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I am an archaeologist and I specialize in the ancient Maya. Here's how it happens: 1: The vast majority of ancient Maya buildings are built using a "core and veneer" technique. The bulk of the building's volume is earth and stone rubble, faced with a veneer of nicely-shaped limestone blocks that are themselves covered by a layer of lime plaster (stucco). ...


42

If we consider only the magnetic field generated by natural sources, and not the ones generated by human activities. The general trend is that higher intensities of the magnetic field happen close to the magnetic poles. However, this is just a general trend. The southern hemisphere experiences the highest magnetic fields intensities, reaching over 65,000 nT, ...


16

The accumulation of soil in such situations takes a long time. The main way soil would have been naturally transported there would be by the wind. The wind blown soil would get caught and accumulate. Plants, particularly grasses, would grow on the soil and the plant roots would create mesh that would protect the soil from erosion. You are correct in that ...


13

Since it is not specified in the question (and to complement the other answer), the strongest magnetic fields on Earth are not naturally generated, but artificially. The current world record holder seems to be the National High Magnetic Field Laboratory (NHMFL) in Los Alamos, USA, with a magnetic field strength of about 100T (so about two million times ...


10

One needs breathable air, drinkable water, and food to survive. Food as we know it was nonexistent prior to the Ediacaran, which began about 635 million years ago. Life was exceedingly primitive (single celled) prior to that. Breathable air is a more significant challenge. A breathable atmosphere means sufficient oxygen and not too much carbon dioxide. ...


8

Your question has an incorrect assumption built in. Near surface ground water temperatures are not generally colder, but rather reflect the average annual temperature. This will be colder than surface temps in summer, but warmer in winter. There is an an additional effect if your rainfall isn't evenly distributed over the course of the year, as percolating ...


6

The Earth should probably be cooling, at least, that's what the Milankovich cycles and historical variation and recent temperature charts all indicate. See XKCD and related question on XKCD chart, and temperature chart over the last 800,000 years. Source. Now, it should be pointed out that the Milankovich cycles don't line up in perfect synchronicity, ...


6

Radon (more specifically Radon-222) is produced in the decay chain of Uranium-238. Radon-223 is also produced by the decay chain of Uranium-235 and Radon-220 is produced by the decay chain of Thorium-232 but both Radon-223 and Radon-220 have half-lives of less than a minute, so they almost never reach the atmosphere where they can be breathed in because ...


5

Radon, occurs naturally as an intermediate step in the normal radioactive decay chains through which thorium and uranium slowly decay into lead; radon itself is a decay product of radium. Some granite deposits contain small amounts of uranium. As the uranium undergoes natural radioactive decay radon is produced. In areas where granite underlies ...


4

Most of the Mexican pyramids are less steep than their Egyptian counterparts, and have niches and terraces which their Egyptian counterparts don't. An important difference is the climate, which is much damper in Mexico, and shows how the rainforest can reclaim areas where it has been eradicated if the site is then abandoned. Yet another factor is the type of ...


4

You’re right that there were no future natural forcings experiments defined in the CMIP5 protocol. The reason being simply that the modeling groups thought that other experiments were more deserving of their limited computing time. Compare this with the much stronger call for the historicalNat and historicalGHG experiments, which were required for ...


3

The temperature would stabilize to a steady temperature when you go down 15 ft or so. The point where it gets significantly warmer is probably much deeper than you want to go. A better system would probably be to bury two separate loops that are 6 or 8 ft deep. One is the heat loop on one side of the house and the second could be the cool loop on the ...


2

Disclaimer: this answer is based on what I remember from school and TV. When a volcano erupts with lava flows, the magma cools and forms an inhospitable, sterile surface. The first life to colonise the rocky surface is lichens. When the lichens start dying, they decay into very thin soil layers. Next comes moss which needs a tiny bit of soil. The roots of ...


1

The Accumulation of organic detritus begins when a structure is abandoned or poorly maintained. Plants that thrive without soil (epiphytes, lithophytes) are often the first generation of plants. As they die, new ones take their place and the first layer of accumulated biomass builds to accommodate more sophisticated plants grow in this medium


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