History
Chert and Flint nodules were important to the pre-Columbian peoples of Antigua from as early as 3,100 BC. They have been found as far north as the Virgin Islands, and Martinique in the south. It is commonly found in abundance at all pre-Columbian sites on Antigua.
While the native peoples did not make or utilize stone projectile points, backed knives and other tools have been found. Their primary neolithic approach was the reduction of cores for the production of usable flakes and chips.
Geology
Chert is a fine-grained sedimentary rock that may contain small fossils. It varies greatly in color (from white to black), but most often manifests as gray, brown, grayish brown and light green to rusty red; its color is an expression of trace elements present in the rock, and both red and green are most often related to traces of iron (in its oxidized and reduced forms respectively).
Flint (or flintstone) is a hard, sedimentary form of the mineral quartz, categorized as a variety of chert. It occurs chiefly as nodules and masses in sedimentary rocks, such as chalks and limestones. Inside the nodule, flint is usually dark grey, black, green, white, or brown in color, and often has a glassy or waxy appearance. A thin layer on the outside of the nodules is usually different in color, typically white and rough in texture. From a petrological point of view, "flint" refers specifically to the form of chert which occurs in chalk or marly limestone. Similarly, "common chert" (sometimes referred to simply as "chert") occurs in limestone.
Flint Nodules
The exact mode of formation of flint is not fully understood but it is thought that it occurs as a result of chemical changes in compressed sedimentary rock formations, during the process of diagenesis. One hypothesis is that a gelatinous material fills cavities in the sediment, such as holes bored by crustaceans or molluscs and that this becomes silicified. This theory explains the complex shapes of flint nodules that are found. (From Wikipedia)
Flint nodules/cobbles found on Long Island generally have a white cortex or surface patina, and ranges from light brown to gray black internally.
Assignment
The coordinates for this Earthcache put you at Flint Bay, which was an old flint mining area. Search the area for some examples of flint nodules or chert. Send me an e-mail with the following information...
1. Measure some of these flint nodules. How big are they?
2. What color flint nodules do you see?
3. How do you think these flint nodules were formed on this island?
4. Post a picture of flint nodules or chert in your log and post the coordinates where you saw them.