"Roxbury puddingstone, the mottled rock quarried nearby and used for much of the old church masonry in Boston, formed 600 million years ago in violent submarine landslides off the coast of a barren volcanic microcontinent that rifted off Africa. This is so long ago thatin the course of the perpetual wander of continentsthe whole thing happened somewhere near the south pole."
"By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today. This is the rock that pokes out from underneath the fallen leaves and at the edges of Dunkin' parking lots in the Boston area. Very little else has survived the intervening half-billion-year eon here, save a superficial veneer from the extremely recent last ice ageone that is surely doomed in the next few dozen millennia or so."
Greater Boston features aging buildings, crooked gravestones, and old churches built from very ancient rock. Roxbury puddingstone originated about 600 million years ago in submarine landslides off a volcanic microcontinent that had rifted from Africa. Those sediments hardened, rode a tectonic plate across an ancient ocean, and later became attached to equatorial North America long before dinosaurs existed. Exposed puddingstone appears in local streets and parking edges today. Almost nothing else from that vast interval remains locally, aside from a thin, geologically recent veneer left by the last ice age.
Read at www.scientificamerican.com
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