Steph Posted April 25, 2023 Share Posted April 25, 2023 Hi, I have some beach specimens to explore and ID, but I’m having trouble determining the geologic age to know where to start. Can age be determined for specimens washed ashore (or could they potentially have arrived from anywhere)? Perhaps the maps/surveys makes the answer obvious, but I’m still confused and curious. My location of interest (green arrows) is labeled as ‘undetermined’ on the 1st pic. Screenshot is subpar, but that is how the site looks on my phone). The last pic is an example of my specimens. Grateful for your help. Steph Link to comment Share on other sites More sharing options...
Shellseeker Posted April 26, 2023 Share Posted April 26, 2023 Well, Steph, an easy question to ask and almost impossible question to answer... What is geo age of Florida Gulf Coast? I was a Computer Engineer in some previous existence... I am not a scientist, I am not a geologist, I am a fossil hunter... because I am interested in hunting fossil on the Gulf Coast of Florida, I hear some tidbits of info that relate to your questions.. 1) Florida came out of the primordial seas about 48 million years ago during the Eocene. See how much that cuts away.. We only have to be concerned about the last 6 Geologic ages Eocene to now. 2) As the picture indicates, any current land mass (like the Gulf Coast) is made up of layers or Formations that were dropped on top of the older formations during each Geologic Age.. and within each layer are lots of fossils and many geologic elements, sands, mud, rock, etc and the layers contain seashells and mammal remains that are good ways to "date" a layer. The oldest fossils that I have found go back to the Miocene, and most of my fossil hunting have happened on Florida's Gulf Coast. 3) If you go a foot or a couple of miles from the current Gulf Coast and Dig down until you find bedrock and the original ocean bottom, you will find the layers, from most to least recent. The layers contain fossils, like seashells, Mammal teeth and bones. Date the fossil and you date the layer. 4) So I find fossils of Invertebrates (Seashells) and animal teeth, bones, etc from creatures that alive back to the Miocene.... I would date the Geologic age of the Gulf Coast occurring sometime between the Eocene and Miocene. 5) The area of North Florida and Panhandle came out of the waters earlier than the area of southern Florida. We can find some Oligocene Formations and layers with fossils of seashells, echinoids, and even mammal remains . You seem to be interested in the Green Arrows and the answer to the answer to the question might be approximated as the Oligocene. As I look at your example find, it seems you have some congealing of mud, sands, clays, dolamite, and shell material !!! If the shells could be identified, they would be dated to a specific Geologic age. 11 hours ago, Steph said: Can age be determined for specimens washed ashore (or could they potentially have arrived from anywhere)? As above, you date what is contained in your specimen, and sometimes that is possible and sometimes not... and over million of years , contamination is always possible. Let me pause there and hope other members chime in to correct my errors... jack The White Queen ".... in her youth she could believe "six impossible things before breakfast" Link to comment Share on other sites More sharing options...
Steph Posted April 28, 2023 Author Share Posted April 28, 2023 On 4/25/2023 at 10:19 PM, Shellseeker said: Well, Steph, an easy question to ask and almost impossible question to answer... What is geo age of Florida Gulf Coast? I was a Computer Engineer in some previous existence... I am not a scientist, I am not a geologist, I am a fossil hunter... because I am interested in hunting fossil on the Gulf Coast of Florida, I hear some tidbits of info that relate to your questions.. 1) Florida came out of the primordial seas about 48 million years ago during the Eocene. See how much that cuts away.. We only have to be concerned about the last 6 Geologic ages Eocene to now. 2) As the picture indicates, any current land mass (like the Gulf Coast) is made up of layers or Formations that were dropped on top of the older formations during each Geologic Age.. and within each layer are lots of fossils and many geologic elements, sands, mud, rock, etc and the layers contain seashells and mammal remains that are good ways to "date" a layer. The oldest fossils that I have found go back to the Miocene, and most of my fossil hunting have happened on Florida's Gulf Coast. 3) If you go a foot or a couple of miles from the current Gulf Coast and Dig down until you find bedrock and the original ocean bottom, you will find the layers, from most to least recent. The layers contain fossils, like seashells, Mammal teeth and bones. Date the fossil and you date the layer. 4) So I find fossils of Invertebrates (Seashells) and animal teeth, bones, etc from creatures that alive back to the Miocene.... I would date the Geologic age of the Gulf Coast occurring sometime between the Eocene and Miocene. 5) The area of North Florida and Panhandle came out of the waters earlier than the area of southern Florida. We can find some Oligocene Formations and layers with fossils of seashells, echinoids, and even mammal remains . You seem to be interested in the Green Arrows and the answer to the answer to the question might be approximated as the Oligocene. As I look at your example find, it seems you have some congealing of mud, sands, clays, dolamite, and shell material !!! If the shells could be identified, they would be dated to a specific Geologic age. As above, you date what is contained in your specimen, and sometimes that is possible and sometimes not... and over million of years , contamination is always possible. Let me pause there and hope other members chime in to correct my errors... jack Hi Jack, Thank you so much for sharing your approach to my question. I now have a logic approach I can use and a much better understanding of why my question was not straightforward. As I’m sure you surmised, I’m a total newbie and I am still piecing together some concepts. Your logical approach helped organize a lot of loose ideas that I was aware of, but needed to better connect (eg the concept of bedrock). My local area is Paleozoic so the the types of fossils and rocks are so different! Thanks again for your response I’m definitely saving the paleo nerds diagram. Since you like to hunt in the Gulf, for fun, I’ll share a couple of other Spring Break finds. I found this fish vertebrae while looking for micro shells Not sure if it is a fossil Crab claw - old and friable, but I’m guessing it isn’t a fossil because it is hollow More interesting rocks that appear to have trace fossil imprints. I’m not sure about this one. Initially, thought it was a weathered shell fragment, but I don’t typically see shells weather like this - instead, most seem to get smoother and ribs get less pronounced rather than the area between the ribs weathering first. And finally, since you are @Shellseeker, I’ll share a sample of my micro shells Happy Hunting! Steph Link to comment Share on other sites More sharing options...
Al Dente Posted April 28, 2023 Share Posted April 28, 2023 4 hours ago, Steph said: I’m not sure about this one. Initially, thought it was a weathered shell fragment, but I don’t typically see shells weather like this - instead, most seem to get smoother and ribs get less pronounced rather than the area between the ribs It looks like a barnacle plate. 1 Link to comment Share on other sites More sharing options...
FossilDAWG Posted April 28, 2023 Share Posted April 28, 2023 I agree, definitely a barnacle plate. Don 1 Link to comment Share on other sites More sharing options...
Recommended Posts