There are amazing geological formations in nature, from the Giants Causeway in Ireland to the Castleton Tower in Utah, and the various processes by which such formations have long been of interest to scientists. A team of applied mathematicians from New York University has turned its attention to the so-called “stone forests” common in some regions of China and Madagascar. Like the famous Stone Forest in Yunnan Province, China, these directed rock formations are the result of solids dissolving into liquids in the presence of gravity, producing a natural enrichment flow, according to the NYU team. They have described their findings in a recent paper published in the Proceedings of the National Academy of Sciences.
Co-author Leaf Ristroff told Arsen that his group at NYU’s Applied Maths Lab is interested in studying stone forests (technically a type of cart topography) in some indirect way. They were using simulations and experiments to explore the interesting shapes developed in landscapes due to a number of “shaping” processes, especially erosion and dissolution.
He said, “When we left the candy in the water tank and later came back to find the needle-like spire, we first discovered the spikes formed by the dissolution.” “Grade student, first author Mac Huang also accidentally cut himself off while admiring the figure. This led to the problem, and we were very excited when we realized the connection with the stone pinnacles and the stone forests, which has remained quite mysterious. In their development. We hope that our experiments will tell a simple ‘original story’ behind this underground. “
To test their similarities in the lab, the team combined granulated table sugar, corn syrup, and water into molds to form blocks and single pillars of solified (hard-cracked) candy – an estimate of what soluble rocks typically form karst topographs. The molds for the blocks consisted of arrays of straight metal rods, blocks with holes closer to the “seed”. They placed these candy blocks and piles in a plexiglass tank filled with spoiled water at room temperature – so deep that the dissolved sugars settled to the bottom, away from the items being tested. They captured the dissolution process by taking digital photographs at one minute intervals.
Below you can watch a video of the experiment, in which the dissolving candy morph fills an array of sharp spikes like a bed of nails. This block starts at the inner hole and is completely submerged under water, where it breaks down and becomes a “candy forest” before collapsing.
This also happens in stagnant water. “We found that the melting process itself generates the currents responsible for the spike-shaped carving,” Ristroff said. “Basically, the mineral – or, in our experiments, the lollipop candy that serves as the ‘mock rock rock’, melts and the surrounding liquid becomes heavier and then flows downwards due to gravity. So our mechanism There are no other external requirements. Or environmental circumstances: the recipe only involves dissolving liquids and gravity. “
Restroof Et al. Suggests that a similar system has been working in the formation of stone forests on a long-term basis. Soluble rocks such as limestone, dolomite and gypsum are submerged under water, where minerals slowly merge into the surrounding water. After heavy water the bottom gravity of gravity sinks down and the flow slowly forms a cart topography. When the water recedes, the piles and piles of stones come out.
On the surface, these stone forests look very similar to the “Penitents”: icy pillars of ice that form in very dry air have been found in the Andean glaciers. Some physicists have suggested that when sunlight evaporates ice without passing through the water phase (etiquette). Small crashes and sinks form, and sunlight gets trapped inside them, generating extra heat that creates deeper pits, and those curved surfaces act like lenses, accelerating the enhanced process. The alternative proposal adds an additional mechanism to account for the odd intervals of the Penitents for fixed distances: a combination of vapor diffusion and heat transportation that produces extreme temperature answers, and therefore sub-elevated rates.
Physicists are able to recreate synthetic versions of Penitence in the lab. But penitents and stone forests are really quite different in terms of the mechanisms involved in their formation. “I think the similarities are very superficial,” Ristroff said. “Certainly, the ‘sculpture’ process is very different in terms of driving effects. Primarily, our spikes are very carved by the flow, which to me does not play a major role in the formation of penicillins.”
Granted, NYU researchers achieved their results under ideal conditions – according to the authors, it is better to clearly identify and characterize the sharpening process, the underlying method and the mathematical structure. As a result, “this study reveals a minimal set of components needed for the purposes of needle and bed-nails f-nails,” the authors wrote. In the future, they hope to further test this formation process in the lab under various environmental conditions, such as how it is buried under rain and surface runoff, or loose silt, which could affect the formation of Pinkle.
DOIS: PANS, 2020. 10.1073 / PNS001524117 (DOIS.
