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Do you know of any cave systems within Mesozoic vertebrate-bearing limestones?
Paleoworld-101 posted a topic in Questions & Answers
A bit of a random question, but i was watching a couple videos about some of the biggest cave systems on earth, and it got me thinking that almost all of the major cave systems i know about are formed by running water slowly etching away passages within Palaeozoic (or older) marine limestones. The walls of these caves usually contain a range of marine invertebrate fossils such as corals, crinoids, stromatoporoids etc. However, there are seemingly much fewer natural cave systems that run through younger limestones (Mesozoic or Cenozoic) containing vertebrate fossils within their walls. What are some examples that people here are familiar with? I'm not talking about instances where the cave system formed first, and then vertebrates later entered the caves and became trapped, causing their bones to accumulate within the caverns (e.g., like at Naracoorte Caves and on the Nullarbor Plain in Australia). I'm specifically talking about instances where limestone deposits containing vertebrate fossils were already laid down, and then afterwards, a natural cave system was subsequently formed through the bone-bearing limestones. I'm also not talking about artificial 'caves' or tunnels formed by human mining or digging operations. I did some googling and found both the Malaval Cave and Castelbouc Cave systems in France, which contain Earliest Jurassic and Middle Jurassic dinosaur footprints, respectively: https://digitalcommons.usf.edu/ijs/vol47/iss1/3/ https://www.tandfonline.com/doi/abs/10.1080/02724634.2019.1728286?journalCode=ujvp20 There is also Riversleigh in Queensland, Australia, which has some caves carved out of Miocene limestones containing the fossils of marsupials, bats, birds and reptiles. What others are there? Do any natural caves contain dinosaur or marine reptile bones within their walls?- 1 reply
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- cave fossils
- caves
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Before talking about the fossils, let me give you some background on the caves of Meghalaya (Northeast India). Since 1992, annual expeditions by European and US cavers, mapped more than 300 kms of cave passages in numerous caves. The exploration is supported locally by the Meghalaya Adventurers Association as a part of the “Abode of the Clouds Project”. I have been to India five times so far. During December 2012 expedition to the West Khasi Hills, Meghalaya, a 5-member exploration team from Meghalaya and the US explored a spectacular river cave, Krem Amarsang (krem=cave in the local Khasi language), formed in Siju Limestone Formation. The cave entrance (360m asl), located deep in the jungle, is adorned with stone pendants, and leads steeply over large boulders to a lower gallery where a stream emerges from under the breakdown. The cave is decorated with large rust-colored flowstone curtains, rimstone dams as well as stalagmites and stalactites. Uniquely, much of the course of the underground river follows a succession of symmetrical dissolutional potholes with diameters often exceeding three meters indicating substantial volume and velocity of water. Margins where consecutive potholes meet form razor sharp edges. Beyond the second 3-meter waterfall, the river passage bifurcates. The cave was partly mapped (length = 743m; depth = -40m) with both river passages continuing with no end in sight. Horseshoe bats, fish, crayfish, snails, spiders, and crickets were observed. In this context, the Eocene Siju Limestone offers an abundance of fossils, particularly nummulites (foraminifera). These fossils are found in the limestone outside as well as inside the cave. Since as a principle we do not remove any rocks, formations, or fossils from caves, no cave fossils were collected. The cave walls are clean-washed rock and the fossils that I observed and photographed in situ were embedded in the limestone bedrock. Because we were making a map of the cave and exploration required bolting and ropes, I only had the time to take several pictures of the fossils in the cave – see photos A1-A2 for examples of what we saw in the upper part of the cave. I believe that these photos show nummulites of various sizes, but I do not know if these might represent different species or the size is dictated by the number and hypertrophy of the protist cells contributing to each colony. Please feel free to correct me, as I am essentially new to fossil identification. So far, these fossils seem ordinary, however deeper in the cave, and at the last point of the exploration, I found an intriguing fossil, which I will present in my next post. Any comments will be much appreciated. Mike
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- Cave fossils
- Dec2012 expedtion
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