ASM Occasional Electronic Papers No. 1: Homol'ovi IV

Chapter Two:
Environment

E. Charles Adams

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Geology and Geological Resources

Homol'ovi IV sits on top and along the south and east sides of a 15 m-high butte whose cap rock is erosion-resistant Moenkopi Formation. On Homol'ovi IV and surrounding buttes, the Moenkopi Formation consists of 3-5 m of dense, fine-grained reddish-brown sandstone that is underlain by interbedded layers of silts and clays that are red, green, and yellow (Lange 1998:4). The interbedded layers are exposed on the north and west sides of the butte and are visible in a vandalized room at the base of the cap rock on the southeast side of the butte. Lange (1998:4) notes that some of the clay layers are suitable for pottery and mortar used to cement the rock walls of the village. Such a use could explain a large undercut area on the northeast side of the butte, adjacent to the pueblo's walls, where the clay has been tested and found suitable for clay or mortar. The undercut nature of the beds are identical to clay beds beneath Walpi on First Mesa that the potters dug out for their pottery clays (Stephen 1936). The color and sand-silt-clay ratios of some of the clays match the mortar and plaster recovered from excavated or stabilized walls of the village.

At the base of the butte are cobbles of chert and some quartzite that cap outcrops of Moenkopi Formation throughout the Homol'ovi area. Kolbe (1991) interpreted these as erosional remnants of the Shinarump Conglomerate that still overlies the Moenkopi Formation on the mesa west of Homol'ovi IV and the mesa on which Homol'ovi II is situated, directly east of Homol'ovi IV. The Shinarump Conglomerate is considered by most geologists to be the basal member of the Chinle Formation (Chronic 1983). The Shinarump is variously cemented causing some sections to erode into the cobbles, such as are visible at the base of Homol'ovi IV, whereas other sections form solid caps to mesas. Many of the chert cobbles at Homol'ovi IV have been broken by the inhabitants of Homol'ovi IV and are the primary source of cores for the flaked stone industry at the village. The quartzite members have frequently been battered from their use as pecking stones to shape manos and metates, shape building stone, or peck glyphs into the boulders on the west and southwest side of the butte.

Some members of the Shinarump conglomerate were cemented with opaline silica or quartz and were the primary source of ground stone material for Homol'ovi IV occupants and subsequent generations of Homol'ovi villages, although Moenkopi Formation sandstone having quartz and calcite cement was also used (Fratt and Bian-caniello 1993). A quarry for opaline silica cemented Shinarump Conglomerate used in ground stone manufacture at Homol'ovi I has been identified near Homol'ovi I (Adams 2002). The quartz and calcite cemented varieties could have been obtained from outcrops west of Homol'ovi IV. The Moenkopi Formation sandstone was derived from the Homol'ovi IV or other nearby buttes. The sandstone slabs used as flagstones on Homol'ovi IV and other Homol'ovi village kiva floors and for various bins was obtained from a source southwest of Homol'ovi IV called Five Mountains (Fratt and Biancaniello 1993).

Water Resources

As noted in chapter 1, Homol'ovi IV is located to take advantage of two sources of water: nearby springs at the base of the Moenkopi Formation in the mesa to the west and the Little Colorado River to the east. The Moenkopi Formation underlies the floodplain to about 2 km north of Homol'ovi I causing the river to flow above ground. Beyond this point the river flows underground except during high stream flows, which usually occur in March and April due to snowmelt and in the summer from mid- to late July to mid-September from monsoon rains (Adams 2002; Lange 1998). When the river was dry near Homol'ovi IV, occupants could have accesses water by traveling upstream 4 km of walking to One Drop Spring or other springs to the west. One Drop Spring is 1 km west. According to Mike O'Haco, who has ranched the area since the 1960s, the spring was developed by ranchers in the 1920s or 1930s by building a berm around the spring to hold water for livestock. Any prehistoric development of the spring was destroyed as a result. Whether One Drop Spring or other more distant springs could have met the water needs of the Homol'ovi IV occupants is unknown, but it certainly could have complemented river water. Although it is possible the river flowed as far north as Homol'ovi IV when it was occupied, the absence of fish in the faunal remains, which are abundant at Homol'ovi I (Strand 1998), suggests this was not the case.

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