Moho seismic discontinuity
Moho Seismic Discontinuity.
Also of special geological significance to the Tablelands is the famous Moho seismic discontinuity. Named after a Yugoslav seismologist who discovered it in 1909, the Mohorovicic Discontinuity, which reflects the different densities of the crust and the mantle, normally occurs at a depth of 35 km beneath the continents and about 10 km beneath the oceans. But here you can literally stand with one foot on the gabbro of the ocean crust and the other on the peridotite of the ocean mantle. It is because of this unusual sequence of rocks and other aspects of Gros Morne's geology and landscape that in 1988 Gros Morne was declared a UNESCO World Heritage Site..

Photo courtesy of Trevor Bell, © 1998.
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