One hundred million years and 1000km: Exploring the Ediacaran-Cambrian boundary in Newfoundland

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After a long drive from St. John’s to Fortune Head across the vast, bleak limestone barrens of the Burin Peninsula, we set up camp close to a river. A quick dusk investigation in the shallows revealed some bedload blocks to be heaving with early Cambrian trilobite fragments.

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Dr Richard Thomas (the provincial geologist in charge of Ediacaran and Cambria stratigraphy around the coast of Newfoundland) was a brilliant field companion to Amelia Penny and I (in blue) as we sampled inside the Fortune Head ecological reserve. Here, my head is at the approximate height of the Ediacaran-Cambrian boundary global boundary stratotype section and point (GSSP) in lower member 2 of the Chapel Island Formation. This boundary has been set at approximately 541 million years old.

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Clambering over the early Cambrian sediments also provided good opportunity for whale sightings. We were lucky enough for a split second humpback whale exposé as it surfaced to breathe less than 20m from the shore in the deep coastal waters (unfortunately my camera trigger finger failed the task).

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Flowering carnivorous sundew is a beautiful but lethal attraction for resting insects. Measuring just a centimetre or two in height, their finger-like stems can be seen protruding from the sphagnum moss along the clifftops of Fortune Head.

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Our second sampling section, Little Dantzic Cove, was a 1.5hr walk from the nearest usable road. This abandoned farmhouse marked the halfway point, with the islands of St Pierre et Miquelon on the horizon. These islands are a self-governing overseas territory of France.

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Gannets perform an elaborate display, plunging to attack the unsuspecting shoal of fish immediately off the coast of Little Dantzic Cove on the Burin Peninsula.

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We observed this flock of gannets tracking the shoal closer and closer to our cliff top viewpoint.

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The harsh coastal winds and winter temperatures stunt the trees atop the cliffs.

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Early Cambrian shallow marine stromatolites grew as a thin, slimy, hummocky layer on the seafloor, now preserved in thin limestone beds alongside abundant small shelly fossils.

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A bedding surface riddled with shallow marine trace fossils which mark the earliest Cambrian substrate revolution. A Canadian dollar rests within a fracture for scale. This surface outcrops approximately 20m above the Precambrian-Cambrian boundary contact at Grand Bank Head.

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On our return drive to the conference in St John’s, we passed by the most easterly point in North America and Canada (excluding Danish-controlled Greenland), Cape Spear.

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At the conference dinner, we were all given the impassable opportunity of becoming ‘Honorary Newfoundlanders’ in a ceremony called a ‘Screech-in’. This involved reciting some verse, drinking a native rum (screech), eating a piece of bologna and… kissing a dead cod…

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A post-conference fieldtrip provided the opportunity to visit one of the most important localities in Ediacaran stratigraphy; Mistaken Point. Professor Graham Budd sits before the Mistaken Point D surface which contains hundreds of examples of Fractofusus alongside other forms including Bradgatia. The E surface is atop the ~2m cliff at the far end of the D surface.

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Specimens of Charniodiscus spinosus (stalked) and Fractofusus misrai (horizontal) on the Mistaken Point E surface

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Seeing the iconic locality at Mistaken Point, of which I’d heard so much about since beginning my work on the Ediacaran Period, was absolutely the most eye opening and inspiring experience of the trip. It was also the perfect way for it to end. Witnessing these beautiful, enigmatic fossils first-hand stoked the fire of motivation with respect to my last year of PhD and thesis write-up.

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