i think it is loaded with material all through it. i've been reading several geology articles about the bob's cove bed's / moonlight fault etc. most likely i think this specimen has come down the moonlight which is just upstream. this would be the shortest route from the fault, but who knows. i'm tempted to look for other stuff out there now!
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Lammerlaw		Posted : Thursday, 21 June 2012 5:58:37 PM(UTC)
Rank: Gold Ingot Groups: Registered Joined: 24/05/2011(UTC) Posts: 1,721 Thanks: 72 times Was thanked: 579 time(s) in 396 post(s)		Yes you are probably right about the Moonlight as being the origin of your fossil or Stony or Skippers Creek You might like to have a perve through this reference here - a bit heavy going but such is life...at times. http://rsnz.natlib.govt....69/rsnz_69_01_000770.pdf Love to see it so looking forward to meeting and having a yarn, pass the time of day and having a look at the rock. Let me assure you that the temptation of busting it up always end in disappointment as I have foud many times but especially on two large Gold Quartz samples, one from Goodness knows where - where ever that might be and the other from the Morning Star in Fiordland. Me plus hammer equals disaster and in both cases what began as great specimens ended up in disappointing fragments - you leave it Simon - part of its attraction is the unknown! Edited by user Thursday, 21 June 2012 6:01:27 PM(UTC) \| Reason: Not specified

5AMP		Posted : Thursday, 21 June 2012 5:58:53 PM(UTC)
Rank: Gold Nugget Medals: Groups: Registered Joined: 3/11/2011(UTC) Posts: 57 Location: wellington Thanks: 105 times Was thanked: 16 time(s) in 11 post(s)		I agree with Lammerlaw, it does look like fossilised wood -sometimes quartz formations do throw up some deceptive specimens-I originally thought I had found a fossilised fern in this piece from the Martha mine at Waihi but it is just mineral staining. File Attachment(s): IMG_0469.JPG IMG_0466.JPG

Lammerlaw		Posted : Thursday, 21 June 2012 6:11:52 PM(UTC)
Rank: Gold Ingot Groups: Registered Joined: 24/05/2011(UTC) Posts: 1,721 Thanks: 72 times Was thanked: 579 time(s) in 396 post(s)		Originally Posted by: 5AMP I agree with Lammerlaw, it does look like fossilised wood -sometimes quartz formations do throw up some deceptive specimens-I originally thought I had found a fossilised fern in this piece from the Martha mine at Waihi but it is just mineral staining. That is what I originally thought that Simon's was as he had not by that stage put the photograph on - a dendrite or pseudo fossil - interesting enough in their own right and enough to fool all of us once - yes sir, been there and done that - caught out by the appearance - i guess that is how we learn..

5AMP		Posted : Thursday, 21 June 2012 6:18:49 PM(UTC)
Rank: Gold Nugget Medals: Groups: Registered Joined: 3/11/2011(UTC) Posts: 57 Location: wellington Thanks: 105 times Was thanked: 16 time(s) in 11 post(s)		Fossils and gold are not mutually exclusive-this one came from tailings near Lankey's Creek Reefton. It is devonian coral. Edited by user Friday, 22 June 2012 8:36:38 AM(UTC) \| Reason: grammar File Attachment(s): IMG_0470.JPG IMG_0471.JPG

simon		Posted : Thursday, 21 June 2012 10:38:43 PM(UTC)
Rank: Gold Ingot Groups: Registered Joined: 7/01/2011(UTC) Posts: 789 Location: Central Otago Thanks: 33 times Was thanked: 239 time(s) in 150 post(s)		5AMP, that's just as interesting. thanks for sharing. i might try and make an effort as re find some good examples of oyster shells in sand or mud stone. i'm sure they haven't gone too far as they are very large moeraki boulder sized. i've just read of mor eup in the mountain behind my house so might have a look up there if there's not too much snow and ice some day soon. your photo of the fern effect mineral staining i've seen somewhere on quartz boulders in tailings. just can't remember where. your first photos are similar to one lammerlaw showed me. i did wonder if it was some type of rock. one 'fossil' in particular has a small piece out of it showing how much depth there is. and the 'fossil' material is under the often thin veneer of grainy sand that seems to cover some of the wood like matter.
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5AMP		Posted : Friday, 22 June 2012 4:36:59 PM(UTC)
Rank: Gold Nugget Medals: Groups: Registered Joined: 3/11/2011(UTC) Posts: 57 Location: wellington Thanks: 105 times Was thanked: 16 time(s) in 11 post(s)		You have something rare and unusual there Simon.Do let us know when you find out what it is.