The discovery of ‘dark earth’ in the Amazon Rainforest raises questions about Ancient Indigenous People

Since the start of the early 2000s, Schmidt, Heckenberger and others, have compiled a large amount of data and observations about the Amazon while working with indigenous tribes located around the Upper Xingu River basin (ScienceDaily, 2023). Most notable of these observations was the recording of various patches of ‘dark earth’ that were scattered throughout the area. They found that many of these patches were located in close proximity to villages and habitable areas in the Kuikuro Indigenous Territory. 

Fig 1. Areas of study located in proximity to historic sites and habitable areas. (Science, 2023)

To determine their function, Schmidt and his associates began to observe modern Kuikuro practices of managing the soil. Modern practices by these indigenous peoples entails the creation of “middens,” or waste piles, that are made of waste and food scraps left to decompose. This decomposition creates nutrient rich ‘dark earth’ that can be used in agriculture. Furthermore, it was observed that the farmers of this tribe would spread ashes and organic waste in places where they planned to grow crops, thereby acting as fertilizer and a source of nutrients (Chu, 2023).

Fig 2. Test pit of dark earth at Ngokugu site, where there was the presence of ceramics. (Chu, 2023)

After taking samples of modern dark earth and dark earth from archaeological sites, Schmidt and researchers from MIT measured the chemical compositions of both soil, then compared them. They believe that ancient amazon peoples used similar methods as the Kuikuro people to make fertile land for planting due to both soils being enriched with the same elements and having similar compositions; as well as the patterns in which these dark earth areas were made being similar across both sites, where dark earth areas were placed in a radial pattern concentrated in the center that would extend outwards to form a wheel shape. The creation of these fertile areas represents a significant shift in their society from hunter gatherer bands to segmentary societies, which typically use agriculture to acquire food. This shift in food production typically results in increases in population and the development of more complex culture. While the layout of the dark earth in an almost wheel-like structure may be practical for the environment that they are in, the shape may also be indicative of some cultural or religious expression, though that has yet to be determined.

Fig 3. Kuikuro II village in the Território Indígena do Xingu. (Chu, 2023)

While the creation of dark earth might seem underwhelming, it represents a major innovation and significant cultural and social change among the ancient inhabitants of the Amazon. Recognizing that the natural soil of the Amazon rainforest is severely depleted of resources and is unsuitable for growing crops, they developed techniques to insert nutrients into the environment. Rather than forcing the environment to adapt to their needs and changing society, they developed methods to better the environment so that they might thrive there.

Their methods, although unintentionally, created a vast carbon sink and a potential carbon reservoir in the soil (Science, 2023). Perhaps modern society can take this as a learning opportunity and possible method for solving, or at least mitigating, humanity’s impact on Earth’s climate and global ecosystem.


Massachusetts Institute of Technology. “Ancient Amazonians intentionally created fertile ‘dark earth’.” ScienceDaily.

“Intentional Creation of Carbon-Rich Dark Earth Soils in the Amazon.” Science, 2023.

Chu, Jennifer. “Ancient Amazonians Intentionally Created Fertile ‘Dark Earth.’” MIT News | Massachusetts Institute of Technology. Accessed September 24, 2023.

Further Readings:

Smithsonian Institution. “Indigenous Peoples Were Stewards of the Western Amazon.” Smithsonian Institution, January 1, 1970.

Schwartzman, Stephan, André Villas Boas, Katia Yukari Ono, Marisa Gesteira Fonseca, Juan Doblas, Barbara Zimmerman, Paulo Junqueira, et al. “The Natural and Social History of the Indigenous Lands and Protected Areas Corridor of the Xingu River Basin.” Philosophical transactions of the Royal Society of London. Series B, Biological sciences, April 22, 2013.

Cultural Ecology and the Anthropocene

“Cultural Ecology” is the anthropological study of how a group of humans adapted and how societies developed in the context of their environment; weather patterns, climate, native flora and fauna, available materials, and so on. “Environment” is divisible into three categories; abiotic, biotic, and cultural. The abiotic environment of a society includes land, water, minerals, and climate, while the biotic environment is the living things within the environment, such as plants and animals. The cultural environment focuses on the interactions of human beings and the development of societies. Cultural ecology is capable of examining both the effect of environment on a human society, and the effect of human society on its environment.


A woman in the Caribbean tending the fields.

A woman in the Caribbean tending the fields.

Haiti now has only 2% forest cover.

Haiti now has only 2% forest cover.

Archaeological techniques allow us to infer what life in a society is or might have been; in the context of an environment one might infer how a society affected its environment, or why a certain society adapted in a specific way. Though this is largely used to study societies, it can also allow researchers to see how an environment, itself, has changed. For example, the changes in Haitian culture and environment. We may discern that Haiti was once lush and forested, and assume that the natives adapted accordingly. However, after the colonization of Haiti by the Europeans, the forests were razed to clear land for sugar plantations, and slaves from many African nations were brought to work the fields. Today, Haitian culture is comprised of the various cultural traditions brought by slaves from many different nations. As for the environment of Haiti, Haiti now has only 2% forest cover, and has lost virtually all of its topsoil, making it impossible to grow food, and causing widespread drought. As such, a staple of Haitian culture has become its dependence on imports for 93% of its food, and Haiti’s resultant poverty.

The changes of environment as a result of human interaction is the distinguishing attribute of the Anthropocene Era, a geological era in which humans have become so great a geological force as to cause changes in the natural environment on a global scale. Cultural ecology, in its study of human environments, gives us insight into what environments may have been like in the past, as in the case of the once-verdant Haiti. This enables members of many disciplines, archaeological and ecological, to study how an environment has changed, and determine how human action may have led to such changes. It also allows us insight into a society’s reaction to the changing environment—did they flee, adapt, or die out? Did they recognize the change as the result of human activity? Did they attempt to fix the changes? Cultural ecology can be used to study both the changes in an environment, and the societal reactions, allowing archaeologists and ecologists alike to study the development of the Anthropocene as a human-powered geologic era.

More Reading:



Cambata, Altaire. “The Global Impact of Climate Change .” Ecology, n.d. Web. <>.

Standish, Alex. “The Anthropocene: A Man-made Epoch.” Spiked.

Haiti Friends.

Gunn, Michael C. “Cultural Ecology: A Brief Overview.” University of Nebraska- Lincoln.

The Creation and Discovery of Skara Brae – The Power of Storms

The now-archaeological-site, once-village of Skara Brae on the coast of the Orkney Islands of Scotland was subjected to huge storm during the late Neolithic period – burying its structures deep under a layer of sand, which acted as a preservative for the buildings and their contents for multiple millennia – four to be exact. The protective quality of the sand kept the structures and everything within them shockingly intact since around 3200 – 2200 BC. The very gradual drift of sand after the storm embedded the village of Skara Brae into the earth, making it uninhabitable for the original Stone Age villagers.

So, was it the storm alone that drove away the native inhabitants of Skara Brae? Not exactly. “The fall” of Skara Brae as a society and abandonment of it as a geographical location was actually due to long term erosion along the coast and changes in the society’s needs, not only the single event of the storm (though the storm did intensify and speed up erosion) (Orkneyjar). Even before the major storm, island conditions such as the spray of salt water and sand probably made the land virtually unworkable and unfit for food production. While that may have been okay for a while, eventually people moved away to more productive areas where they could get a more constant supply of food. The few who remained most likely finished out their lives in Skara Brae without repopulating the area.

Outside view of a Skara Brae building, separated from others by a passage.

But how was Skara Brae found if it was under a massive layer of sand? Well, another natural disaster occurred 4,000 year later in 1850, a violent storm “whose winds and extremely high tides” ripped up the earth and grass from Skerrabra – a large mound on the island (Orkneyjar). Foundations, walls, and remains of stone buildings and houses were discovered underneath the mound, to the surprise of those living there at the time. But 75 years later, in 1925, another storm came around, damaging the excavated ancient structures. Accordingly, preservation efforts were put in place through the construction of a sea wall (an embankment erected to prevent the sea from encroaching on an area of land), which actually exposed even more stone buildings! During this time period, most archaeologists believed the settlement to be from the Iron Age – around 500 BC. But finally, as we know now thanks to radiocarbon dating in the 1970s, the buildings were proved to be from the late Neolithic period and inhabited for 600 years.

Excavation of a Skara Brae home, complete with artifacts and features such as furniture and drains.

Excavation of a Skara Brae home, complete with artifacts and features such as furniture and drains.

While so far storms seem to have acted in an oddly beneficial way for the archaeological preservation and exposure of Skara Brae’s long-hidden cultural artifacts and features, an increase in erosion rates have posed an environmental and archaeological threat. Steps are being taken to minimize the effects of this accelerated erosion due to natural and human causes.

For Further Reading on Skara Brae:


Renfrew, Colin, and Paul G. Bahn. Archaeology Essentials: Theories, Methods, and Practice. New York, NY: Thames & Hudson, 2010. Print.