Sampling Cerros' Demise: A Radiometric Check on the Elusive Protoclassic

Interpreting the Construction Sequence

CCADP excavations, in tandem with the new dates, provide some added detail to the sequencing of monumental construction first proposed by Freidel (1986) and modified by Reese (1996). Based on current information most buildings can now be tied directly or indirectly to an absolute chronology (Figure 12). One highlight is the relatively late date on public Str. 2A-Sub 4-1st located in the nucleated village east of the site core. The date is associated with its interment under plaza 2A. Recalibration significantly impacted this date, moving it from 57±40 BCE to a y-intercept of 10 BCE. The tight 1-Sigma range (50 BCE - 40 CE) overlaps with other building construction elsewhere in the monumental center. Freidel was not able to determine conclusively whether Plaza 2A buried the entire village before construction commenced in the monumental core. The revised cluster of dates suggest that at least part of the village was open and in use while monumental construction was underway in other parts of the site.

Excavations and dates obtained from Str. 5E significantly impact the overall site chronology as well. Tests in the vicinity of Plaza 5A anchored Freidel's original construction sequence. CCADP investigations revealed the surface of Str. 5E-Sub 1, which probably constituted part of a triadic group with 5C-2nd and 5B (unexcavated). A sample of this substantial charcoal lens, an early termination deposit, yielded a y-intercept of 50 BCE. While it provides a much clearer association for dating 5C-2nd, ironically it closely aligns with the prior interpretation of the 2A-Sub 4-1st date at 57 BCE. It should also be noted that if in fact 5E is part of a triadic group, the termination rite on 5E-Sub 1 may date the burial of the 5C-2nd façades.

A date was obtained on the exterior of Str. 5E from a trench cut into the east wall of Str. 5E (Mitchum and Reese-Taylor 1995). Excavation determined the building to be apsidal in shape with apron molding (Figure 13). Excavators contacted a termination deposit lying atop Plaza 5A, Floor 1, from which the sample was collected (Beta-188412). With a y-intercept of AD 60 and short 1-Sigma range of 20 - 85 CE, this probably dates the end of the building's Late Tulix use. It is virtually identical to the date of a similar context atop Str. 29.

Structure 29 is located about 300 meters south of the site core in the dispersed settlement (Figure 14). It was reported by Freidel (1986). The large pyramidal building supported an oddly configured triadic set of superstructures with only narrow alley-like passages between them. The buildings exhibited polychrome façades described by Freidel and Reese (1996). The termination deposit yielding a carbon date was located along these alleys. Freidel (1986:12) reported the date as 25 BCE±50 for this building termination (SMU-906). Recalibration produced a y-intercept of 50 CE and 1-Sigma range of 30 BCE - 100 CE, considerably later than previously thought. This later date better fits the sequence of construction, use and destruction at the monumental core, linking Str. 29 to a single, unified site-wide building program.

The only date produced from Str. 6A/E was slightly earlier than expected, with a y-intercept of 5 CE and 1-Sigma range 45 BCE - 55 CE. The context at the summit of the 6A staircase (Figure 15) was arguably the latest addition to this building group, as the construction of 6E limited access to the summit. The group has a total of 8 superstructures atop it in an Eight-House-of-the-North configuration (Reese 1996). Freidel has argued that Str. 6 was constructed earlier than Str. 4.  This cannot be confirmed by the present research, although it is apparent that Str. 4 saw later modification than Str. 6.  In fact, the building sequence at Str. 6 seems collapsed into even fewer generations than originally anticipated. Apart from tentative evidence for and earlier Str. 6A-Sub 1, it now appears that work began at Str. 6 sometime after 50 BCE and all modification ended within 50 or 60 years. Reese (1996) identified the banner stone which now lies at the base of Str. 6 (Figure 16). She has suggested it may have been pushed off the top of the staircase in a war event. If the 6A/E modification dated by this sample was constructed after the monolith was pushed down, then this date would serve as a terminus ante quem for the war event.

Three of the six Beta dates were drawn from deposits atop Str. 4A, at its juncture with superstructure 4B.  The two late dates detailed above stem from unsealed termination debris. The third, Beta-188411 was collected from a sealed construction sequence. The original summit of 4A (Floor 3) had one major renovation (Floor 2) and one minor replastering (Floor 1). Termination deposits were encountered atop Floor 1, and the puddled mound of façade melt lay atop Floor 1, preserving it quite well in places. A test into Floor 1 in this area produced the charcoal sample between Floor 2 and Floor 3, dating the first major modification of the original summit (Figure 17). With a y-intercept at 55 CE and 1-Sigma range of 5-80 CE, this is the latest securely dated construction context at Cerros.

The summit of 4B is comprised of a semi-subterranean vaulted building (Figure 18; Chamber 1) investigated by Freidel (1986) and discussed by Walker (1990) and Reese (1996). Hubul ceramics found below its collapsed vault were likely deposited well after its original intended use, although probably not as late as proposed by Walker (1998). Original construction of the chamber may be tentatively linked, as a terminus post quem, to the major modification of the 4A summit ca. 55 CE, making Chamber 1 the latest construction in the monumental sequence. As its cut-block style (Figure 19) differs from other Cerros buildings, and it appears to have had an intact vault at one time, a late date fits well.

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