bthemoose Posted November 23, 2021 Share Posted November 23, 2021 My wife and I spotted the large rock below yesterday along the shore of Lake Champlain in Shelburne, Vermont, and were intrigued by the light colored branching patterns. The rocks here are Ordivician in age. We're not sure whether these are fossils or not, but hopefully someone here can help. The pattern is flat/flush against the surface of the rock. Thanks in advance for your input! 2 Link to comment Share on other sites More sharing options...
Fossildude19 Posted November 23, 2021 Share Posted November 23, 2021 Branching bryozoans, I would think. 2 1 Tim - VETERAN SHALE SPLITTER VFOTM - APRIL - 2015 __________________________________________________ "In every walk with nature one receives far more than he seeks." John Muir ~ ~ ~ ~ ><))))( *> About Me Link to comment Share on other sites More sharing options...
Tidgy's Dad Posted November 23, 2021 Share Posted November 23, 2021 Very lovely section of 'bryozoan forest'. 1 Life's Good! Tortoise Friend. Link to comment Share on other sites More sharing options...
abyssunder Posted November 23, 2021 Share Posted November 23, 2021 It looks like a tracefossil, Chondrites. 3 2 " We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. " Thomas Mann My Library Link to comment Share on other sites More sharing options...
Rockwood Posted November 23, 2021 Share Posted November 23, 2021 All we have to go on is the gross morphology, but I'm convinced that this is not a bryozoan colony. The taper and fracture pattern is wrong. Notice how in a few spots one feature cuts through an existing one. More likely seen in burrowing I believe. 2 1 Link to comment Share on other sites More sharing options...
Fossildude19 Posted November 23, 2021 Share Posted November 23, 2021 7 minutes ago, Rockwood said: All we have to go on is the gross morphology, but I'm convinced that this is not a bryozoan colony. The taper and fracture pattern is wrong. Notice how in a few spots one feature cuts through an existing one. More likely seen in burrowing I believe. My only misgiving with the ichnological explanation is the differing color between the items and surrounding matrix. Usually, the colors are homogeneous and uniform. Tim - VETERAN SHALE SPLITTER VFOTM - APRIL - 2015 __________________________________________________ "In every walk with nature one receives far more than he seeks." John Muir ~ ~ ~ ~ ><))))( *> About Me Link to comment Share on other sites More sharing options...
abyssunder Posted November 23, 2021 Share Posted November 23, 2021 51 minutes ago, Fossildude19 said: My only misgiving with the ichnological explanation is the differing color between the items and surrounding matrix. Usually, the colors are homogeneous and uniform. I agree, but there are exeptions. Baucon et al., 2019 1 " We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. " Thomas Mann My Library Link to comment Share on other sites More sharing options...
Rockwood Posted November 23, 2021 Share Posted November 23, 2021 1 hour ago, Fossildude19 said: Usually, the colors are homogeneous and uniform. Not in a coral reef environment. All the available carbonate, ya know. Link to comment Share on other sites More sharing options...
Kane Posted November 23, 2021 Share Posted November 23, 2021 14 minutes ago, Rockwood said: Not in a coral reef environment. All the available carbonate, ya know. Not so. There are a number of reefal environments here in my early mid-Devonian strata where they are indeed homogeneous in colour (and particularly so in bituminous layers). Both types (hetero-/homogeneous colouration) can present depending on a number of taphonomic factors. ...How to Philosophize with a Hammer Link to comment Share on other sites More sharing options...
Rockwood Posted November 23, 2021 Share Posted November 23, 2021 1 hour ago, Kane said: Not so. Ya so. The argument was that in a coral reef environment they are not always homogeneous. As you just confirmed. Link to comment Share on other sites More sharing options...
Mark Kmiecik Posted November 23, 2021 Share Posted November 23, 2021 I see branching. Would a creature back up (beep, beep, beep) to try another direction or just keep moving forward? Mark. Fossil hunting is easy -- they don't run away when you shoot at them! Link to comment Share on other sites More sharing options...
Kane Posted November 23, 2021 Share Posted November 23, 2021 42 minutes ago, Rockwood said: Ya so. The argument was that in a coral reef environment they are not always homogeneous. As you just confirmed. Tim stated they are usually homogeneous. You said no. I confirmed they can be, and that both types present. As you stated: "Not in a coral reef environment," suggestive of an exclusive disjunction. ...How to Philosophize with a Hammer Link to comment Share on other sites More sharing options...
Rockwood Posted November 23, 2021 Share Posted November 23, 2021 15 minutes ago, Kane said: suggestive of an exclusive disjunction. Then you're saying that in a coral reef, such as the post likely is, trace fossils are usually homogenous ? Link to comment Share on other sites More sharing options...
Fossildude19 Posted November 23, 2021 Share Posted November 23, 2021 18 minutes ago, Rockwood said: Then you're saying that in a coral reef, such as the post likely is, trace fossils are usually homogenous ? No, he is saying they can be either. Just like you are. 1 Tim - VETERAN SHALE SPLITTER VFOTM - APRIL - 2015 __________________________________________________ "In every walk with nature one receives far more than he seeks." John Muir ~ ~ ~ ~ ><))))( *> About Me Link to comment Share on other sites More sharing options...
abyssunder Posted November 23, 2021 Share Posted November 23, 2021 (edited) 1 hour ago, Mark Kmiecik said: I see branching. Would a creature back up (beep, beep, beep) to try another direction or just keep moving forward? "The bedding plane expression of Chondrites is well-constrained by morphometry: (1) the angle of dichotomy formed by a pair of adjacent branches is typically between 30° and 56° (interquartile range; mean: 47°); (2) branching order is between 1 and 9; (3) branches are, on average, nine times longer than wide. In the third dimension, downward branching is dominant but bundled shafts and upward branching may be present." (...) "The tracemakers built Chondrites to obtain food: (1) vermiform deposit feeders produced Chondrites for searching for food in the sediment (fodinichnion); (2) asymbiotic bivalves built Chondrites for cultivating and directly ingesting bacteria (agrichnion); (3) chemosymbiotic bivalves produced Chondrites to provide symbionts with chemical agents. Chondrites was modified through the life of the tracemaker or it represented a part of the producer’s lifespan." - Baucon et al., 2019 Edited November 23, 2021 by abyssunder 7 " We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. " Thomas Mann My Library Link to comment Share on other sites More sharing options...
Mark Kmiecik Posted November 23, 2021 Share Posted November 23, 2021 Thank you, @abyssunder. I found that informative. 1 Mark. Fossil hunting is easy -- they don't run away when you shoot at them! Link to comment Share on other sites More sharing options...
Rockwood Posted November 23, 2021 Share Posted November 23, 2021 1 hour ago, Mark Kmiecik said: I see branching. Would a creature back up (beep, beep, beep) to try another direction or just keep moving forward? One crucial aspect here is that traces are not assigned to a single creature. They are rather structurally defined. Link to comment Share on other sites More sharing options...
Mark Kmiecik Posted November 23, 2021 Share Posted November 23, 2021 (edited) 1 hour ago, Rockwood said: One crucial aspect here is that traces are not assigned to a single creature. They are rather structurally defined. My feeble mind failed to consider the possibility of more than one architect. My bad. Edited November 23, 2021 by Mark Kmiecik fix typo Mark. Fossil hunting is easy -- they don't run away when you shoot at them! Link to comment Share on other sites More sharing options...
FranzBernhard Posted November 23, 2021 Share Posted November 23, 2021 Quite interesting, I took it for granted that this is some sort of "body fossils" However, inspecting the rather good pic closely, it seems, that the texture of the dark matrix and the bright branches is the same - ?? @bthemoose, what to you see/think, is there only a color difference between matrix and branches or also some textural difference (grain size etc.?) How does the specimen look like in side view? Is the pattern restricted to one bedding plane? Franz Bernhard Link to comment Share on other sites More sharing options...
bthemoose Posted November 23, 2021 Author Share Posted November 23, 2021 47 minutes ago, FranzBernhard said: Quite interesting, I took it for granted that this is some sort of "body fossils" However, inspecting the rather good pic closely, it seems, that the texture of the dark matrix and the bright branches is the same - ?? @bthemoose, what to you see/think, is there only a color difference between matrix and branches or also some textural difference (grain size etc.?) How does the specimen look like in side view? Is the pattern restricted to one bedding plane? Franz Bernhard The rock isn't in my possession so I can't inspect it further unfortunately. I'm not sure that collecting from this property is permitted (it's a privately owned, non-profit property that's open to the public) but this would have been far too large to carry home in any case. If I get back out to this spot on this trip I can try to take more photos and examine more closely. From memory, I believe that color was the main differentiator and I don't recall any textural differences. I don't think that I looked at the piece from the side. 1 Link to comment Share on other sites More sharing options...
kgbudge Posted November 23, 2021 Share Posted November 23, 2021 Not an expert -- there aren't any Ordovician beds within six hours of me, except possibly in the subsurface -- but my thought was trace fossils also. My Blog Link to comment Share on other sites More sharing options...
Ludwigia Posted November 23, 2021 Share Posted November 23, 2021 Here is a link to a Chondrites in my collection for visual comparison. 3 1 Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
abyssunder Posted November 24, 2021 Share Posted November 24, 2021 12 hours ago, Ludwigia said: Here is a link to a Chondrites in my collection for visual comparison. That's a very nice specimen, Roger! 1 2 " We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. " Thomas Mann My Library Link to comment Share on other sites More sharing options...
bthemoose Posted November 24, 2021 Author Share Posted November 24, 2021 Thanks for all the input, everyone! Link to comment Share on other sites More sharing options...
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