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Enigmatic bola date resolved

BY JIM DUNBAR

Of the several dozen carbon dates taken at Page/Ladson only two from Test B are in reverse order (i.e. an older level above a younger level), suggesting a problem for stratigraphic interpretation. Brinnen Carter's lyy5 work on the "Bolen surface" (see "The Bolen Surface") now suggests a solution to the problem of the reversed carbon dates. Bola stones (AKA club-heads) and side-notched Bolen Beveled serrated points were recovered in 1995 near the "Bolen surface The implication that bola stones represented a Bolen-aged artifact (10,000 to 9,500 years old) was an unproved possibility during the 1988 season when a fragment of possible bola from the "Bolen surface" had no diagnostic features for confident identification. Also, in 1985 a bola stone (Figure 1) had been recovered from a level in Test B that dated 12,300 years old, suggesting bolas were much older than Bolen age.

In 1985 a one meter north by 3 meters east-west expansion of Test B uncovered Bolen components embedded in still-water deposited peats followed by a thin, sandy-shell lens below that peat (Figure 2). The still-water peat deposit produced side-notched Bolen Beveled serrated artifacts which carbon dated to 9,730 years old, the deep water equivalent to the "Bolen surface." The sandy-shell lens below the still-water peat produced a Bolen Plain side notched point, but the level was never carbon dated. Below the sandy-shell lens was a level which looked like and carbon dated to the age of the 12,300 year old Limesand straw-mat. How-ever. the Test B limesand did not have the familiar "straw-mat" which rested above and has been found in the Limesand levels of Test A, Test C and Test F.

Test B also lacked the gray silty sediments which separate the "straw-mat" level by more than a meter from the younger Bolen levels. We knew there was an erosional gap in the sedimentary record. The Test B limesand level carbon dated 12,330 + 110 years before present; however a carbon date from a sample more than 2 meters below the Test B limesand dated younger at 12,120 + 120 years before present.

Something was wrong!

Before we go further, just assume we had an archaeological site which developed as sediment "rain" buried two different ages of artifacts at different times in two different levels of sediment in a layer-cake of time. Applying the stratigraphic principle of superposition, younger artifacts should occur in a level above an older level with older artifacts. In Test B we were left with three possible scenarios that might explain the inverted carbon dates which indicated an older level above a younger one:

1). The bola stone was somehow intrusive into the Test B in place Limesand level and represented a younger artifact in an older level. There was no evidence of disturbance in the stratigraphic profile which may have caused contamination. This scenario also demanded that the deepest level, which had carbon dated to a younger 12,120 + 120 years before present, was not correct;

2). The bola stone was recovered from in place undisturbed Limesand sediments and the deeper 12,120 + 120 year old level is not correct, or;

3). The Test B limesand did not reflect the correct age because an erosional event had caused stratigraphic mixing and transport of the older Limesand with younger Bolen-aged sediment into the Test B area. In other words, the deeper 12,120 + 120 year old level reflects a good date, while the older but shallower date reflects the correct age of a redeposited Limesand displaced by an erosional event which took place during a Bolen-age time frame; Because Carter found bola stones in unquestionable Bolen context in 1995, it now appears that option 3 is most likely.

Therefore, the deepest in place level of Test B dates 12,120 + 120 years old and may indicate we never reached undisturbed elements of the Limesand in that area. This implies that the equivalent of the Test F mastodon bone bed will occur at a lower elevation of 10 feet or more in the Test B area.

Following this line of reasoning also suggests the late ice-age Page/Ladson sinkhole was deepest on its southern end and became generally shallower to the north. And, from what we have established in Tests D, D', E, F, and II, the shallow side and entrance into the sink was on the northeast end. There is a decline in the elevation of Paleoindian aged sediments from 15 feet below the present water's surface on the northeastern end of the sink to 30 feet below the present water's surface in the central area of the western bank (the Test F area). Sediment coring conducted by David Kendrick to the north, northwest of Test F suggest it becomes shallower until rock cliffs are encountered.

Among other objectives, it is our intent to move testing from the Test E area towards the north northwest in order to follow the uneroded sections of Paleoindian age sediments into the known bone bed and toward a shallower profile.