A week of rain, survey and coring in Falefa, Samoa

Nick Porch examining a D-section core. Bugs in there will tell us about ancient ecosystems. Photo by Ron Lloren.

Our third week in the field was taken up with a variety of projects: working in the crater lakes to extract paleoenvironmental cores, continuing to map drainage ditches in Falevao and more D-section coring in Falevao. Plus we had several rain days.

We’ve now mapped an impressive network of ditches in Falevao and these mostly seem to connect to the river and likely served to channel water off the plantations during river flooding—we’ll do an elevational and hydrological analysis to test this idea.

Crossing the river to get to a coring site. Photo by Ron Lloren.

PhD student Ron Lloren from the Swiss ETF (Institute of Technology) is here to collect water samples for Hydrogen isotope analysis. The proportion of H isotopes in various water bodies can tell us about periods of aridity over millenia. We’ll correlate these data with our work on the field systems, flora, and insect fauna to generate as complete a picture of changing ecosystems as we can.

Ron takes rain water samples every day to get a baseline Hydrogen isotope signature.

Falefa survey area. The blue feature is a large walled walkway. The red features are single rock walls.

We’re now in our last week or so of fieldwork and back to Falefa mapping landscape features, including massive walled walkways that predate living memory and perhaps represent early divisions of the landscape. Excavations next year will help us determine this.

What one does on Sunday. Photo by Ron Lloren

More on the Land and Agriculture Marsden Project

We’ve recorded mostly walls (yellow) in Falefa near the coast and ditches (pink) in Falevao inland. There are different agricultural strategies depending on local environment.

Our second week of field work had us training another set of NUS Centre for Samoan Studies students, boys this time. We moved inland a bit to survey the lands of Falevao village (some of our Falevao survey area is the banner image), primarily noting and correcting drainage ditches identified in lidar.

We recorded a “fortified site” or at least a set of ridgeline features with platforms, terraces, and “umi ki”. It’s not on any of the Green and Davidson maps, so there’s still some discovery left out there.

Dr Matt Prebble getting ready to face this river section.

We’ve also been facing river sections and taking charcoal and sediment samples. There is a consistent burn layer at about 1.2 m deep across the area with massive charcoal chunks suggesting a big burn of forest. We’ve also found coconut and candlenut endocarp and seeds in the burn layer.

There is a similar burn layer in nearby by Fagaloa Bay that we recorded last year with breadfruit charcoal, and which dates to about 1000 BP.

Taking a break with Dr Brian Alofaituli, student Loto, assistant Pena, and me.

An interesting question for Falefa: why would populations burn off a presumably productive forest? Perhaps (raised-field) taro agriculture became more advantageous? We’ll return to this area in the upcoming weeks for D-section coring and more sampling. Dating should be interesting as well.

Speaking of D-sections: we hiked into a crater yesterday (on maps, Mt. Savaii) to take cores for pollen, micro- and macro-fossils, invertebrates and other goodies to begin reconstructing the paleoenvironment. It was a successful day with an easy 4 m core. We’ll go back to get down to 5 m and do some more collecting.

The D-section extracts sediment in intact 50 cm sections for later analysis.

For the next two weeks we’ll be making more GIS based maps and coring several locations, all to ultimately figure out the processes that explain agricultural and socio-political change in ancient Samoa.