This season while working in the New World Archaeological Foundation lab in San Cristobal de las Casas, Chiapas, I worked on a side project creating 3D models of complete and nearly complete vessels recovered during the 2014 Izapa Household Archaeology Project excavations. The vessel depicted here is half of a miniature jar dating to the Early Classic period (ca. AD 200-400). The model was created using close-range photogrammetry, a process that uses digital photographs taken from different positions to create a 3D model. For more on photogrammetry, see my page on 3D methods.
This model was created by taking pictures with a small point-and-shoot camera (Nikon CoolpixS9500) and was processed using Agisoft’s Photoscan software. To help the program match points (to help overlap the photos taken from different angles) I included “targets” in all of the photos. Targets used here included 2 clothespins of different shapes and sizes and a 10 cm scale bar. Photos were taken around the vessel from 17 different positions. These are marked in Photoscan by the blue rectangles indicating the photo number. With the help of Photoscan, you can make 3D models quickly and at a low cost with simple materials. In addition to having digital models of the vessels for presentation purposes, I hope to use a 3D printer to create replicas of these digital models that can be returned to members of the Izapa community.
The pXRF setup for obsidian sourcing at the New York State Museum
The Izapa Household Archaeology Project is still underway and currently in its analysis stage. Above is a picture of obsidian sourcing using portable X-Ray Fluorescence (pXRF) at the New York State Museum. Obsidian is a volcanic glass that was used by many early Mesoamerican cultures to make tools. Each volcanic source that produces obsidian has its own chemical signature, allowing archaeologists to determine its volcano of origin. Most obsidian from Izapa comes from sources in Guatemala, but some pieces originate as far away as the Sierra de Pachuca source in central Mexico. The goal of the project is to check how well obsidian procurement at Izapa relates to trends in ceramic patterns from the Terminal Formative or “Protoclassic” period (ca. 150 BC- AD 200) to the Early Classic period (ca. AD 200-550), an important period of cultural development in Mesoamerica. During this era, the institution of divine kingship was developing in the Maya area. Meanwhile, many sites experienced an abandonment or decline in population. This analysis will help us to better understand Izapa’s relationship with sites in Chiapas, Guatemala, and central Mexico during this important period of change.
Note: The Izapa Household Archaeology Project obsidian was exported with permission from the Mexican Consejo de Arqueología to conduct these sourcing analyses. It will be returned to Mexico at the close of the Izapa Household Archaeology Project.
Kelly with one of the figurine heads her team found this week
Week 8 was another big one for the Izapa Household Archaeology Project. We expanded excavations this week and now have six pits open at once, and opened five new units on three new mounds. The new units have already yielded some exciting finds, including stone architecture and more complete vessels. This week we also found our first figurine heads, a rarity at Izapa. Everyone is working very hard to keep up with all the cool new finds, but we’re feeling very lucky!
Reconstructing the wall in preparation for photos
Excavations continued as usual this week. We finished up some of our long-open excavation units in preparation for opening up new pits next week. This week’s highlight was a visit from Lizzie Wade, a writer for Science magazine. Lizzie plans to write an article featuring the Izapa Household Archaeology Project within a article on the archaeology of neighborhoods.
Update: Wade’s article was released on May 16, 2014. The article is now free to access and can be found here: http://www.sciencemag.org/content/344/6185/684.full
Me floating soils for botanical remains at the New World Archaeological Foundation, summer 2013
This week we began flotation of soil samples in the lab in the search for macrobotanical remains. We are using a simple bucket flotation technique, using the methodology I developed this past summer using soil samples from the Izapa Regional Settlement Project (director, Robert Rosenswig) excavations at Izapa.
Three TV news crews stopped by this week for updates on the project. We were told an update on the project should air on TV Azteca at 11:15 on Monday, February 17th.
We completed one of our deepest units this week, which closed out at approximately 3 meters in depth, before reaching culturally sterile soils. The unit has great stratigraphy, with visibly distinct occupation levels. Capitalizing on the great stratigraphy of this unit, we took our first column samples for future pollen, starch grain, and phytolith analyses. The goal of these samples is to document how Izapa’s land use and environment may have change throughout the different periods of the site’s occupation. Our column sampling methodology was developed based on the recommendations of Iran Rivera, director of the pollen laboratory at ENAH (Escuela Nacional de Antropología e Historia).
This week’s press: http://elorbe.com/portada/02/06/aparecen-mas-vestigios-en-la-zona-de-izapa.html
Me collecting a column of soil samples for future botanical analyses