AKLIS PROJECT PHOTOMICROGRAPHS

In this study, we compare prehistoric sherds of early Saladoid to the late Ostionoid age from the Prosperity, Salt River and Northside sites to those from the Aklis site, all located on western St. Croix, the southernmost of the three United States Virgin Islands (Figure 1)

All of the photomicrographs are taken using a BH-2 Olympus transmitted (and reflected) polarized light microscope. The thin-sections used are standard (30 micron thick) and epoxy-impregnated. Field of view, magnification, and type of observation (i.e., plane polarized vs. cross polarized) will be indicated.

PROSPERITY SITE

P1 and P2

SALT RIVER SITE

190172 , 190204a, 190204b & 191043

NORTHSIDE SITE

NS-21 and NS-56 (completed)

AKLIS SITE

Ten sherds from the Aklis site were examined from arbitrary 10 cm. Based upon the petrographic investigation, it was possible to separate these sherds into four basic temper groups.

Group I is a coarse grained rock fragment dominated sherd. The rock fragments are plagioclase, potassium feldspar and pyroxene. They are commonly black to red-black, suggesting reducing conditions when fired.

Group II is also rock fragment dominated, but contains two different types of rock fragments. In addition to the plagioclase, potassium feldspar and pyroxene fragments, they also have rounded shale fragments. These sedimentary rock fragments are composed mainly of fine to very fine grained quartz and feldspar in a clay matrix. These sherds also are coarse grained and exhibit a darker color, suggesting reducing firing conditions.

Group III is a limestone and rock fragment dominated sherd. Sherds in this group are finer grained, ranging to medium to coarse grain in size, and have a mixture of angular plagioclase, potassium feldspar, pyroxene rock fragments and rounded shale rock fragments. The limestone is probably from the Miocene-age Kingshill Marl, which underlies the Aklis site location. In addition to these carbonate intraclasts, a few mollusk (or gastropod) shell fragments were found. The overall color of these sherds suggests oxidizing conditions for firing.

Group IV is comprised of shell tempered sherds. The shell material is from two different sources. The shell material was either mollusk, and/or gastropod or fossil forams. In addition to the shell material, these sherds also contained some limestone rock fragments and subangular to subrounded quartz grains. The overall grain size is fine to medium and the conditions of firing were oxidizing. The presence of shell allowed a tentative evaluation of firing temperature based upon the aragonite-calcite geothermometer of Garrels and Christ (1965). Calcite decomposes to lime and carbon dioxide above 840.5^oC, aragonite at 813.8^oC, and dolomite decomposes to lime, MgO, and carbon dioxide above 784.2^oC. Since both carbonate phases were found in these sherds, the firing temperature did not exceed more than 800 degrees centigrade.

Aklis Sherd Petrographic photographs (completed)

Level 2 - Aklis 134.13

Level 3 - Aklis 135.17

Level 4 - Aklis 135.13

Level 5 - Aklis 137.29

Level 6 - Aklis 138.29

Level 7 Aklis 139.22

Level 8 - Aklis 140.15

Level 9 - Aklis 141.2

Level 10 Aklis 142.15b

Level 11 Aklis 143.2

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Last revision 30 July 2002