According to Science.org, ancient societies all across the world were already utilizing coal’s capacity to manufacture metal or heat water for scalding baths long before it propelled the Industrial Revolution.
A millennium earlier than previously believed, investigations at a Bronze Age site in northwest China have revealed that people were burning coal extensively as early as 3600 years ago. The study, which was published today in Science Advances, also explores the origins of coal and how a lack of other fuel sources may have prompted ancient people to choose coal as their primary source of energy.
History of early coal use has hitherto been “based on who actually writes things down,” according to Shellen Wu, a historian at Lehigh University who was not part in the study. She calls it “very exciting” to be able to utilize archaeology to look back at how humans once used fossil fuels.
People have been intermittently burning coal since the late Paleolithic, or more than 10,000 years ago, according to evidence like pieces of poor-quality coal found in fires. But it wasn’t until the Han era in China, around 2000 years ago, that the first trustworthy written accounts of the widespread usage of coal appear.
Now, that date has been advanced by several millennia as a result of researchers’ excavations at Jirentaigoukou, a sizable Bronze Age settlement in China’s present-day Xinjiang Autonomous Region. The location is close to the Kashi River and is bordered by the massive Tianshan Mountains on three sides. According to Menghan Qiu, an environmental anthropologist at Lanzhou University, this made it a natural gathering spot for the people who settled in the area.
It hosted a robust community between 3600 and 2900 years ago, perhaps made up of immigrants from the Eurasian steppe. These people also brought their cattle, a distinctive pottery style, and knowledge of intricate bronze work to the area.
The village was also covered in coal, ranging in size from tiny cinders to enormous chunks. It was discovered piled high in sizable storage pits and inside buildings. It was also discovered smashed with stone tools and burned in cooking hearths and smelting furnaces. Its adaptability in a variety of situations from daily life suggests that it was probably a “shared resource” that anyone, regardless of class or profession, “could go use for themselves,” according to Guanghui Dong, an environmental anthropologist and co-author from Lanzhou.
Together, the findings reveal that these people weren’t just randomly burning coal. Instead, it seemed that they had created the earliest known mechanism for mass consumption. Environmental archaeologist Jade Guedes from the University of California, San Diego said, “The findings definitely show that coal was used quite frequently at the site.”
The researchers discovered six probable sources for the entire amount of coal within a radius of five kilometers of the settlement. According to Qiu, the exposed coal seams in these locations “crumble off easily” from the cliffs. You can just use your hands to take the bits off or inexpensive metal tools.
The scientists matched the lumps discovered at Jirentaigoukou to three of the sites by using spectrometry techniques to establish the distinctive chemical signatures of the coal from each site. The matched sites had better, more carbon-rich coal than the other three sites, which would have burnt hotter and cleaner.
According to Dong, “I suppose they must have tried burning the coal from all these sites and found some had better quality than others.”
Jirentaigoukou was occupied earlier, between 4600 and 4300 years ago, but no evidence of coal burning was found. Within these early strata, archaeologists only discovered charcoal, which was created from partially burned wood. According to Wu, “people typically use the simplest and closest means of energy available.” Wu continues, “Typically, this entails burning readily available wood and twigs until they deplete nearby forests.”
According to Guedes, the switch to coal may have occurred at a time when Jirentaigoukou residents were considering their alternatives in light of their diminishing timber resources. There may be conflict over whether to chop down the tree, which may be used to build a house, or to find a different fuel source.
Nature might have provided a hint about coal’s potential once people in this region realized the need for other fuel sources, according to Dong. The exposed coal naturally burns and emits white smoke on bright days. He points out that they could have started using this new energy source after connecting the dots at that point.
