Thursday afternoon one of our options was to go for an inland hike. Some of our friends stayed at the research center and volunteered making improvements to the GRC gardens. According to my watch, the hike was just over 2 miles. We had the opportunity to walk over many spiky karst formations. Karst is formed when carbonate rocks are weathered and dissolved by water. Some of the karst rocks were called “moon rocks." We had a portable speaker and were listening to music while we walked across the rocks. We also found some red clay soils and paleosols. These red dust particles originated in Northern Africa and were blown by wind across the Atlantic Ocean. Iron is what gives the dust its red color and can be found in the pink rocks and paleosols. In her history lecture, Mrs. Gerace said that the indigenous Lucayans used the clay deposited to make pottery.
The island of San Salvador has many hypersaline lakes, some of which were once connected to the ocean. The water parameter we focused on during our hike was salinity. Many of the lakes had a salinity close to ocean water because they are still connected to the ocean underground! During our hike we got to see airplanes landing and the lighthouse we visited yesterday. One awesome thing we saw were shell fossils! We walked over an area that was previously an underwater grass bed. It is a part of the Cockburn Town member like the coral fossil reef is, so it was formed during the Pleistocene. While we were walking, we saw cotton, cacti, succulents, orchids, and air plants. We were also actively trying to avoid the prickly plants. There were lots of lizards too! Near the end of the hike, with our water bottles close to empty, we walked over a concrete slope that was constructed to collect rainfall as the main source of the GRC’s drinking water supply. The sandy soils and karst rocks of the islands would allow for high rates of infiltration, but because the concrete is an impermeable surface, the rainfall flows down the slope to the collection grate. The collection system was originally built by the Navy when they built the station. At the end of our hike we saw iguanas hiding between the station's water supply system. Overall, it was a great afternoon and we got to see a variety of cool stuff!
This post was contributed by Katherine I.
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