Read Coal Black Heart for Free Online

solar energy, and converted it into chemical energy and carbon that stayed stored within their cells until they decayed, burned or got eaten. Usually, when plant material dies, it decomposes more rapidly than it accumulates. Peat, the precursor to coal, forms when the reverse is true—when the wetland has a waterlogged surface with little access to oxygen, and this protects the plant matter from bacteria, fungi and other organisms that cause decomposition.
    Whether or not peat will form depends mostly on climate and geology. Precipitation has to exceed evaporation. The buildup of plant matter has to keep pace with the subsidence of the earth’ssurface, so sedimentary deposits or rising water levels don’t overwhelm the peat. Let’s assume optimum conditions. Beneath the ever-deepening layers of sand, silt and mud, most of the peat moisture is squeezed out. More heat and pressure furthers the transformation, first into lignite, a soft, brownish-black coal with a low carbon content, then black or bituminous coal, the type found in Nova Scotia and in most of the coal-bearing areas on the planet. A mineral that fuels economies, launches kingdoms and revolutionizes worlds.
    Coal wasn’t the only rock formed in the Carboniferous—the name given by scientists to the period running from 360 million to 280 million years ago—world. Basins were subsiding, infiltrated by upland streams that deposited their coarse sand and gravel loads, covered by rising seas that eventually retreated, leaving coastal plains that were again colonized by peat-forming vegetation. The pattern—coal seams, flood-plain mudstones, lake or marine lime-stones and riverbed sandstones—is visible in outcrops around the world, and is thought to be linked to the rising and falling sea level as the ice caps of the South Pole melted and grew when the climate shifted. Nowhere, though, can match Joggins as a time-lapsed snapshot taken as the world’s great coalfields were being formed.
    No wonder Joggins was so deeply embedded in Lyell’s thinking from that moment on. In 1852 he returned with another illustrious Nova Scotian scientist in tow. They had met a decade earlier, when Lyell made a brief stop before his trip to Joggins. In New Glasgow he dined at Mount Rundell, met the local mucky-mucks and paid a visit to a young man with a good fossil collection. “He looked over my specimens with appreciation,” John William Dawson wrote in his memoirs, “and listened with interest to what I could tell him ofthe geology of the beds in which they occurred.” Dawson, twenty-two, devoutly Christian, fluent in Latin and Greek and with a working knowledge of Hebrew, was freshly back from Edinburgh, Scotland, after his university studies had been interrupted by a family financial setback. At that point his startlingly varied career—geologist, paleontologist, author, publisher, politician, educational visionary, university president—was just beginning. His life-altering epiphany, on the other hand, had already occurred. “It happened, when I was a mere schoolboy,” Dawson wrote, “that an excavation in a bank not far from the schoolhouse exposed a bed of fine clay-shale which some of the boys discovered to be available for the manufacture of home-made slate pencils.”
    Dawson and his classmates used to amuse themselves by digging out flakes of the stone and cutting them into pencils with their pocket knives. One day Dawson was surprised to discover that one of the flakes “had on it what seemed to be a delicate tracing in black, of a leaf like that of a fern.” The riddle—real leaves or not, and if real, how did they come to be in the stone?—preoccupied his mind. Eventually his father sent him to the principal of a local grammar school, the astute Scotsman Thomas McCulloch. He “received me kindly, and assured me that the impressions were real leaves imbedded in the stone when it was being formed.” And Dawson’s life, quite simply, was never the same