User:Maisie Anderson/Mlambalasi Rockshelter

= Mlambalasi Rock Shelter =

Ecological Context
The Mlambalasi Rock Shelter is located in the south-central highlands of the Iringa Region in southern Tanzania, 50 km away from Iringa City. The Iringa Region (a high level plateau) is about 1400 m above sea level. It lies within the Usagaran Belt, which was formed 1.9-2 billion years ago, and is characterized by quartzite and granite metamorphic rocks. Granitic outcrops, rivers, and streams feature prominently on the landscape of this region.

In terms of vegetation, the Iringa Region is classified as miombo woodland (meaning a moist savannah with tall, dense tree coverage, a long dry season, and average rainfall of 75-1000 mm per year). In terms of ecological stability and resource availability, Tanzania's Southern Highlands most probably provided refuge from the environmental stress of nearby regions (such as the East African Rift Valley) during all or some of the most recent glacial.

Background
Excavations in 2006 and 2010 by the Iringa Region Archaeological Project (IRAP) uncovered artifactual deposits from the Later Stone Age (LSA) the Iron Age, and the historic periods, as well as external artifacts from the Middle Stone Age (MSA). Direct dating on Achatina shell and ostrich eggshell beads indicates that the oldest human burials at Mlambalasi (and thus the earliest occupation levels) are from the terminal Pleistocene.

A main rock shelter and two additional chambers comprise the Mlambalasi archaeological site. The main rock shelter is situated on the incline of a large granitic outcrop, and is divided into two connected rooms: Room 1, measuring 12x8 m, and Room 2, measuring 4x4m. Room 1 has a high roof, and entrances on the east and southwest sides. The two openings are divided by a large granite boulder which forms a partial wall. Room 2 has two entrances, a small crawl space connected to Room 1, or a west-facing entrance.

Archaeological History
In 2002, a small-scale test excavation was conducted at Mlambalasi by Paul Msemwa, who currently serves as the Director of the National Museum of Tanzania. Historic, Iron Age, and LSA occupations were identified, and Msemwa also found several Iron Age human remains fragments.

Mlambalasi and another rock shelter, Magubike, were introduced to Willoughby in 2005 by Ms. Joyce Nachilema, the District Cultural Officer for Iringa Rural. In 2006, test excavations on Mlambalasi (HwJf-02) began. The Iringa Region Archaeological Project (IRAP) was unaware of the previous excavation, but their excavations did not overlap with Msemwa's. Willoughby recorded surface artifacts such as Iron Age pottery, iron slag, glass beads, LSA white quartz lithics, and crypto-crystalline MSA artifacts. These excavations provided evidence for a continuous, stratified MSA and LSA record, as well as organic material.

No previous Stone Age site excavations in southern Tanzania had uncovered organic remains (such as bones, plant remains, and shells). These finds prompted a general archaeological survey and collection of surface samples spanning numerous archaeological sites from the Acheulean to present in 2008.

The 2006 excavations by Pamela Willoughby, Katie Bliittner, and Pastory Bushozi involved collecting surface material from both rooms at Mlambalasi and excavating Test pit #1, a 2x1m pit with a depth of 120 cm below surface, in the center of Room 1. Test Pit #1 yielded a historic/Iron Age deposit on top of an LSA sequence (which included Burial 1, bisected by the test pit).

Excavations were also carried out by IRAP members in 2010. The primary focus of the 2010 excavations was the recovery of the rest of the human burial and the determination of the relative locations of the excavation units from 2002 and 2006. The rest of Burial 1 was recovered, and the previous excavation units were located and mapped successfully, and LSA and Iron Age materials were also discovered. A German rifle casing that was manufactured in 1877 was found as well.

Tools
Over time in the Iringa Region LSA, technological continuity has been noted, though the size of blanks and finished tools decreased over time, as did the diversity of rock types used. At Mlambalasi, within the rockshelter, a microlithic LSA is stratified above a macrolithic one. MSA lithics were found in disturbed deposits outside the rockshelter on the surface of the slope. The microlithic assemblage is dated to the Holocene, and the macrolithic level is dated to the Late Pleistocene. The macrolithic LSA is characterized by much larger retouched tools and a lower percentage of geometric microliths than the microlithic one. Raw material usage was essentially the same between excavation layers, and raw material and tool type are not related.

More specifically, the LSA lithics include geometric pieces that are 5 cm or less, most commonly made from white quartzite. The LSA lithic assemblages are characterized by low to moderate quality quartzite and quartz (including crystalline quartz). The top LSA layer at Mlambalasi is a microlithic quartz assemblage, with high rates of backed pieces made form bipolar blanks. 93% of the 44,939 artifacts analyzed were quartz, quartzite, or rock crystal, with local outcrops for each material available locally. Less frequently used were chert, granite, and metamorphic rock.

4% of the lithic assemblage was formal tools (backed pieces, scrapers, bi-facially modified pieces, burins, and points). 68% of tools were backed pieces (from 0-10cm below surface), and the proportion of this tool type increased through time (starting at 21% 80-90 cm below surface), while the proportion of scrapers decreased from 32-16% over time. Cores, debitage, and a few nonflaked stones were excavated as well. The bipolar flaking method was most prominent across tools, and the lack of remaining cortex on cores (about 25%) suggests, along with a high proportion of debitage (either complete flakes/blades or angular fragments), that the occupants of Mlambalasi were manufacturing tools and reducing cores in large quantities.

Beads & Ceramics
127 beads have been recovered from Mlambalasi, most of which were recovered in 2010 (besides one in 2002, and 2 in 2006). 72 are ostrich egg shell, 52 are either glass or plastic, and 3 are made from unidentified organic material. Potsherds from Mlambalasi are coarse, porous, have thick and uneven cross sections, and have evidence of partial oxidation or burning. The original vessels were most likely formed by pinching or drawing, and then fired in a hearth. Among all six excavated units, 45.8% are from Iron Age / historic deposits on the surface and within the first 10cm below surface. After 40cm below surface, the presence of potsherds drops dramatically. 58.1% of sherds are smaller than 2.5 x 2.5 cm, 40.7% are smaller than 7 x 7 cm, and most sherds are from the body of vessels. In terms of color, the sherds fall between black and dark red/gray. 98% of sherds are tempered with fine-medium sand. 16.4% of sherds are decorated, mostly with coarse brush strokes or striations. Some sherds have rouletting and two rim sherds have perforated holes.

Rock Art
The interior of the rock shelter, as well as multiple close-by outcrops, contain undated anthropomorphic art in red pigment.

Non-Human Faunal Remains
Highly fragmented non-human faunal remains were discovered. 2006 excavations or recent occupation levels recovered predominantly bovid and caprine remains. Cut marks, calcined bone, burnt bone, and high levels of fragmentation indicate habitual Iron Age usage of Mlambalasi as a campsite.

Human Remains
Two intermixed burials are definitively associated with the LSA: Burial 1 (one middle-aged adult of unknown sex) and Burial 2 (one juvenile). Highly fragmented remains may indicate a second LSA adult (Burial 4). Burial 3 consists of the skeletal material of an Iron Age adult. Flexed burial postures date to 15,000 years ago in Tanzania, and Mlambalasi is the oldest evidence in the Iringa Region. All remains discovered are highly fragmented, with evidence of damage from livestock corralled by local Maasai groups, moving water, insects, and heat damage.

B-1 (extended in supine position, with both arms extended and the skull leaning right, and with legs most likely flexed), is from 70-90cm below surface, near the back of the rockshelter. Despite the absence of a formal burial pit / cairn, cobbles and boulders from the roof covered B-1, and the body was found with three OES beads, dating to the terminal Pleistocene. The head of the body was most likely placed intentionally beneath the overhang of a large roof boulder. It has been determined that the individual from B-1 was either a female or a small male. Many carious lesions are present skeletally, as well as potential pathological changes on the right temple.

B-2 (the second LSA individual found within B-1) remains include a partial juvenile manubrium. A mostly complete, adult upper jaw was also found, with indications of advanced dental disease that may represent a third LSA individual (B-4). B-3 (found near the Iron Age smelting furnace at the entrance of the rockshelter) includes a fragmentary skull, upper arms, and a partial thorax (possibly from a female adult).