Team GotQuestions Blog

a Blog for Sharing Stories, Tips & Encouragement

On Rudistids (fossils of clams)

September 15th, 2014

What are Rudistids? They are a class of long extinct clams. Their form is bizarre in that most of them look more like corals, depending on the type of rudist (and there are many types). Why have I taken a fancy to them? A combination of reasons: 1) where I once lived they were easy to find on fossil hunting expeditions, 2) they make attractive specimens adorning my collection, 3) they are quite important to the oil business in terms of age-dating and in recognizing depositional environments (some rudists grew in reefs, others in quiet water lagoons, others along the shoreface, etc.). Some young Earth proponents believe that the fossil record is a mish-mash of debris with its layering governed by flood hydrodynamics. I would shout this from the rooftops if it was true – but it isn’t. The fossil record around the world displays a consistent sequential ordering that has nothing to do with Noah’s Flood, and as I have said many times before, this is not to cast doubt on the biblical account of the Flood. Blessings!

What are Rudistids? They are a class of long extinct clams. Their form is bizarre in that most of them look more like corals, depending on the type of rudist (and there are many types). Why have I taken a fancy to them? A combination of reasons: 1) where I once lived they were easy to find on fossil hunting expeditions, 2) they make attractive specimens adorning my collection, 3) they are quite important to the oil business in terms of age-dating and in recognizing depositional environments (some rudists grew in reefs, others in quiet water lagoons, others along the shoreface, etc.). Some young Earth proponents believe that the fossil record is a mish-mash of debris with its layering governed by flood hydrodynamics. I would shout this from the rooftops if it was true – but it isn’t. The fossil record around the world displays a consistent sequential ordering that has nothing to do with Noah’s Flood, and as I have said many times before, this is not to cast doubt on the biblical account of the Flood. Blessings!
  • Robert Lowry Steve, why would the AGE of fossils matter to oil exploration? I understand how depositional features would matter to finding oil, but why is age of fossils important? I did some consulting work sometime back for a major oil company (related to how electronic components in downhole drilling equipment survived the heat and pressures in the wellbore), and the geologists I worked with never mentioned any interest in age of the deposits they were exploring.
    Yesterday at 6:47am · Like
  • Steve Ray Webb Wow, Robert! Age is just critical to what we do. There is not a single day of my working life that we are not talking about rock ages. There is probably not even an hour that I don’t say something about a rock age. It is what provides our entire working framework! It is the daily language that we speak. The reason is that for a given basin (the Rajasthan Basin at present for me) (and tremendously simplified), is that the different age rocks have crucially important dissimilar characteristics. Here, the Paleocene (Barmer Hill Formation) has the most important source rocks and the Eocene (Fatehgarh Formation) has the most important reservoir rocks. If one were to just drill randomly there is a 98% chance you would not only miss one of these but both of them because they have different distributions and neither is present throughout the entire basin. In addition certain volcanic rocks here are interesting in that they are forming gas reservoirs, but ONLY the volcanics that are Cretaceous age (the Deccan Volcanics). The trouble is that these volcanics visually appear similar to Proterozoic volcanics that are also present in the basin but the Proterozoic lack both reservoir quality and a viable source. It is crucial that we age date these rocks so that we can map and understand their areal distributions. I could drone on for pages but please understand that I am not unusual in this regard. This is part and parcel of what we do. We would be pretty hopeless at finding oil and gas without this knowledge and I do not exaggerate.
    Yesterday at 7:08am · Like · 1
  • Elizabeth DeVore Doesn’t matter how old they are. I’d still be allergic.
    Yesterday at 8:35am · Like · 2
  • Steve Ray Webb Elizabeth DeVore, the original shell material of some of these rudists was made of aragonite rather than the usual calcite, another interesting aspect about them. Such a difference may well have translated itself to having a very different body chemistry. Who knows, you may have been able to eat the Toucasids. Perhaps we will be able to enjoy them at a BBQ in the New Creation!
    Yesterday at 8:54am · Like · 2
  • Robert Lowry Aren’t you talking about relative ages? I can see how one source rock that is thought to be relatively older than another source rock might be used to predict presence or absence of oil, based on earlier successes or failures with that kind of rock. But if I understand it correctly, that does not use absolutel ages. That takes radiogenic dating. And that is notoriously inaccurate. In fact, and again if I understand it correctly, radiogenic dating of rock is based on age of fossils. But then, the whole methodology turns around and dates fossils based on age of rocks. It’s circular reasoning. There are no absolute calibration standards for the various radiogenic measurements that are totally unrelated to the materials being dated.
    19 hrs · Like · 2

Team GotQuestions Blog

a Blog for Sharing Stories, Tips & Encouragement