Natural Science in Archaeology

248 11 Building, Monumental, and Statuary Materials
furniture were made of clay earth by 6800 BCE. Stone construction was a necessity
in more northern regions, where timber was scarce and mud-brick walls would not
survive. With the exception of timber, most building materials reflect the exploitation
of stone resources. An interesting sideline on building stone was reported
recently by Stone et al. (1998). In ancient Mesopotamia, building stone was rare
indeed. The local craftsmen were able to manufacture a gray-black vesicular “rock”
superficially resembling basalt by melting and slowly cooling local alluvial silts.
Another interesting example of “artificial stone” can be seen from the Celtic vitrified
forts of western Europe (Fredricksson et al. 1983). The Celts built fortifications
of timber-laced, stone-filled walls. Some of these were burned, partly causing
the vitrification. A wide variety of igneous, sedimentary, and metamorphic rocks
were involved. The volume of the masses welded together by vitrification reached
several cubic meters.
The people of ancient Egypt, Greece, and Rome were responsible for great
advances in the use of quarried and dressed stone for building. By 5000 BCE, the
Egyptians had learned to shape their comparatively soft Tertiary limestones into
rectangular blocks. The great pyramids at Giza were constructed of limestone blocks
weighing up to 16 tons that were quarried along the Nile River. Harrell (1992) has
found that these ancient Egyptian limestone quarries in the Nile Valley occur in six
geologic formations of Tertiary age. His investigations reveal at least 48 quarries
easily recognized in the field, because the quarry walls show evidence of the careful
extraction of rectangular blocks of stone. Harrell’s petrographic and chemical
analyses indicate that the six geologic formations have distinct signatures.
Before 4000 BCE, the Egyptians had learned how to shape the harder granite and
diorite. By the time of the 3rd Dynasty in Egypt there was a marked increase in the
use of stone for buildings (Fig. 11.1). Limestone was the primary building material,
Fig. 11.1 Limestone pyramids, Giza, Egypt