High-altitude Archaeolgy - August 2017

February 16 2017

Our August 2017 expedition plans to conduct an expanded archaeological survey, including a series of dives at extreme elevation, to investigate, map, and document pre-Incan/Incan ruins and artifacts in and around Laguna Sibinacocha located at 16,000 ft in the Peruvian Andes. Our expedition will utilize an OpenROV remotely operated vehicle (ROV) to document ruins and artifacts that we have already discovered in the lake, and to investigate and document new underwater sites, including those too deep for diving at such extreme altitudes. The ROV will also help target new dive sites, conserving the limited diving gas we’ll have at this remote location. An unmanned aerial vehicle (UAV) will be used to facilitate pedestrian surveys and to map the terrestrial findings and the surrounding landscape features.

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February 16 2017


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Name: Preston Sowell
E-Mail: sibinacocha@gmail.com
Account ID: 69101699

Preparation Stage

Here's an example of what we can create using UAV-generated orthophotos. This is a digital elevation model (DEM) of one of the archaeological sites that we've already found. It was done by our UAV wizard, Larkin Carey of Falkor Aerials using a DJI Phantom and DroneDeploy's software. We're hoping to produce DEM's for every one of the structures we find so that our archaeological team can more easily study them when we're out of the field. This tool also saves valuable time when we are working in such a large area and at elevations that make it difficult to cover ground quickly. Larkin reports that the altitude does make flying a bit more difficult and it really chews through batteries!

Also included is a still image from the same scene for comparison.

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Interesting. Are you using photogrammetry for the 3D models?

That's correct David. We program a flight path to collect sufficient photos (including enough oblique photos) so that an accurate 3D model can be generated using photogrammetry. The DEMs can then be collected from the same dataset. I'm finding that details jump out in the DEMs that are not as obvious in the still images or 3D models (and visa versa). If I can edit the post, I'll include a still image for comparison. Now, I'm looking into applying a similar technique underwater using an ROV, which I understand is a bit trickier.

Expedition Background

Lying at 5000m/16,000ft in the Cordillera Vilcanota range of southern Peru, Laguna Sibinacocha is the largest (2.4 x 18km/1.5x11mi) high-alpine lake in South America. In 2011, expedition leader Preston Sowell discovered submerged ruins in the lake and the finding corroborates local legends that tell of structures submerged there. A dam was constructed at the lake’s outlet in 1992, but the ruins are located below the maximum depth that the dam raised the water level, indicating that the ruin site’s immersion occurred in an earlier time period. Regional paleoclimate studies indicate that prolonged dry periods have caused significant fluctuations in regional lake levels. Notably, one of these droughts occurred between A.D. 1160 and 1500, which is when the structures were likely built on the lake’s historical shoreline.

The highland people viewed mountain lakes as sacred features in the landscape and ceremonial sites were often placed in proximity to significant lakes. It is also intriguing to note that archeologists consider the highland region around Sibinacocha to be a “blank spot on the map” relative to Andean archaeology.

In 2015 and 2016, Sowell mounted two National Geographic-funded archaeological expeditions to the site with a team of Peruvian archaeologists. Those expeditions revealed that one of the submerged structures is a 100m/300ft long structure depicting a snake and made entirely of golden-colored stone, which indicates sacred architecture. Zigzag lines representing a serpent appear repetitively in the region between A.D. 900 and 1532. What appear to be intact offering pots were also discovered on the surrounding lake bed. Based on photographs and a chip sample collected by an underwater archaeologist during the 2015 field season, ceramic experts in Peru dated one of the pots to the Late Intermediate Period (A.D. 1000-1470), which correlates to the dry period from A.D. 1160-1500.

Despite the large survey area and the limited time that we had on those expeditions, our team has also documented 21 rock piles known as sayhuas and apachetas, 42 structures (including chullpas/tombs and likely ceremonial structures), and rock shelters. On the 2016 expedition we discovered a complex of five to six structures below a peak located near the shore of the lake. Our archaeologists believe that the complex is the most significant find made at Sibinacocha to date. Ceramic fragments have been collected from the various sites that date from the Middle Horizon (A.D. 100-1000), Inca (A.D. 1470-1532), Colonial (A.D. 1532-1791), and contemporaneous periods. We’ve also collected numerous lithics, including arrowheads from the Archaic period (>1500 B.C.). The relatively high artifact densities were surprising for such a high and remote site, and the archaeological findings, coupled with an evaluation of sacred landscape features, indicate that Sibinacocha held ceremonial significance to pre-Hispanic populations.

As with the high altitude mountaintop, Incan, ceremonial sites, the submerged site presents an extraordinary opportunity to study a sacred, pre-Incan/Incan structure with its offerings intact and as they were originally placed. The discovery of such a site is a novel find, even in Peru. Unfortunately, the lake's rapidly dropping water level and its exceptionally clear waters are making the structures and artifacts more visible and more accessible from shore, which could facilitate looting.

In fact, the lake's entire watershed is currently under threat. As trekkers move through the area with increasing frequency (overflow from popular, nearby treks such as the Inca Trail), the historical structures and artifacts around the lakeshore remain unprotected. A mining concession has been granted on the pass above the north end of the lake, near its primarily water source. Prospecting is already being conducted and miners are frequenting the area. Laboratory analysis of the ore identifies high gold content, which means that the mining is likely to intensify. Alarmingly, the ore was also high in sulfur-bearing minerals (pyrite), which cause an irreversible reaction that creates acid rock drainage when exposed to air and water. This could irreversibly and catastrophically affect the cultural material and the riverine and lake ecology for many years to come.

EXPEDITION OBJECTIVES: The significance of the submerged structures and surrounding offerings lies in their extraordinary state of preservation and lack of physical disturbance. Rapidly changing environmental conditions in the Sibinacocha watershed, coupled with new anthropogenic threats, mean that the site is becoming vulnerable to damage and looting. Therefore, the goal of our 2017 expedition is to conduct a rapid survey of the area to define the extent, function(s), characteristics, construction material, and the amount and types of cultural material in order to facilitate a plan for site stabilization, protection, excavation, and the recovery of cultural material.

Due to the cold water, altitude, and remote location (limited scuba tanks can be carried in on horses), our team will use an OpenROV remotely operated vehicle (ROV) to document ruins and artifacts that we have already discovered in the lake, and to investigate and document new underwater sites, including those too deep for diving at such extreme altitudes. The ROV will also help target and prioritize new dive sites, maximizing the limited diving gas and underwater time that we’ll have at this remote location.

We will utilize a differential global positioning system (GPS) coupled with an unmanned aerial vehicle (UAV) copter with a high definition (HD) camera to capture drone-generated orthophotos, which will allow us to rapidly survey the cultural sites and their surrounding landscape features. This will allow us to generate maps and a 3D model of each location, which will help us better understand if/how the sites may be related to each other and to significant local and regional landscape features (i.e., their integration into the landscape). Under recent Peruvian law, landscapes designated as “Cultural Landscapes” (those modified and utilized for important cultural purposes), are afforded protection. Additionally, cosmological alignments were important to pre-Hispanic, Andean cultures and the 3D model will allow us to evaluate potential cosmological alignments between the structures and landscape features. We have already recognized important alignments at several of the sites.

Following the expedition, we will produce a written report for submittal to the Peruvian Ministry of Culture (MOC) to promote official cultural site recognition and associated protections.

This project is being conducted in conjunction with the Peruvian Center for Maritime and Underwater Archaeology/El Centro Peruano de Arqueología Marítima y Subacuática (CPAMS) and our expedition will mobilize in August 2017.

For more about the ecological and climate research being conducted in the area, please check out our non-profit's website: www.sibinacocha.org.

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Hello all! I'd love to hear your thoughts on creating 3D model using OpenROV products.