daddio Posted July 22, 2016 Author Share Posted July 22, 2016 #3 Link to comment Share on other sites More sharing options...
Fossildude19 Posted July 22, 2016 Share Posted July 22, 2016 Very Cool! Regards, 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...
daddio Posted June 23, 2017 Author Share Posted June 23, 2017 Todays Finds 6/22/17 ( Brooksella's Link to comment Share on other sites More sharing options...
Fossildude19 Posted June 23, 2017 Share Posted June 23, 2017 Nice! Thanks for posting these - I enjoy seeing these. Regards, 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...
piranha Posted June 23, 2017 Share Posted June 23, 2017 Previously in this thread I posted the citation for the paper describing Brooksella as a sponge. A few months later this new information was presented at GSA. I posted this update in another thread on TFF, but forgot about this thread until now. Evidently Brooksella is not a sponge. Better late than never! RE-EVALUATION OF THE MIDDLE CAMBRIAN SPONGE, BROOKSELLA ALTERNATA, FROM THE CONASAUGA FORMATION, GEORGIA AND ALABAMA, U.S.A Paper No. 162-13 - Monday, 26 September 2016: 9:00 AM-6:30 PM Nolan, Morrison, Department of Geology, University of Georgia, 210 Field Street, Athens, GA 30602, Walker, Sally E., Department of Geology, University of Georgia, Athens, GA 30602 and Sharma, Ajay, Veterinary Biosciences & Diagnostic Imaging, University of Georgia, 501 D.W. Brooks Drive, Athens, GA 30602 The identity of Brooksella alternata has fascinated paleontologists since Charles Walcott described the alleged fossils along the Conasauga River in Georgia and Alabama. Walcott thought Brooksella was a medusoid jellyfish; later workers suggested a feeding or gas bubble trace, and more recently, a hexactinellid sponge. We re-examined the evidence that Brooksella was a sponge that possessed radial canals, oscula, ostia, and hexactinellid spicules. These features were previously reported as external and internal radial lobes, a central depression, surface pores, and an external meshwork of spicules, respectively. Surface morphologic features of Brooksella (n = 72) were observed and measured (body diameter, lobe length and width, osculum diameter). Internal morphology was examined with computed tomography and XRD analysis was used to determine Brooksella’s composition. Thin sections were microprobed to identify mineral associations and to look for spicules. We also collected in situ Brooksella to determine whether its orientation in the shales was consistent with a living sponge. Results indicate that Brooksella is highly variable in morphology, especially in the number of lobes, ranging from 3 to 15. Some lobes were well defined, others not; none had a canal opening or internal canals as previously reported, suggesting they might not be radial canals. Some specimens have a central protuberance rather than a depression, or lacked a central depression all together, calling into question whether they had oscula. Small surface pits were made by lichen and small rootlets, and were likely not ostia. Hexactinellid spicules or traces were not present on the surface or in thin sections. Brooksella’s composition and internal structure are similar to concretions from the Conasauga: quartz grains with minor amounts of calcite and small, oxidized, root-like holes partly filled with iron oxide and barite crystals. In situ Brooksella were rare and were oriented with their “oscula” and lobes downward, rather than upward if this was a once-living sponge. Furthermore, shale laminations were displaced by the growth of the putative sponge. We therefore think that the sponge designation is insufficiently supported, and we favor a concretional mode of formation for Brooksella. 4 Link to comment Share on other sites More sharing options...
Wrangellian Posted June 23, 2017 Share Posted June 23, 2017 Concretions! That's disappointing. Well, they are interesting for a concretion.. Link to comment Share on other sites More sharing options...
Plantguy Posted June 24, 2017 Share Posted June 24, 2017 "and we favor a concretional mode of formation for Brooksella". The word favor makes this interesting..I'm gonna go have to read some more about it. I wouldnt stop collecting them...they are too cool. Thanks for showing all the photos...Not sure where I was when you originally posted the finds. Regards, Chris 1 Link to comment Share on other sites More sharing options...
piranha Posted June 24, 2017 Share Posted June 24, 2017 13 hours ago, Plantguy said: "and we favor a concretional mode of formation for Brooksella". The word favor makes this interesting..I'm gonna go have to read some more about it. My money is on Seilacher's interpretation. text from: Seilacher, A., & Gishlick, A.D. (2015) Morphodynamics. CRC Press, 514 pp. Another medusiform fossil, Brooksella cambria from Alabama, illustrates how diagenetic overprints (Pl. 7.4) can irritate. It is actually a complex burrow (i.e., trace fossil) in which a central shaft was surrounded by U-shaped probes as indicated by seleniform backfill lamellae (seen only in rare specimens). The probes became protrusively displaced, probably by a worm-like sediment feeder. Without such details, these fossils could be mistaken for sand corals, because the burrows induced the sediment around (in this case mud rather than sand) to harden in a concretionary manner. Remember, growth follows the pneu principle, whether in a jellyfish, a sand coral, or a diagenetic concretion. 2 Link to comment Share on other sites More sharing options...
FossilDAWG Posted June 25, 2017 Share Posted June 25, 2017 I also favor Seilacher's interpretation, which is not inconsistent with the Norris abstract. Basically, feeding traces nucleated concretion formation, but the concretions grew beyond the limits of the original feeding tracts or probes into the sediment to encompass the surrounding sediment. Any organic material, such as hexactinellid spicules, that happened to be in the sediment near the feeding trace could be incorporated into the growing concretion. I gave Dr. Walker a Brooksella specimen that has a complete trilobite on its surface. This specimen demonstrates nicely, I think, that Brooksella has commonalities with other concretions that are abundant in the Conasauga Shale and are well known to sometimes "capture" trilobites. By "capture" I mean that these concretions do not grow specifically around the trilobites, but rather that they started around some other random trigger in the sediment (such as burrows/trace fossils) and cement together a lump of sediment including whatever happened to be in the near vicinity. This is why the trilobites are on the surface or sticking out of the concretions, instead of being found at the center. Concretion formation must have happened very quickly, because the same trilobites are found in/on concretions and in the surrounding shale, but the specimens in/on concretions are completely 3-dimensional and the shale specimens are highly flattened. Don 3 Link to comment Share on other sites More sharing options...
doushantuo Posted June 25, 2017 Share Posted June 25, 2017 link 2 Link to comment Share on other sites More sharing options...
doushantuo Posted June 25, 2017 Share Posted June 25, 2017 older piece: palo.2005.p05-109r (1).pdf 2 Link to comment Share on other sites More sharing options...
doushantuo Posted June 25, 2017 Share Posted June 25, 2017 link (I guesspect* underground CO2 storage possibilities has something to do with the research effort) 2 Link to comment Share on other sites More sharing options...
doushantuo Posted June 25, 2017 Share Posted June 25, 2017 yep,but not like I thought(co2 enhanced hydrocarbon extraction: 1 Link to comment Share on other sites More sharing options...
Plantguy Posted June 26, 2017 Share Posted June 26, 2017 Thanks guys! Regards, Chris Link to comment Share on other sites More sharing options...
daddio Posted July 15, 2017 Author Share Posted July 15, 2017 Found a Nice Brooksella today, all pics are of the same Brooksella :-) The search goes on. 1 Link to comment Share on other sites More sharing options...
FossilDiva#1 Posted July 28, 2018 Share Posted July 28, 2018 Those Brooksella's are awesome!!! I think they are VERY kool! You are very lucky to have them on your driveway!! Im hoping to find some this coming winter when i come that way! We have Megs and Angys all over here in the neighborhood , i have plenty of them , but now i want some new fossils . Link to comment Share on other sites More sharing options...
FossilDiva#1 Posted July 28, 2018 Share Posted July 28, 2018 On 5/27/2016 at 11:37 PM, daddio said: They just wash up no creek near. every time we have a real hard downpour I walk the long drive searching for them. On 6/7/2016 at 9:27 PM, daddio said: These are todays finds Those are really neat fossils! Link to comment Share on other sites More sharing options...
Nimravis Posted July 28, 2018 Share Posted July 28, 2018 @David Schwimmer FYI Link to comment Share on other sites More sharing options...
Cheryl 55 Posted July 31, 2018 Share Posted July 31, 2018 It is interesting that your Brooksellas wash up out of the ground. I joined this group to find out what kind of fossil was in some of the rocks used in my 80-year-old rock house. My Brooksellas are about 4" across and still attached to the rock. These are supposed to be the results of something feeding in the sand or mud? Link to comment Share on other sites More sharing options...
Ludwigia Posted July 31, 2018 Share Posted July 31, 2018 Very cool. Your driveway must have been a sort of reef back in the Cambrium. Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
FossilDiva#1 Posted July 31, 2018 Share Posted July 31, 2018 Wow! Thats pretty kool! I think there neat either way. As singles or insitu. Link to comment Share on other sites More sharing options...
FossilDiva#1 Posted July 31, 2018 Share Posted July 31, 2018 (edited) This is what mine looks like that i found last week. Im not 100 percent that it is one, but i found the consauga formation and it was washed out right near it. Edited July 31, 2018 by FossilDiva#1 Link to comment Share on other sites More sharing options...
Cheryl 55 Posted July 31, 2018 Share Posted July 31, 2018 How exciting! I would love to have some of the separated ones! My house is 80 years old and I have no idea where the rocks came from. I'm in the Ozark mountains of Arkansas so I'm curious about the origin of the rocks. With as many local rocks as we have it seems highly unlikely the builder would have bought rocks from Alabama, though. I might contact a geologist from the University of Arkansas. Link to comment Share on other sites More sharing options...
piranha Posted July 31, 2018 Share Posted July 31, 2018 4 hours ago, Cheryl 55 said: It is interesting that your Brooksellas wash up out of the ground. I joined this group to find out what kind of fossil was in some of the rocks used in my 80-year-old rock house. My Brooksellas are about 4" across and still attached to the rock. These are supposed to be the results of something feeding in the sand or mud? This is not Brooksella. Instead, this is the trace fossil: Asterosoma radiciforme 2 Link to comment Share on other sites More sharing options...
Cheryl 55 Posted August 1, 2018 Share Posted August 1, 2018 Ok, thank you! So, Brooksellas are the fossils of sponges and are usually separate, loose fossils, and what I have are trace fossils of something feeding in the mud. Are they from the same time period, or are the trace fossils newer? Link to comment Share on other sites More sharing options...
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