oneofmetwo Posted February 24, 2014 Share Posted February 24, 2014 (edited) I was sifting through some flaky sedimentary rock at the edge of the mountains of Pacoima, CA. There were very apparent layers of sedimentary rock exposed on the side of the hill/mountain. I did not find much, but every now and then found some very delicate and dark [carbon?] specimens. They are EXTREMELY delicate, and fracture at the slightest touch. The matrix is rather soft. The second was found in a narrow stratification of very sandy sedimentary rock. It looks insect like to me. Are these young specimens? Carbon 14 has a half-life of 5.7k years, so is this seemingly carbon leaf not very old? Roughly where I went hunting: 34°17'24"N 118°24'36"W (Those measurements are inches in the foreground and background) Edited February 24, 2014 by oneofmetwo Link to comment Share on other sites More sharing options...
painshill Posted February 24, 2014 Share Posted February 24, 2014 I don't know what it is, but there's a suggestion in your post that the decay of unstable Carbon-14 in relation to its half life means that a carbon film gradually disappears. It doesn't - to any appreciable extent. Carbon-14 is present at about 1 part per trillion in the atmosphere and becomes incorporated into organic structures in only small amounts relative to the larger amounts of the much more abundant and stable Carbon-12 isotope. As the small amount of Carbon-14 decays to Nitrogen-14, it has very little effect on the remaining overall carbon content of a fossil or other organic structure. What's left still looks like carbon, but it's the alteration in ratio of the two isotopes over time that enables us to date organic materials. 1 Roger I keep six honest serving-men (they taught me all I knew);Their names are What and Why and When and How and Where and Who [Rudyard Kipling] Link to comment Share on other sites More sharing options...
ashcraft Posted February 24, 2014 Share Posted February 24, 2014 looks like lignite to me fkaa ashcraft, brent allen Link to comment Share on other sites More sharing options...
Taogan Posted February 24, 2014 Share Posted February 24, 2014 Looks more like plant material to me Link to comment Share on other sites More sharing options...
ashcraft Posted February 24, 2014 Share Posted February 24, 2014 Is there a difference? fkaa? ashcraft, brent allen Link to comment Share on other sites More sharing options...
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