I have read numerous versions of how modern civilization might appear in the future archaeological record. However, I liked this particular exploration of what Shanghai Tower, a 2,000 foot structure, might become over millions of years.
Almost immediately, water making its way down to the lowest levels it will react with the calcareous material in concrete, to form cathelmites – stalactite- and stalagmite-like growths that form in human-made environments. These will continue to grow for thousands of years, transforming the shopping mall into something akin to a horror movie set. If humanity is still around, most things of value will have been stripped out before the Tower is completely abandoned, but perhaps not everything. Aluminium in the ventilation system, stainless steel in the food court – maybe even a few cars in the garage levels will be left to perform remarkable transformations…
The story continues even deeper underground. The entire Shanghai Tower sits on top of a concrete raft, one metre thick and covering nearly 9,000 sq m (97,000 sq ft). Beneath this are 955 concrete-and-steel piles, each a metre in diameter, driven up to 86m (282ft) deep into soft ground. After several million years, as the weight of the sea water and sediment warps the subterranean layers beyond recognition, some of the foundation piles will fracture, twisting within compacting mudrock formations like the fossil roots of an immense, long-vanished tree.
As millions of years stretch into tens of millions, the transformations come more slowly. Rare earth minerals, leached from discarded mobile phones and other electronic devices, may begin to form secondary mineral crystals. Glass from windshields and shop windows will devitrify, darkening just as obsidian does after long burial. By now, the entire city is compressed to a layer perhaps only a few metres thick in the strata. All that is left of Shanghai Tower is a geological anomaly studded with the fossil outlines of chopsticks, chairs, sim cards, and hair clips.
All of this will be deeply buried, in some cases thousands of metres down. But geology never stands still. After around one hundred million years, as new mountain ranges begin to form, the layer of compacted rubble that was once Shanghai Tower may be pushed upwards, and revealed.
A tower is not just a modern landfill or a single-family home; it is a monument to modern society in a similar way to the massive temples of past civilizations.
The idea that the tower would emerge again as part of a new mountain range is an interesting one. The assumption in a lot of these modern fossil/future archeology writings is that modern civilization will mostly disappear from the Earth’s surface. Many science fiction writings have the same idea: all that modern humans prize in the Industrial Revolution and urbanization will fade away just as everything else has in the past. Certainly, modern structures and infrastructure will only last for so long. What exactly is the predicted lifespan of a major skyscraper, let alone a single-family home or a big box store? Or, all of it will go away due to disaster, war, or the accumulation of garbage and self-induced environmental catastrophe.
Given how we dig and reconstruct the past, I still find it interesting to ponder that someone might come along and dig down and discover a major city that looks abandoned. What was life like there? Why did the city disappear? This was a global city?