Apistos wanted to know where to find a fossil of love. As a paleontologist, that seemed like an appropriate challenge for me to take on.
Weâre going to the outcrop
And weâre going to get bur-ur-uried
Going to the fossil of love.
The photo here is just a quick shot with the phone, but it illustrates a fossil with a heart shape. Youâd have to mess with aspect ratios to make it very marketable as a Valentineâs card, but definitely r=k(1-cos(theta)) is a first approximation (especially if the left beak werenât broken; photo is upside down relative to the clam's anatomy and climatologically unlikely for the lower Pliocene but convenient for balancing the specimen). Additionally, although the fossil does not indicate this, examination of living relative shows that the clamâs heart was pierced. Admitting that itâs pierced by the intestine rather than by Cupidâs arrow may detract somewhat from the romance, however.
But, supposing that the request were spelled out clearly to indicate that what was wanted is fossil evidence of Godâs love for us, can we find evidence of that? A side view may help in telling more about this fossil.
An obvious question is whereâs the shell? This is an internal mold of a clam; why is the shell gone? That question leads into varied areas of crystallography, thermodynamics, and physical chemistry. The mold is made of calcite; the original shell was aragonite, two crystal forms of calcium carbonate.
What kind of shell was it? With left and right valves, over 5 cm in length, and two main muscles to hold the shell closed (evident from the muscle scars), this is a bivalve. Several different types of clues combine to indicate the taxonomy, once one gets used to how shell features shape molds. My MS thesis worked on another moldic fauna, so I have a fair amount of practice. Identification involves a combination of observing the features preserved and studying the publications about fossil and modern mollusks from the southeastern US. It is Glycymeris americana, but a peculiar specimen. The wrinkles are an unusual mutation (form âaberransâ). Some individuals have just wrinkles along the edge of each valve, near the beak, but this has extensive wrinkles. Normal specimens have no wrinkles at all. Whatâs going on genetically and physiologically behind this mutation? Is there a reason why there are other weird mutations appearing right about the same time, like left-handed whelks and cones or rib number variations in scallops? Maybe check the record of cosmogenic nucleotides for a nearby supernova around then.
When was then, anyway? The mutants have a brief period of high abundance and then disappear, while the normal form survives to the present. Sorting out the relative ages of deposits in the region is challenging. With sea level ups and downs as glaciers melt and expand, different patches got eroded away or preserved at different points. Local tectonic adjustments and continued ground movement due to the Eocene asteroid impact at whatâs now the mouth of the Chesapeake Bay also contribute complexity. Once again, itâs necessary to review the literature (and the reliability of those writing it) to figure out whatâs what. This specimen is upper Goose Creek Limestone, of mid-Pliocene age. Figuring out just how long ago that was takes one into radiometric dating, Milankovitch cycles, and correlations such as microfossils, land mammals, various stable isotopes, magnetic reversals, and more.
How does Glycymeris americana relate to other bivalves? Molecular phylogenetics can give us information, but it takes some sorting through by someone who knows what they are doing to figure out which sequences are correctly identified and useful to analyze, and to make sense of the results. Once again, a search through the literature, keeping the librarians busy, discovering a helpful bookseller with a copy of a Japanese publication rare in the US, putting in an online search for âhas anyone published about this group of clams?â, discovering that the name is also used for spiders, and sorting out that problem, is required to figure things out.
Wait, wasnât I supposedly looking for evidence of Godâs love rather than a chance to advertise some of the research my family and I have been doing for a few decades? But the countless possible fascinating areas for research are evidence of Godâs love. He has given us an amazing world to explore and care for, with a fascinating history of a few billion years so far, and thatâs just one small corner of a vast universe.
Of course, such a perception of Godâs love in a fossil reflects viewing it with the eye of faith. But no better agapometer exists.
