MarcoSr Posted February 15, 2021 Share Posted February 15, 2021 Oncolites are algae colonies that form spheres or oval shapes as differentiated from Stromatolites which are algae colonies forming cylindrical or tube shapes. I recently acquired three end cuts that contain large oncolite colonies. On average these oncolites measure between a half and three quarters of an inch on the longest axis (11mm to 19mm). Many of these colonies have been preserved in these end cuts with a bit of iron oxide. All three pieces are a polished end cut with cross sectioning of colonies on the cut and polished face and colonies weathering out on the all-natural back side. The oncolites are taxonomically identified as Girvanella sp. These pieces come from the Lower Cambrian Chambless Limestone Formation in San Bernardino County, California, most likely from lower (older) strata of the Chambliss Fm. All pictures were taken with the pieces dry; the end cut individual pictures by camera and the oncolite close-up pictures by digital microscope. End Cut 1 (1114g 120mm by 115mm by 45mm thick) End Cut 2 (486g 165mm by 85mm by 22mm thick) End Cut 3 (529g 120mm by 90mm by 32mm thick) Marco Sr. 6 "Any day that you can fossil hunt is a great day." My family fossil website Some Of My Shark, Ray, Fish And Other Micros My Extant Shark Jaw Collection Link to comment Share on other sites More sharing options...
FranzBernhard Posted February 15, 2021 Share Posted February 15, 2021 Very nice, thanks for sharing! Do you know what these abundant small, black things are? Could this be Trilo-bits? Franz Bernhard Link to comment Share on other sites More sharing options...
MarcoSr Posted February 15, 2021 Author Share Posted February 15, 2021 29 minutes ago, FranzBernhard said: Very nice, thanks for sharing! Do you know what these abundant small, black things are? Could this be Trilo-bits? Franz Bernhard The following excerpt is from a webpage by ucmp.berkeley.edu on the Marble Mountains: "The grayish layer above the Latham Shale, the Chambless Formation, is rich in oncolites, which are formed by cyanobacterial growth. Oncolites are very similar to stromatolites, but instead of forming columns, oncolites form nearly spherical growths. The image at lower left shows a slab of polished Chambless Limestone; the concentric "bull's-eye" pattern formed by algal growth is very apparent. The Chambless Formation is also rich in hyoliths and fragments of trilobites." Marco Sr. 1 "Any day that you can fossil hunt is a great day." My family fossil website Some Of My Shark, Ray, Fish And Other Micros My Extant Shark Jaw Collection Link to comment Share on other sites More sharing options...
MarcoSr Posted February 17, 2021 Author Share Posted February 17, 2021 A polished freshwater Oncolite { 214 grams 5 inches X 4 inches X .375 inches thick) from Lady of Angels Lake, Chihuahua, Mexico, Upper Cretaceous. Marco Sr. 1 1 "Any day that you can fossil hunt is a great day." My family fossil website Some Of My Shark, Ray, Fish And Other Micros My Extant Shark Jaw Collection Link to comment Share on other sites More sharing options...
Wrangellian Posted March 8, 2021 Share Posted March 8, 2021 Your pics of the Chambless oncolites are better than the others I've seen thus far! Make them more attractive. I'm curious about those conical sections in particular, and the line going through the red blob. Weird. Link to comment Share on other sites More sharing options...
MarcoSr Posted March 8, 2021 Author Share Posted March 8, 2021 5 hours ago, Wrangellian said: Your pics of the Chambless oncolites are better than the others I've seen thus far! Make them more attractive. I'm curious about those conical sections in particular, and the line going through the red blob. Weird. The end cuts from the Chambless Formation are polished which made the colors really stand out in the pictures. Plus a lot of the end cuts/slabs that I see from the Chambless formation don't have the yellow/red of these end cuts. I wish I knew more about the different fossils that are found in the Chambless Formation. I know trilobite fragments are very common and can also be seen in the pictures. Marco Sr. "Any day that you can fossil hunt is a great day." My family fossil website Some Of My Shark, Ray, Fish And Other Micros My Extant Shark Jaw Collection Link to comment Share on other sites More sharing options...
Wrangellian Posted March 9, 2021 Share Posted March 9, 2021 13 hours ago, MarcoSr said: The end cuts from the Chambless Formation are polished which made the colors really stand out in the pictures. Plus a lot of the end cuts/slabs that I see from the Chambless formation don't have the yellow/red of these end cuts. Well your pics are better than the pics I saw from the seller of that same material, polished and all. 1 Link to comment Share on other sites More sharing options...
MarcoSr Posted March 21, 2021 Author Share Posted March 21, 2021 A slab (5" x 7 1/4" x 1/4" thick weight 12 oz.) of Bird's Eye Marble from the Flagstaff Limestone from Thistle, Utah loaded with Eocene Oncolites. Marco Sr. 1 "Any day that you can fossil hunt is a great day." My family fossil website Some Of My Shark, Ray, Fish And Other Micros My Extant Shark Jaw Collection Link to comment Share on other sites More sharing options...
MarcoSr Posted April 4, 2021 Author Share Posted April 4, 2021 A polished slab (166 grams 3.5x4x.25 inches) from the Precambrian 720 to 740 Million yrs. old (Neoproterozoic) from the Beck Springs Limestone, Mohave Desert, California with oncolites: Marco Sr. 1 2 "Any day that you can fossil hunt is a great day." My family fossil website Some Of My Shark, Ray, Fish And Other Micros My Extant Shark Jaw Collection Link to comment Share on other sites More sharing options...
MarcoSr Posted April 15, 2021 Author Share Posted April 15, 2021 Two small slabs (25 grams 41x33x11 mm and 38 grams 62x32x13 mm) from the Carboniferous 358.9 to 298.9 million years ago from the Dunbar area, East Lothian, Scotland, UK with oncolites. Marco Sr. 1 "Any day that you can fossil hunt is a great day." My family fossil website Some Of My Shark, Ray, Fish And Other Micros My Extant Shark Jaw Collection Link to comment Share on other sites More sharing options...
Sjfriend Posted April 18, 2021 Share Posted April 18, 2021 That piece from the Beck Springs limestone is AWESOME! The colors and clarity is great. Link to comment Share on other sites More sharing options...
MarcoSr Posted April 19, 2021 Author Share Posted April 19, 2021 11 hours ago, Sjfriend said: That piece from the Beck Springs limestone is AWESOME! The colors and clarity is great. Thank you. The oncolites in that piece have a lot of detail. I have two different oncolite pieces in the mail from Australia. I'll post pictures hopefully in a week or two (international mail has been very erratic with Covid). Marco Sr. "Any day that you can fossil hunt is a great day." My family fossil website Some Of My Shark, Ray, Fish And Other Micros My Extant Shark Jaw Collection Link to comment Share on other sites More sharing options...
Wrangellian Posted April 19, 2021 Share Posted April 19, 2021 I like that one too. I've got a similar piece that was said to be from the Cambrian of what is now the Bristlecone Pine reserve. I've had it a while now but I should get a photo for comparison purposes. (I'm not thinking it's the same stuff, but similar - from a different fm/age but same neighborhood(?). Link to comment Share on other sites More sharing options...
MarcoSr Posted April 19, 2021 Author Share Posted April 19, 2021 6 hours ago, Wrangellian said: I like that one too. I've got a similar piece that was said to be from the Cambrian of what is now the Bristlecone Pine reserve. I've had it a while now but I should get a photo for comparison purposes. (I'm not thinking it's the same stuff, but similar - from a different fm/age but same neighborhood(?). Please post a photo. I've seen very small pieces of Bristlecone on the web but haven't bought any yet because I would like a bigger piece. See the below piece (length: 2.2” width: 1.9” thickness: .25”) Another piece that looks similar to the Beck Springs limestone piece: Marco Sr. "Any day that you can fossil hunt is a great day." My family fossil website Some Of My Shark, Ray, Fish And Other Micros My Extant Shark Jaw Collection Link to comment Share on other sites More sharing options...
Wrangellian Posted April 19, 2021 Share Posted April 19, 2021 4 hours ago, MarcoSr said: Please post a photo. I've seen very small pieces of Bristlecone on the web but haven't bought any yet because I would like a bigger piece. See the below piece (length: 2.2” width: 1.9” thickness: .25”) Another piece that looks similar to the Beck Springs limestone piece: Marco Sr. Are these both supposed to be from Bristlecone? Mine looks nothing like that first piece - more similar to your Beck Springs pieces, but maybe not identical. My slab is not polished but will photo it wet to simulate polish. Stay tuned.. Link to comment Share on other sites More sharing options...
MarcoSr Posted April 20, 2021 Author Share Posted April 20, 2021 11 hours ago, Wrangellian said: Are these both supposed to be from Bristlecone? Mine looks nothing like that first piece - more similar to your Beck Springs pieces, but maybe not identical. My slab is not polished but will photo it wet to simulate polish. Stay tuned.. Yes, but with a lot of sellers you can't really trust what they say. I see more pieces like the second piece (greenish with red oncolites) that I posted versus the first piece identified as Bristlecone. I bought my Beck Springs limestone piece from Dan Damrow probably the biggest seller/promoter of stromatolites nationwide who is extremely knowledgeable and self collected most of his pieces. Marco Sr. "Any day that you can fossil hunt is a great day." My family fossil website Some Of My Shark, Ray, Fish And Other Micros My Extant Shark Jaw Collection Link to comment Share on other sites More sharing options...
Wrangellian Posted April 20, 2021 Share Posted April 20, 2021 (edited) Ah... Here is mine. Now that I see it wet it looks much more like yours than I thought. I've learned that I need to take a seller's ID with a grain of salt, so I wasn't sure about mine. Are you saying that your piece similar to this one was ID'd as Beck Springs, with high confidence? Edited April 20, 2021 by Wrangellian Link to comment Share on other sites More sharing options...
MarcoSr Posted April 21, 2021 Author Share Posted April 21, 2021 On 4/20/2021 at 8:34 AM, Wrangellian said: Ah... Here is mine. Now that I see it wet it looks much more like yours than I thought. I've learned that I need to take a seller's ID with a grain of salt, so I wasn't sure about mine. Are you saying that your piece similar to this one was ID'd as Beck Springs, with high confidence? Really nice piece. My latest book on stromatolites Leis, Stinchcomb, Mckee, 2015, Stromatolites Ancient, Beautiful, and Earth-Altering mentions Dan Damrow specifically as "perhaps the greatest purveyor of stromatolites nationwide". The author also states "I have obtained many fine specimens from him." So I do trust Dan's data on the Beck Springs Limestone piece that I purchased from him. However, that doesn't mean that your piece couldn't be Bristlecone even though it does look so similar to mine. I see a lot of interesting looking stromatolites on the web that I don't purchase because the sellers really don't have much data on the pieces and usually bought the pieces from someone else. Dan collected himself a lot of the pieces that he sells and cuts the slabs and polishes them himself. Edit: I sent a picture of your piece to Dan Damrow and he replied back "The material has numerous locations in the Mohave and I have mine provided by a scientist who worked there and on my fossil jellyfish site. He provided me with all the documentation on the site and age. The material online is being offered and was collected on reservation lands but is the same material.' Marco Sr. "Any day that you can fossil hunt is a great day." My family fossil website Some Of My Shark, Ray, Fish And Other Micros My Extant Shark Jaw Collection Link to comment Share on other sites More sharing options...
Wrangellian Posted April 21, 2021 Share Posted April 21, 2021 (edited) 13 hours ago, MarcoSr said: Really nice piece. My latest book on stromatolites Leis, Stinchcomb, Mckee, 2015, Stromatolites Ancient, Beautiful, and Earth-Altering mentions Dan Damrow specifically as "perhaps the greatest purveyor of stromatolites nationwide". The author also states "I have obtained many fine specimens from him." So I do trust Dan's data on the Beck Springs Limestone piece that I purchased from him. However, that doesn't mean that your piece couldn't be Bristlecone even though it does look so similar to mine. I see a lot of interesting looking stromatolites on the web that I don't purchase because the sellers really don't have much data on the pieces and usually bought the pieces from someone else. Dan collected himself a lot of the pieces that he sells and cuts the slabs and polishes them himself. Edit: I sent a picture of your piece to Dan Damrow and he replied back "The material has numerous locations in the Mohave and I have mine provided by a scientist who worked there and on my fossil jellyfish site. He provided me with all the documentation on the site and age. The material online is being offered and was collected on reservation lands but is the same material.' Marco Sr. Thanks for doing that. Just so I'm clear, he's saying my piece is Beck Springs material, even if it is from Bristlecone? - same age as yours, <700my? The info provided me was that this piece is Cambrian in age (and "White-Inyo Mtns, north of Death Valley, now the Bristlecone Pine reserve"), but as we know, sellers don't always know what they're dealing in. I guess I need to see a geological map of the area (though that might not clear anything up). Edited April 21, 2021 by Wrangellian Link to comment Share on other sites More sharing options...
MarcoSr Posted April 22, 2021 Author Share Posted April 22, 2021 10 hours ago, Wrangellian said: Thanks for doing that. Just so I'm clear, he's saying my piece is Beck Springs material, even if it is from Bristlecone? - same age as yours, <700my? The info provided me was that this piece is Cambrian in age (and "White-Inyo Mtns, north of Death Valley, now the Bristlecone Pine reserve"), but as we know, sellers don't always know what they're dealing in. I guess I need to see a geological map of the area (though that might not clear anything up). That is what his e-mail reply stated. Checking geological maps is a way to try to verify age. Only death and taxes are 100% certain. Marco Sr. "Any day that you can fossil hunt is a great day." My family fossil website Some Of My Shark, Ray, Fish And Other Micros My Extant Shark Jaw Collection Link to comment Share on other sites More sharing options...
Wrangellian Posted April 22, 2021 Share Posted April 22, 2021 OK thanks, that's interesting. Another label to redo... Lost one Cambrian oncolite, gained a Precambrian one! Right now there is a piece of Mojave Desert stromatolite at the usual venue, but I asked the seller for more info on it but got no reply. Your guy found a jellyfish site, somewhere in the SW? I'd like to know more about that... Link to comment Share on other sites More sharing options...
Wrangellian Posted April 22, 2021 Share Posted April 22, 2021 I've been trying to find more info about this material online. Not much out there about this material from the Beck Spring Dolomite (not Beck Springs Limestone, apparently)..... Not even sure they're oncoids as I saw mention of some "giant ooids" in the BSD [called pisoliths according to wikipedia]. And the age range for the BSD is variously given as 780-730my, 780-717, etc. Link to comment Share on other sites More sharing options...
MarcoSr Posted April 23, 2021 Author Share Posted April 23, 2021 4 hours ago, Wrangellian said: I've been trying to find more info about this material online. Not much out there about this material from the Beck Spring Dolomite (not Beck Springs Limestone, apparently)..... Not even sure they're oncoids as I saw mention of some "giant ooids" in the BSD [called pisoliths according to wikipedia]. And the age range for the BSD is variously given as 780-730my, 780-717, etc. Check out the PDF of the paper Smith 2015 Tectonostratigraphic evolution of the c. 780-730 Ma Beck Spring Dolomite: Basin Formation in the core of Rodinia at the below link: https://www.researchgate.net/publication/277977459_Tectonostratigraphic_evolution_of_the_c_780-730_Ma_Beck_Spring_Dolomite_Basin_Formation_in_the_core_of_Rodinia The below figure 7 is from that paper: Fig. 7. Sedimentary features of the Beck Spring Dolomite. Locations of photos in the Kingston Range, Saddle Peak Hills, and Saratoga Springs are marked with white triangles in Figures 3 and 4. (a) Quartz pebble to cobble conglomerate in the upper part of the Beck Spring Dolomite in west-central Saddle Peak Hills. (b) Soft sediment deformation in KP1 in southern Saddle Peak Hills. (c) Molar tooth structure in top of the Beck Spring Dolomite at Saratoga Springs. Photograph taken north of measured section. (d) Oncoids at the top of the Beck Spring Dolomite sampled from the fault block in western Beck Canyon. (e) Giant, partially silicified ooids in the top of the Beck Spring Dolomite in western Saddle Peak Hills. (f ) White line outlines cross-sectional view of Beck Spring Dolomite sand grykes that are in-filled with the overlying Surprise diamictite in Surprise Canyon, Panamint Mountains. You can see in Figure 7 (d) oncoids. Oncolites are sedimentary structures composed of oncoids, which are layered structures formed by cyanobacterial growth. Also the top of the Beck Spring Dolomite where the oncoids are found would be around 730 ma which is within the 720 to 740 ma range that Dan gave me. You can see in Figure 7 (e) giant partially silicified ooids. So both oncolites and ooids can be found in the Beck Spring Dolomite. I also read in another USGS publication that parts of the Beck Spring were dolomitic limestone. Limestone is made of calcium carbonate. Dolomite is made of calcium magnesium carbonate. Marco Sr. "Any day that you can fossil hunt is a great day." My family fossil website Some Of My Shark, Ray, Fish And Other Micros My Extant Shark Jaw Collection Link to comment Share on other sites More sharing options...
Wrangellian Posted April 23, 2021 Share Posted April 23, 2021 I saw that but couldn't download the paper (I should sign up for that site... I guess that's next). I was only going by the references I saw which called it the B.S. Dolomite as the name of the formation. Yes, I read that it has both oncolites and oolites but I haven't seen any solid info that shows our cm-scale oncolites as coming from the BSD. The ones in the above figure appear to be much larger than ours. Not an obvious match. Anyway I'll take your guy's word for it if he is as reliable as he seems. I still want to see a geo map of the Bristlecone reserve area, for my own edification. Link to comment Share on other sites More sharing options...
MarcoSr Posted April 29, 2021 Author Share Posted April 29, 2021 A slab with oncolites from the Miocene (15 million years old) Trealla Limestone from north of Carnarvon, Western Australia (148grams 125 x75x7mm) Marco Sr. 1 "Any day that you can fossil hunt is a great day." My family fossil website Some Of My Shark, Ray, Fish And Other Micros My Extant Shark Jaw Collection Link to comment Share on other sites More sharing options...
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