When did we start the fire?

Methods

Summary

Experiments: 

1. Several fires will be set in controlled conditions. We will take sediment samples from the fire locations before and after the fires are set.

    a. samples will be taken from the center of the fire location, the edge of the fire, and outside the fire. 

   b. samples will be taken at approximately the same place before and after the fires

   c. a second set of samples will be taken with the first set to be analyzed more thoroughly in the wet lab in the US, if necessary

2. Samples will be mixed with SPT (heavy liquid) and spun in the centrifuge to separate the microscopic particles of interest from the rest of the sediment. 

3. The material at the top of the spun samples will be siphoned off and placed on glass slides for analysis with a digital microscope. 

    a. we will compare the materials recovered from within and without the fire location 

    b. we will compare the materials recovered inside the fire location both before and after the fires have been set

4. We will dry out the samples and keep them in the National Museums of Kenya in case we need to look at them later. 

5. We will take samples from the archaeological site, dated to 1.5 million years ago, and compare the material from the site to the materials recovered from the experiments

   a. we will again double sample to enable further sampling in the US 

Challenges

Power to run the centrifuge and microscope will be an issue. In general, the field conditions under which we will be running the analyses will be difficult; it is very hot during the day there, and power is highly dependent on either solar panels and batteries or generators. 

Pre Analysis Plan

We hope to be able to count and make preliminary identification of the phytolith types (microscopic plant remains made of silica; e.g. grass, wood) and get a basic quantification of microscopic charcoal. We will make the following comparisons:

a. before and after experimental fires: 

   1. type and number of phytoliths

   2. relative amount of charcoal 

   3. ratio of grass to wood phytoliths

   4. counts of fire-affected phytoliths 

b. inside and outside archaeological site

   1. type and number of phytoliths

   2. relative amount of charcoal 

   3. ratio of grass to wood phytoliths

   4. counts of fire-affected phytoliths 

c. map concentrations within and around experimental and archaeological sites; compare before and after concentrations to archaeological site