TITLE: Standardized Protocol for Soil Survey and Archaeological Diagnosis for the DOPAMICS Research Program
AUTHORS: Marc Testé, Kevin Mabobet, Julien Engel, Louise Brousseau

[DESCRIPTION]
We describe the protocol developed as part of the ERC-funded DOPAMICS research program for palm sampling in three forested pre-Columbian sites in French Guiana: MC87 near Régina, the "Grand plateau" in the CNRS Nouragues Research Station, and Mont Galbao near Saül. 

This protocol follows the setting-up of the research transect (see "before start" section). It aims to carry out an extensive soil survey and archaeological diagnosis.
This protocol is made open access under the Creative Commons Attribution License (CC-BY). It details the sampling strategy and steps, and the material needed with the aim to encourage future reuses of this protocol for the same or similar research purposes, and to improve the reproducibility of the research conducted. Reuse of this protocol must credit the authors and mention its DOI and download link. 

 


[BEFORE_START]

 
Make sure the satellite phone and GPS batteries are fully charged.
Gather all necessary materials.

[STEPS]
SECTION: Soil sampling
2. Every 50 meters along the central line (at the position of pickets "Cstart", "C1", "C2", etc.) and at the position of additional pits ("RH" and "AH"),

Collect soil samples every 5 cm in depth, starting from the surface to 120 cm in depth
Put the soil samples in zip-lock plastic bags
With a large tip permanent marker, write down the sample ID on the plasic bag
Record the GPS position of the pit

 

SECTION: Lab analyses
3. Samples from 0 to 60 cm are analyzed in the laboratory. 
The remaining samples (60 - 120 cm)  are stored for further analyses.
SECTION: Soil colorimetry
3.3. With a colorimeter,  measure the colour of each soil sample

⇒ Note the Munsell Color value in your lab book or in an excel spreadsheet
SECTION: Selection of macroscopic charcoals for radiocarbon dating (subcontracted)
3.2. For each site, 
Identify soil layers with an increasing abundance of fragments of ceramics and charcoals in pits from the enclosure and slopes of the ring ditch (e.g. 0-45 cm deep) 
Select 10 charcoals >10mg (ideally between 20 and 100mg) for radiocarbon dating
SECTION: Soil conditioning for physico-chemistry (subcontracted)
3.4. 
 

Weigh 100 - 200 mg of each dry soil sample from 5 to 60 cm deep
Transfer the sub-sample in a plastic bag for soil granulometry and chemistry analysis (pH, C, N, P, K, Mg, Ca, Na, Al)
Write down the sample ID on the plastic bag
SECTION: Abundance of microscopic charcoals (&lt; 2 mm)
3.5. The remaining soil samples are used to extract micro-charcoals. 
The abundance of microcharcoals was evaluated every 100 meters along the central line in soil samples from the surface to 60 cm deep. 

 

For each soil sample,
Measure 2.5 cm3 of soil sample with a graduated cylinder containing a solution of sodium hexametaphosphate (Na6P6O18) at 40g/L
Transfer in a 50 mL Falcon tube and fill the tube with sodium hexametaphosphate (40 g/L) up to 50 mL
Incubate the sample on an orbital shaker at ambiant temperature for 12 hours
Sieve the sample (160 µm)
Transfer the sample in a Petri dish 
Oven dry the sample at 50° during 12 hours
Put the Pietri dish on a grid background composed of 0.25 x 0.25 cm squares
Count the number of microscopic charchaols with a 40X stereo microscope and a manual clicker counter

⇒ Note the Munsell Color value in your lab book or in an excel spreadsheet

The remaining soil samples are stored in the plastic bags for further analyses.


SECTION: Foreword: Sampling Strategy
1. Soils are sampled every 50 meters along the research transect spanning from the ring ditch hill (RH) to an adjacent hill or slope with no or sparse evidence of pre-Columian occupation (i.e. adjacent Hill, AH), according to the position of the pickets (Cx= Cstart, C1, C2, etc.).
→ see "Standardized Protocol for Transect Set-up and Palm Inventory for the DOPAMICS Research Program"

Additional pits are collected in the landscape surrounding the central line on the ring ditch hill (RHx = RH1, RH2, etc.) and, eventually, on the adjacent hill (AHx= AH1, AH2, etc.).

 
 

SECTION: Soil samples preparation and artifact extraction
3.1. Weigh wet soil samples
Dry the soil samples drying oven at 50°C
Sieve the soil (5 mm) to remove stones and roots and to extract archaelogical artefacts (i.e. ceramic shards)
Extract macroscopic charcoals (>2mm) and soot deposits from the sieved fraction by hand
Tranfer artifacts in sampling pots or zip-lock plastic bags
With a large tip permanent marker, write down the soil sample ID on the pot
Weigh dry soil samples

⇒ Note the wet and dry mass of the sample, the soil type (hydromorphic or ferralitic soil), presence/absence of stones, roots and artifacts in your lab book or in an excel spreadsheet