Chiripa Excavations Overview Surface Survey Santiago/Choquehuanca Quispe Alejo Monticulo Llusco Computer Reconstuctions

Choquehuanca -- A Middle Chiripa Semi-Subterranean Structure: Excavations and Interpretations
William T. Whitehead
The structure Choquehuana is an approximately 14 m. by 14 m. square, stone lined, semi-subterranean structure with a prepared plaster floor, cut into underlying sterile soils and adjacent Early and Middle Chiripa deposits. It is located in an agricultural field adjacent to the main Chiripa road, across from the church at Chiripa (figure x). Choquehuanca is now the official designation of this structure to separate it from excavations immediately adjacent to the east which are called Santiago and from the previous interpretation of the structure as a terrace wall. The relation of the structure to the previous Santiago is not currently defined, so designating the structure with a different name helps to reinforce the separation between these two areas and give Choquehuanca a separate interpretive status.
The Choquehuanca excavations in 1998 consisted of two main excavation blocks, one to define the west wall with a shallow trench 17 m long running north to south and another 14 meter trench across the middle of the structure running east to west. 3752 buckets of soil were excavated from these two trenches making the volume approximately 37 square meters of matrix excavated and screened.
The current determination of the age of construction is the Middle Chiripa time period, based on the ceramic analysis of an assemblage recovered from the first construction events and soils in the bottom of the structure (see Steadman this volume). The plan of Choquehuanca (figure x) shows that three of the stone walls have been excavated with only the corners of the four excavated (the south wall). The east wall is the deepest and best preserved section of the structure with the north and west walls almost completely destroyed by erosion of the soil surface and modern agricultural activity. The state of preservation of the structure has however been good enough to describe the structure, measure its dimensions, determine the age range the structure was built in, and when it may have been abandoned. To describe this structure, a brief history of its discovery, excavation, and potential interpretations will be given.
History of Excavations
The discovery of the structure now called Choequehuanca was in the 1992 field season of the Taraco Archaeological Project at Chiripa. At that time the structure was not formally defined but incorporated in the general excavation called Santiago and interpreted as a possible terrace wall, constructed for habitations (1992 Hastorf et al). The 1992 excavations excavated a four meter portion of the east wall, exposing the plastered surface, and giving an adequate enough ceramic assemblage to establish the structure was constructed in or close to the Middle Chiripa time period of the Formative. However, the ceramic assemblage from this first excavation pit was not adequate enough to be conclusive. In addition, due to mixing of several stratigraphic layers at the bottom of the excavation pit, further work was needed to establish the timing of the construction of the structure.
The second excavation of the structure as in the 1996 field season of the T.A.P. These excavations, under the interpretation that the structure was a terrace wall, reopened the 1992 excavation pit. The wall was then followed to the north by removing the plowzone to expose the first course of stones still in situ after deep plowing. An intriguing finding was then uncovered, a square, stone lined pit next to the wall stones. At approximately the same time, excavations to the north uncovered a 90º turn to the west in course of the wall. Half of the square pit, termed the “box” was then excavated exposing the relationship of it to the stone wall, showing the box was indeed part of the general wall and incorporated into it during its construction and not afterwards, as a later time period pit would have been. The excavations of the first exposed corner of the structure continued to the west exposing more of the north wall. Approximately 10 meters of wall was then exposed with intermittent breaks encountered due to its superficial nature and modern agricultural activities. Excavations of the north wall then terminated due to a modern agriculture field boundary and the difficulties in opening a new excavation unit this adjacent field.
The measure from the center of the box to the first corner was almost exactly 7 m., and it was suspected by this time that the terrace wall may be a semi-subterranean structure similar to the Llusco structure uncovered in 1992 and further defined in 1996. A test unit centered 7 m. to the south of the center of the box was placed and excavated. Not far below the plowzone a second corner was found confirming that this was not an “L” shaped terrace but at least a “U” shaped enclosure or a structure similar to Llusco. One more test unit was placed at 10 m. to the west of this southern corner to see if the south wall continued as did the north wall. This test unit did uncover more of the south wall, but the southwest corner lay in the adjacent field. The final wall definition would have to wait until 1998.
The return to Chiripa in 1998 found the field boundary from 1996 now gone, and the Santiago field expanded to the west, creating one large field. Permission was now secured for the entire field and excavations could begin on finishing the wall definition and exploring the rest of the structure. As part of the research design defined in part in the 1996 report to DINAAR, several goals were outlined for further research of the Choquehuanca structure.
A. Establish the existence of a west wall
B. Determine the timing and chronological sequence of events of the construction of the structure
C. Determine if the stones found abutting the wall in the southwest area are of a special structural nature
We now proceed with new information gained from the 1998 excavations, that have given answers to these research questions and shed new light on this structure.

The 1996 excavations
The 1996 excavations will be discussed not in terms of the temporal order of excavations but in terms of the chronological sequence of construction events from earliest event to latest event. T.A.P.’s excavation techniques rely on grouping of smaller excavation loci defined in individual excavation units into larger interpretive elements called events. These events will be used here as the main structuring devise, and with the use of the Harris matrix of events presented by event.
B134-Sterile soil
The sterile underlying the Chiripa occupations has not been geomorphologically defined; however, several field determinations have been made. The sterile soil in this area is extremely rocky, and in some cases seems to be almost entirely rock, with soil wedged in-between the rock matrix. This soil is easily recognized in the field by its rocky nature and lighter orange color, from the anthropogenically modified soils above it. Munsell colors of the sterile place it in the range of 7.5 YR 4/2 (dry) to 10 YR 3/2 (wet). Further information about the sterile soils may come from micromorphological analysis.
B70-Cut into sterile for structure construction
The first construction event is the cut into the sterile soil and adjacent Early and Middle Chiripa occupation areas. This cut has completely obliterated the a section of Early and Middle Chiripa occupations excavated in the Santiago area and posses several important questions: Where was this earlier occupation matrix deposited? How deep was the cut, since the surface of the cut is not visible now due to centuries of erosion and agricultural activities. What did the earlier occupation zone look like before the cut? Obviously these questions cannot be answered now due to the loss of the information. These questions do create a noticeable gap in our ability to reconstruct the original height of the wall, how Formative Chiripaños may have used borrow soils, and what the surface of the area was like when the cut for the structure was created. The profile drawing shows the cut into sterile was not level but was a gentle bowl with the slope increasing more sharply as it approaches the side walls. This could have been for water collection and drainage, however a drainage canal or a slope to a corner has not been found because of the destruction of the corner to the northwest and the superficial nature of the deposits in this corner. However a drainage system would have been needed in a structure of this size, and the cut does give the impression one was planned for from the beginning of the project. The cut for the structure to the east abuts the earlier occupations, in the north is visible close to the wall stones and was not excavated below the plowzone, but to the west the cut into sterile soil is to close to the surface to determine if any earlier occupation soils may have been in this area. Therefore from what we now know from the cut the Early Chiripa and Middle Chiripa occupation area is only known from the Santiago excavations.

B145-Wall Stones
The wall of the structure is constructed of smooth, oblong river cobbles of quartzite. These have been placed in the east wall directly against the cut with little fill behind the wall, but in the west and north wall fill was placed between the stones and wall cut. This would suggest the wall was built little by little with stones fitted into easily workable fill rather than hard packed sterile soils or occupation surfaces. Mortar is present between the stones as a slightly darker soil than the general fill, and at least in the east wall a layer of plaster was placed over wall. This would suggest that the stones of the wall were not intended to be seen, even though the placement and general fit of the stones show a high level of skill and knowledge of stone work and are quite attractive to the modern excavators.
The height of the wall will never be know because the top of the structure is now at the surface. The area of the structure is not level either. The profile of the south wall of an excavation trench through the center of the temple shows an approximately 10 cm per 1 m slope to the west that has destroyed all but the lowest courses of stone to the west. At the present the wall can be said to be approximately 60 cm high at its highest. If the structure had a level wall in all four sides of its roughly square shape, then at lest 40 cm of deposit have been lost to the west, with a more than likely chance that more has been lost.
B142-Fill over sterile after placement of wall stones
A grayish (10YR 4/1 dark gray), clay, very rocky fill was placed over the sterile soil and against the lower courses of stones in the structure. This soil in places had weathered green in contact with the sterile soil and was quite easily distinguished from the lower sterile soil. This fill also contained very large pieces of llama bone, ceramic sherds, and rock, suggesting that after deposition very little had happened to this fill to disturb it or further break down the artifacts found in it. The ceramics in this fill are Middle Chiripa therefore making the earliest known event datable by ceramic analysis Middle Chiripa. The previously suspected Early Chiripa age is now disproved and does fit well into the general knowledge that the deposits this structure cuts into are Early Chiripa. Little more can be said about this event except that it is not uniform across the surface but does extend from the east wall to the west wall.
B141-Floor of structure
The floor of the structure has not preserved well but we do know that it was a yellow plaster surface. This surface is now very thin and only occurrs in patches across the surface. 12 m2 of this floor has been excavated, with extensive sampling of the surface for pollen and archaeobotanical materials. The general thickness of the plaster surface was only a few millimeters, but a lighter grey (2.5YR 7/1 light grey), clay matrix makes up the bulk of the floor. This floor over the rocky, artifact rich fill, is less dense in artifacts and has much fewer stones and is of variable thickness between 10 and 2 cm. across the trench were it was excavated. This fill was more compact and had a much different feel than the fill above, with the fill above “popping off” the surface making it easy to define the floor versus the fill able. Analysis of the ceramics presented in this volume show it is also of a Middle Chiripa age.
B10-Fill above floor, post abandonment fill
The bulk of the excavations were to remove the fill above the floor across the 14 meter center trench. This fill was moderately compacted and of a gray brown color (2.5YR 5/2 gray brown). The fill shows no internal structure however in the areas close to the east wall, stones that are of the same general size and shape as the wall stones are abundant. This suggests that as the structure was being filled either the wall was collapsing into the fill or the toss distance of large rock into the pit was generally not very far. The fill does show one internal feature defined as B147-a clay lens with internal laminations. The fill runs the distance from the plowzone to the surface of the plaster floor and is 1.2 m. thick in the deepest excavation areas. The upper parts of the fill are defined as B2- a mixed, loose fill from plowing. Most of the ceramics from this fill are Late Chiripa? with Tiwananku? also present in low quantities. The superposition of Late Chiripa over Middle Chiripa is expected but does beg several questions: Were there substantial Late Chiripa deposits in the area of Santiago that either eroded into the structure or were placed into it? Were did the fill deposits come from? What was the time frame for the filling of the structure? When was structure finally abandoned? Answers to these questions will more than likely remain unsolved due to the difficulties in establishing a chronological sequence in undifferentiated fill and the loss on any deposits over the fill itself. We can say that the structure was in use in the Middle Chiripa period and that it was filled in during the Late Chiripa time period at the Earliest, or the fill was from Late Chiripa deposits.
B147-Clay lens in structure fill
A lighter clay lens was encountered in units N1092 E961-963 of the central trench above the floor well below the surface. This clay lens was approximately 1 to 10 cm thick with variable amounts of ash and carbonized material embedded in the structure. The lens was thickest in the center and seems to be from a general dumping event that spread and thinned away from the center. This internal clay lens shows that the filling of the structure was in dumping events but any internal structure is now lost. Artifacts in the lens are from the Late Chiripa time period and are part of the general filling events.
B146-Cut for pit with llama offering.
The cut for this pit is marked by a ring of stones in the southwest corner of the structure.
B133-Llama offering
The fill of this pit has the same texture and color as the B10 fill and B2 plowzone it rests in and is mixed with. The offering was almost totally destroyed by plowing and only a single course of stone was recognized as part of the offering. The position of the offering in the corner area of the structure may be a coincidence and it is of recent origin or it could be related to the wall building itself since it is right next to the wall and the wall cut and of ancient origin. However due to its terribly damaged nature little more can be said about this feature.
B2-Mixed fill from plowing events
This is the plowzone fill, it is of varying thickness and compaction due to tracker plowing. This soil is considered to be a mix of anything below it and any events around it. This soil was screened and artifacts collected however will not be used in analysis or interpretation.
B140-Fill from B10 moved by plow over surface
This event is similar to B2 however it denotes that soils have been shifted over the site by tracker plowing.
B131-Pit cut for Rasgo 209-Historic stone cache
The cut for this pit is not visible in the general fill but is inferred by the lack of large stone from the surrounding matrix. The inability to see a pit cut in the side wall profile shows that this area has either been extremely bioturbated or the pit was immediately filled in with the same soil from the pit excavation.
B132-Pit fill for Rasgo 209-Historic stone cache
The fill for this pit is the same color and texture as the B10 surrounding matrix except where it forms fine laminations in the air pockets produced by the placement of the stones in the pit. The pit is in units N1069 E959-961. The pit is approximately 1 meter in diameter and of unknown original depth due to the lack of a clear pit cut and the plowzone. The stones in this pit are of a large size for the general fill and are either batone fragments or large stone from the construction of the temple. The presence of a pit fill with stones is not uncommon, and this pit was made in the historic period to clear the field of these large stones. A historic ceramic fragment was found in the bottom of the pit fill underneath the large stones and batone fragments dating this pit to the historic time period.
B149-Pit cut for Tiwanaku cut stone cache
The cut for this pit is defined by the difference in color and texture from the pit fill and the sterile soil it was cut into. The pit cut was irregular in shape but is approximately square, with one larger corner.
B148-Pit fill for Tiwanaku cut stone cache
This pit was located by the geomagnetic survey of Dr. Don Johnson, which found a strong, localized anomaly in the excavated area. The anomaly was due to the presence of three anedesite, cut stones which look to be of Tiwanaku origin. Anedsite is a magnetically oriented rock because it forms from heated and cool metamorphic rocks and the iron content solidifies in the magnetic orientation of the Earth’s magnetic field. This makes it stand out almost as well as iron in the geomagnetic survey. This hot spot was also interesting because the
B1-Surface
The surface of the Choquehuanca area. This was surface collected and all artifacts taken in a collection, however will probably not be analyzed.

Discussion
The 1998 excavations have touched on or directly addressed the three main issues raised in the 1996 excavations. We have shown that there is a western wall and at least one more intact corner in the southwest. The construction sequence and the timing of the construction have been determined to be from the Middle Chiripa period. Unfortunately, the area in the south wall was damaged by plowing events and the rock structure found in 1996 is no longer visible making interpretation impossible at this time.

Revised September 20, 2002 12:41 - For broken links or comments and suggestions email whitehea@sscl.berkeley.edu.