Soil In American Samoa

In American Samoa, digging a pit is no simple task to undertake, particularly for a group of students with nothing but a shovel. The soil here is hard and compact, full of pebbles and lava rocks. Attempting to dig a pit would have been toilsome and ultimately fruitless. Fortunately, while on a fieldtrip, my classmates and I came upon an archaeological dig site. It was basically a big pit, about five feet deep, that was perfect for our observations. There were obvious changes in the soil through the different levels, and the archaeologist on location provided specific scientific information on the contents and properties of each level. There were five levels of soil in all, arranged in descending order. Level one contained the type of soil
that is common here in American Samoa. It is a deep brown, and even darker than usual because of the moisture that had absorbed into it. This soil is classified as silt clay; it is very fine and is thus soft and smooth. Recent rainwater had soaked into the soil, making the particles in the soil cling to each other in clumps. The soil is extremely rocky with many pebble sized water rocks, which are called ma’avai in Samoan. These are smooth and dark grayish-brown, and the moisture makes them appear slimy. In the second level, the soil is composed of silt loam, which is a very moist type of soil that is fine and soft, but sticky and clumpy when wet, which is the case while we are observing it. The coloring of the soil is medium to dark brown—lighter than the silt clay, though not as light as the sand loam. The soil in this layer is very loosely compacted but only a few water rocks are present. Layer three consists of medium brown sand loam. This is not as finely textured, and is slightly grainier than the soil in the previous two layers. Protruding from the soil are small, white pieces of dead, broken coral. These are the only rocks present in this layer, save for a few large pebbles that seem to be dividing layer three from layer four.
Layers two and three both had some small ferns and grassy plants growing out of the wall of the pit, although none of the other layers did. Since their commonality is loam, I am assuming that loam must be a very rich soil that is useful for growing plants, and is probably very nutrient. The fourth layer is purely made of sand. Sand is very coarse and medium grainy, and the color is predominantly tan or light brown, although there are some darker particles filtered throughout, as is characteristic of sand. The fifth layer also consists of predominantly sand, though of a different classification, which is evidenced by its lighter color. Layer five contains scattered pieces of pebble sized coral, which the prior level had lacked. When my classmates and I had initially decided to dig a pit, we were mildly interested to observe the results. Unfortunately, we did not have the tools or abilities needed to accomplish such a task. We were fortunate enough to come across a ready-made pit, which we could easily observe. The archaeologist helped us to fully understand what we were seeing, so that we could put names to our observations. After completing the observations, I was surprised at how interesting and variant the layers of soil actually were.