lpetrich

Mecca's continental crust likely originated as some island arc about a billion years or so, about the age of Rodinia, and it became part of East Gondwana a few hundred million years later, as part of the formation of the Arabian-Nubian Shield. East Gondwana is now India, East Antarctica, Australia, and New Zealand, and it was likely India that plowed up Arabia.

I checked on reconstructions of Rodinia, and some of them mention Arabia, and some of them don't. Those that do mention Arabia place it at the edge, where new continental crust gets collected.

Columbia (supercontinent) is about 1.8 - 1.5 billion years old, and is likely older than Arabia.

Before that is Kenorland (2.7 billion years old), Ur (continent) (3 billion years old) and Vaalbara (3.6 billion years old).

Vaalbara is now parts of southern Africa (Kaapvaal) and western Australia (Pilbara).

North America Basement Rocks shows their history. The east, west, and south coasts date back to the Paleozoic or a little before, while the central and northern areas are older, with northern Canada having some of the Earth's oldest surviving rocks.

There are several other places with rocks dating from the Archean, but Arabia is not even close to any of them. Western South America, western Africa, central Africa, southern Africa, northern to eastern Europe, central and eastern Siberia and Asia, southern India, western Australia.

This page links to a nice map of the Precambrian cratons.

Steviepinhead

There conceivably could have been a point, early in the earth's history, after the earth cooled enough for water -- from out-gassing from the interior and perhaps infalling from comets -- not to immediately boil off, but before the first continents began emerging (lighter, granitic "continental" crust vs. denser, basaltic "oceanic" crust) and the tectonic cycle became established, that there might have been a world-covering ocean.

I seem to remember that some of the earliest-sampled mineral grains indicate the presence of water.

But I'm not sure how you would "prove" -- given the time depths involved, the extensive tectonic recycling of minerals, and the overall scantiness of the evidence -- that the detailed topography of the globe was ever such that you could describe a world ocean...

And as for the geomagnetic coincidence of the north pole of the spin axis and the "0" designation of the magnetic pole "lining up," that's purely temporary (since the magnetic poles wander and even reverse over time), as well as dependent on the arbitrary conventions whereby we number the lines of longitude. Like Greenwich Mean Time ...

One of those "even a broken clock will give the correct time twice a day" things. Every other place on the same line drawn through the true and magnetic poles would be just as "special" in this regard as Mecca.

credoconsolans

I know he's wrong, but what is this Muslim's guy's point? The first land mass developed wins?

lpetrich

Yes, that Mecca is such a holy place that it is on the Earth's first dry land.


However, since the oldest known continental crust is in northern Canada and western Australia, does that mean that Mohammed ought to have ridden caribou or kangaroos instead of camels?


And check out magnetic declination, the angle between the direction to the spin north pole and the direction of the local magnetic field, where both directions have been projected onto the local horizontal plane.

That Muslim gentleman was claiming that Mecca's magnetic declination is exactly 0 degrees, but it is now 3 degrees east. But the Earth's magnetic field changes over time, and in 1920, Mecca got close to 0, and in 1700, it got to around 15 degrees west.

Clinical

But Arabia has never been subjected to archaeological excavations like Canada and Australia, if at all.

Cycad

And your point is ?

Clinical

I am not promoting anything here, just stating the obvious.

premjan

Arabia certainly has a shitload of petroleum though that probably has nothing to do with age.

lpetrich

If you mean geological exploration, then you are just plain wrong. Arabia's oil fields were found with the help of a *lot* of geological exploration, and the Arabian-Nubian Shield has been researched a lot for clues as to how continents form. Since the continental basement rock is close to the surface there instead of being overlaid by thick layers of sedimentary rock, it's relatlvely easy to find such clues.

In fact, I did some searching, and it is rather easy for me to find geological maps of the Arabian peninsula.

anthrosciguy

Archaeology too. I don't know where Clinical got the idea that that area hasn't been archaeologically explored.