Dating archaeobotanical treasure troves from Armenia and Peru

The arrival of a new issue of Antiquity is always a welcomed event. The issue that arrived in my mail box this week a particular trove of treasures of an archaeobotanical sort. Not so much for archaeobotanical reports as such (the only such is the study by Willcox and  Strodeur on the details of Jerf el Ahmar), but for tantalizing new information of sites that have exceptional plant assemblages, or that one expects will in the future, like the Han era Pompeii, Sanyanzhuang (blogged below). Two sites, which are well-known for exceptional preservation are the Areni-1 cave complex in Aremenia (Areshian et al in Antiquity), left, and Huaca Prieta mound in coastal peru, below right (Dillehay et al.). 

     Areni made the news a couple of years ago for its early leather footwear, from ca. 3500 BC (Pinhasi et al in PLOSone), but it also has dessicated plant remains of many sorts: emmer and free-threshing wheat and barley, of course, but also lentil, grasspea, grapes, plums, walnuts, almonds and pears. How many of these fruit and nuts represent species that were available wild in the region, were under cultivation or introduced as cultivars still needs to be clarified. The site has produced features indicating on-site wine production, so presumably grapes were cultivated, from at least, from around 4000 BC. 4000 BC is associated with the earliest material reported so far, but the site still has much to yield to excavation, presumably including earlier material. Late samples from the past 2000 years include cotton and textiles.

     Huaca Prieta also boasts exceptional archaeobotanical preservation, and with a long sequence it provides information that suggests the chronology of cultivar introductions in this region. Few plants are likely to be native here and so their introductions point earlier cultivation and domestication elsewhere. This includes Cucurbita sqaush, avocado and lima bean at 7000-5500 BC, and thereafter the appearance of chillis and bottlegourds. Cotton cultivation was established around 4800 BC, and after 4500 BC maize was added to the repertoire. This is some of the best dated and documented early maize in South America, detailed of which were published earlier this year (see previous blog). Peanut, sweet potato and quinoa also come from later levels. Full details are not yet published but some summary can be found in the on-line supplement. This site has also produced coca leaves, indicating the long traditions of chewing this drug plant. Dillehay and colleagues reported the earliest for use of this drug, back to ca. 6000 BC, from elsewhere in northern Peru about a year and half ago, also in Antiquity. Intriguingly this drug plant, plausibly from across the Andes, appeared to already have domestication features at this date.

The rapid spread & differentiation of maize: new Peruvian data

New finds from the N. Peruvian coast report clear evidence for an earlier arrival of maize the region than previously thought (Grobman & al., PNAS), and with wonderful dessicated preservation indicating that they are popcorn varieties, but flourly varieties are also present. That there is a popcorn indicates quite rapid early varietal diversification, and these show already traits of South American rather Mesoamerican varieties. A direct AMS date puts these back to at least 4500 BC, so still a few millennia after perhaps 7000 BC date for the earliest maize in its Mesoamerican place of origin. The macro-remains are augmented by phytolith analyses and strach grains extracted both from the maize cobs and tools. Of methodological interest is the apparent discrepancy between dates on dessicated and dates on carbonized material, with the dessicated stuff being way to young. This may mean the dried stuff may sometime get contaminated with young carbon in some way (whereas the charred stuff has it true carbon fixed nicely by carbonization). Also of note is that maize is apparently not the most common plant find, and was not the dietary staple, although the present PNAS article focuses on the details of maize and we will have to await another forthcoming publication in Antiqiuty for more on the chillis, beans, squash and wild plants. Another discussion of this paper can be found in ScienceDaily news report from a couple of weeks ago.

Tropical rainforest archaeology

Just a short not to highlight the publication of a special issue of Quaternary International (volume 249) on human occupation of tropical rainforests, on the theme of how rainforests are themselves artefacts, or "cultural landscapes", to quote from the editorial by Barton, Denham, Neumann and Arroyo-Kalin the papers show "several commonalities can be elicited that enabled hunter-foragers to permanently inhabit rainforest landscapes in different parts of the world"-- which bears on the adaptiveness of Early Modern Human, which lead to cultural parallelisms. In many cases Tropical forests adaptation lead on to agriculture of the more mobile/shifting sort. The volume includes several papers on the Neotropics, Africa and Island Southeast Asia and New Guinea, as well as one on India and Sri Lanka (Kingwell-Banham and Fuller). I have a lot of pages to read and digest, but I previously highlighted on of the African papers by Hohn and Neumann as an excellent example of integrating multiple archaeobotanical datasets, and I regard it as one of the highlights of African Archaeobotany of the past year. I have also previously noted Huw Barton's comparison of rice and sago on Borneo. No doubt many of the other papers in this issue, which I have yet to read, will also be gems.

Locating American bean domestications

A couple of recent papers of the UC Davis crops sciences group, continue the research tradition of Paul Gepts in providing further refinements in out undrerstanding of Phaeseolus vulgaris domestications, especially in terms of locating these two domestications and identifying closed related wild popualations.

Kwak and Gepts published in Theoretical & Applied Genetics 118 [March 2009] an open access paper on a phylogenetic and population structure analysis on wild and domesticated beans, reinforcing earlier inferences of separate Mesoamerica and SOuth American origins.

Further details on the Mesomaerican wild populations, their relationships and distributions, can be found in another paper by Kwak, Kami and Gepts (2009) The Putative Mesoamerican Domestication Center of Phaseolus vulgaris Is Located in the Lerma-Santiago Basin of Mexico, Crop Science 49: 554-563. This study concludes that Mexican beans did not originate in the Rio Balsas valley favoured for maize origins--and supported by recent archaeobotany work, but elsewhere in Southwest Mexico. This was on the News feeds of the Crop Society of America last week.