Geogrl13! Posted January 26, 2018 Share Posted January 26, 2018 Good afternoon friends, I was wondering if someone could kindly explain why the two trilobites I found at Mineral Wells Fossil Park around Dallas Texas fossilized so differently? The off white trilobite is extremely brittle and can easily crack, while the other was fossilized in stone. I just do not understand the fossilization process of the two. Thank you Mirna Villarreal The fossils are around 300 million years old Link to comment Share on other sites More sharing options...
Miocene_Mason Posted January 26, 2018 Share Posted January 26, 2018 Hopefully someone familiar with the site can confirm but this is my take: as you may know, fossils are usually the biological material replaced by minerals. In one case, it seems you have it preserved in a calcium carbonate rock (calcite or limestone or chalk) and in the other case something else, maybe a silica of some sort. They probably come from different stratigraphies, hence the different preservation. If any pieces of the white one have fallen off and your willing to put the piece in vinegar, it would bubble (If it is indeed calcium carbonate). “...whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been and are being evolved.” ~ Charles Darwin Happy hunting, Mason Link to comment Share on other sites More sharing options...
Fossildude19 Posted January 26, 2018 Share Posted January 26, 2018 @erose @BobWill @Uncle Siphuncle 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...
BobWill Posted January 27, 2018 Share Posted January 27, 2018 Whodaman has it right. Most fossils are a product of what minerals were present in the sediment and that is variable even at a single location but also at different times so it could be different at different stratigraphic levels. If two fossils erode out of a slope from different layers they could even be found right beside each other and still look very different. One may be limestone and the other phosphatized. Link to comment Share on other sites More sharing options...
ynot Posted January 27, 2018 Share Posted January 27, 2018 The difference could also be caused by the state of weathering, with the "crumbly" one being weathered longer. Darwin said: " Man sprang from monkeys." Will Rogers said: " Some of them didn't spring far enough." My Fossil collection - My Mineral collection My favorite thread on TFF. Link to comment Share on other sites More sharing options...
Geogrl13! Posted January 28, 2018 Author Share Posted January 28, 2018 On 1/26/2018 at 4:27 PM, Fossildude19 said: @erose @BobWill @Uncle Siphuncle I had been wondering about the fossil preservation for months and it all makes sense now. I am so thankful for you all taking the time to write back to me and I am happy to be on the forum. Thank you ynot,BobWill,Fossildude19 and WhodamanHD. Link to comment Share on other sites More sharing options...
Missourian Posted January 29, 2018 Share Posted January 29, 2018 It's hard to tell by the resolution of the photo, but it could be that the one on the bottom was preserved within a concretion (maybe ironstone/siderite), while the top one was in 'soft' shale, which would leave it less reinforced. Context is critical. Link to comment Share on other sites More sharing options...
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