In this era of Brexit, Trump and myriad other political upheavals, a deluge of election and ballot analyses can seem inescapable. The news is teeming with pollsters and pundits putting forth models that attempt to factor in all manner of local and national factors to forecast voter behaviour. But are they also taking the local geology into account? Unexpected connections between our modern civilization and the rocks beneath our feet are fascinatingly drawn out by author Lewis Dartnell in his latest book, Origins: How the Earth Made Us.

As curious as it might seem, the Earth itself has, in places, left a lasting mark on politics. In the south-eastern US, for example, a swathe of consistently Democrat-voting counties cuts an arc of blue through the otherwise Republican-red of the political map. The band starts in the Carolinas, runs across Georgia and Alabama, and ends up along the banks of the Mississippi River. Intriguingly, this electoral-college anomaly – which dates back to shortly after the American Civil War – closely follows the exposed geological remains of a 75-million-year-old sea.

The metamorphosed clays that made up the bed of this ancient ocean have ultimately broken down to create the so-called “black belt”– a stripe of dark, nutrient-rich soils that attracted the development of slave-tended cotton plantations in the 19th century. Today, one of its legacies is a concentration in the population of predominantly Democrat-voting African-Americans along the belt. In the UK, a comparable geology-driven voting phenomenon can be observed, with strongholds of support for the Labour Party in the last two general elections matching the locations of buried coal seams underfoot, formed from the repeated burying of plant matter in the mid-Carboniferous-era swamps of around 325 million years ago.

In writing Origins, Dartnell complements the focus of his previous book, The Knowledge – an exploration of how human ingenuity and scientific discovery built the modern world – by undertaking a broader examination of how our world built us. Starting with the tectonic upheaval that drove the evolution of our early hominin ancestors from the apes, Dartnell takes the reader on a seamless journey through time – passing through such milestones as the development of animal domestication and our adoption of baked mud, steel alloy and myriad other construction materials sourced from the Earth – and in doing so lifts the veil of our history to reveal the geology behind the curtain.

Origins’ strength lies in the way it manages to conjure a tight, linear narrative from what would otherwise be an overwhelming wealth of insights, a feat aided by Dartnell’s soothing, conversational writing style. A particular joy comes from the many fascinating titbits that Dartnell uses to punctuate his work, including how democracy owes its development, in part, to the mountainous landscape of Greece, and how there exist small pockets of primordial Earth-like atmosphere in the gut of every cow, populated by anaerobic methane-producing microbes.

Dartnell also invites us to consider an intriguing series of what-ifs that emphasize the tangible impact that geology has had on our world community. For example, if Britain had remained connected by a land-bridge to France, it would doubtless have had a profound impact on both European politics and the British sense of identity – something to ponder in this time of Brexit negotiations. Yet it would only have taken a weaker ice age or a different configuration of the Scandinavian and Scottish ice sheets 425,000 years ago for the conditions that began scouring out the English Channel to have never occurred, leaving intact the strip of buckled rocks (formed when Africa and Europe tectonically collided) that once connected Calais directly to Dover.

It is only in the penultimate chapter – which addresses the impact of the Earth’s circulation on maritime trade and exploration – that the crisp execution of the book’s core geological conceit does perhaps become diluted by historical detail. However, Dartnell fashions such a vivid picture of how sailors learnt to decipher the oceans’ winds and currents in the so-called Age of Discovery, to plot more economical trade routes across the globe, that this change in pace is hardly to the book’s detriment. Overall, Origins is a captivating and enriching read, with as much to recommend it to those with an interest in geophysics as to students of human history and civilization.