![]() I would really hate for these things to get damaged or destroyed.” “I've been trying to find somebody to try and help with this, and in fact I've gotten zero response,” she says. But she says that she needs more help to protect these footprints from the elements-and to keep them as part of the human story. Liutkus-Pierce says that she is in constant contact with the National Museum of Tanzania, with the hopes of conserving the site and ensuring wider access to Engare Sero's 3-D models. But the backfill contained acacia seeds that took root and grew through some of the prints, forcing researchers to re-excavate the site in the 1990s. In the 1970s, scientists tried protecting the Tanzanian site Laetoli-which contains 3.7-million-year-old footprints of our ancient hominin cousins-by backfilling the site. Preserving footprint sites is notoriously difficult, however, since the sediments are soft and easily disturbed. ![]() They also installed a fence around the footprints to prevent people from walking or driving across the site. Between 20, local officials built a small rock wall around the prints to divert runoff. Some protective measures are now at the site itself. But Liutkus-Pierce and Zimmer want to make sure that the physical site remains intact as long as possible. Smithsonian digitisation experts Adam Metallo and Vincent Rossi, coauthors on the new study, 3-D scanned the site in minute detail in 2010. “If we do nothing, the prints will ultimately disappear over time.” Step-by-Step Conservation?Īlready, there is a digital backup of the site, which is known as Engare Sero. ![]() “We can see that even the deepest and most well-developed prints, like the ones we were looking at, were showing significant change,” says geologist and study leader Brian Zimmer of Appalachian State University. In seven years, some spots on some footprints lost a quarter inch in height. And some parts of a given footprint wear down much faster. And winds often whip across the arid site, dragging grit across the footprints like sandpaper.Īcross the site, a given footprint wears down by a tenth to a sixth of a millimeter each year, according to a new study accepted in Quaternary Science Reviews that puts numbers to the losses based on 3-D scans and photographs. The game is won when all cards have been moved to the foundations.The prints lie in an ephemeral river channel that sometimes fills with rainwater. One can redeal the stock as long as there are possible moves from the stock or from the reserve piles to the foundations. When placing cards from the reserve piles is no longer possible, one can use the stock, deal three cards at a time, and use its top card to make possible moves. Once all possible cards have been placed in the foundations, the next face-down cards remaining in the reserve piles are turned face-up. A card can be moved to a foundation if a card of the same value has already been placed in the foundation above it. To begin, the top cards in each reserve pile are the only cards in play and must be moved to the foundations if possible. Foundation piles are fanned from left to right. The other three foundations are also built by suit, but must begin with cards of the same rank as the first card of the top foundation (the 17th card previously mentioned). Cards with the same suit as this card must be moved to this foundation. A seventeenth card is put in the first (top) of four foundations, which are also arranged vertically to the right of the reserve piles. Game play consists of four, vertically arranged reserve piles of four cards each (one face-up card on top of three face-down cards).
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