PARADOX IN STRATIGRAPHY:
WHERE ARE THE ANCIENT ROCKY LANDSCAPES AND SEASHORES?
There is an obvious paradox in stratigraphy. Along the ancient unconformities we should find a multitude of ancient rocky seashore. Rocky seashores seems to be recorded exclusively in the Tertiary time with a few exceptions. So to say the paradox is also related to the science of geomorphology. Moreover, Palaeozoic and Mesozoic unconformities do not present too many real paleorelieves or at least differential eroded surfaces like the ones of our modern topography. Should we wonder why paleogeomorphologist is not a common trade in earth science? Geodoxa is filming unconformities around the world to stir up this controversy and to build new research partners.
Revisiting Siccar Point - A New Perspective
Siccar Point is the most famous outcrop in the history of modern geology. For centuries geologists visit the site influenced by the same old ideas not noticing some of the very odd elements of this unconformity. It seems as if the old Silurian strata/slabs were thrusting upward like pistons disturbing non stop the Upper Devonian sedimentation.
That might explain another oddity: The Silurian basement bears no trace of chemical alteration by weathering. Yes there is a differential eroded surface of the Silurian but not a one as seen today. The basal conglomerate of the Upper Devonian reminds the violent erosion of our modern "wadi" (flooding river in desert) and for that reason the desert/wadi interpretation is commonly accepted today. If the Silurian bedrock was tectonically thrusting up during the fast Devonian sedimentation one might draw two conclusions:
1- The violent upheaval of the topography should be the main cause for the flooding/debris flow not the one triggered by weather fluctuation.
2- This sort of syn-tectonic sedimentation make this phenomenon an event uncommon today.
Ogmore by sea 2016