Surtsey (“Surtr‘s island” in Icelandic, pronounced /ˈsʏr̥tsei/) is a volcanic island located in the Vestmannaeyjararchipelago off the southern coast of Iceland. At Coordinates: , Surtsey is the southernmost point of Iceland. It was formed in a volcanic eruption which began 130 metres (426 ft) below sea level, and reached the surface on 14 November 1963. The eruption lasted until 5 June 1967, when the island reached its maximum size of 2.7 km2 (1.0 sq mi). Since then, wave erosion has caused the island to steadily diminish in size: as of 2012, its surface area was 1.3 km2(0.50 sq mi). The most recent survey (2007) shows the island’s maximum elevation at 155 m (509 ft) above sea level.
So the island appeared at the end of 1963 and 54 years later it looks old.
One of the main geological problems is explaining the appearance of rounded boulders and cobbles, gravels etc, as beaches shown below:
Rounded boulders and cobbles produced by wave action? Except no one has actually observed this happening. One day its naked lava etc surrounded by the ocean, and next visit, magically, the boulders and cobbles are present.
These mega-particles or mega-grains, are not the result of prolonged fluvial transport, principally because water is incapable of moving these objects. Yet there are rare accounts of storms lifting up larger rocks onto wave-cut platforms, but simply lifting a massive rock is different to rolling it along or back and forth to abrade it from an angular block to a rounded one. This one has me stumped, to be frank, and it also leads to a problem of explaining beds of conglomerate well away from oceans in older stratigraphy on land. Are those conglomerates the result of prolonged fluvial transport? No, because some years back when I was ferrying heavy mineral samples from the King George Diamond Project across the Drysdale River crossing on Carson River Station in the North East Kimberley of Western Australia, I noticed an old bull-dozed ramp formed from blading rounded cobbles and sand from the river bed. Cyclonic activity and regular monsoonal weather seemed incapable of moving anything of this artefact, meaning that flowing water was not actually capable of moving the basalt cobbles or fine quartz sand.
The question in my mind was wondering just what would it take for the Drysdale River flow regime to erode and move these in situ boulders, gravels and sands?
Scientifically the situation is that riverine or hydraulic flow moves channel bed-load down stream and thus eroding and comminuting the load by abrasion and impact into smaller object, a sort of quasi autogenous grinding process minus the necessary slurry needed in mine milling operations.
Symbolically:Process A ======>> Sediment over time, or A –> G
Is it being observed? Well no, because when a cyclone or intense monsoon event occurs, the last place one needs to be is in a roiling, turbulent fast flowing river, so direct observations are never made.
Or the theory is wrong, and some other process is producing rounded boulders and cobbles from fresh lavas and tuffs such as seen at the newly formed Surtsey Island off Iceland. Flowing water certainly isn’t, and electric currents working in dark current mode during storms are some what difficult to observe as well…….
Or we can stop thinking and defer to authority and accept its pronouncements.