Assembling Asia: Ring of Fire - tectonic journeys in East Asia

[@a.modestproposal2038]

I recently discovered your channel and am enjoying all your videos so much, thank you! One view and I was a subscriber. For paleomagnetism I was curious to hear some remarks on how geomagnetic reversals are taken into account. I guess that reversals happen so quickly that field inclination is effectively stable over geologic time? And even if the field polarity is not, polarity differences are random and mostly irrelevant? Thank you for sharing you passion for geology.

[@robbutler2095]

The rate at which the dipole flips is a matter of pretty intense research over the past decades - it continues today, with numerical simulations of the Earth's dynamo. A challenge is gaining robust data calibrated against time in the geological record... but when viewed on the (say) 10kyr time-scale, the reversals look essentially "instantaneous" ... but in detail the magnetic field (and therefore dynamo) varies dynamically over 10s-100s years - principally detected by variations in field strength through time (of course measured at the remove of the Earth's surface...

[@jonrolfson1686]

During my first assignment in Southeast Asia, in Northern Thailand, in 1971, a similarity of the region’s parallel ranges and valleys to topography that was to be seen in Nevada and Western Utah’s Basin and Range Province was noticeable. In the intervening decades this similarity was occasionally a matter for random musing, but, not being a geologist, nor even a scientist of any particular sort, my mild curiosity about the matter went long unsatisfied. As the story of India’s headlong rush to its collision with the pre-existing Asia trickled into the consciousness of amateur geologists and geographers, and the related accounts of terrane accretion east of the Indian Ocean, the difference of the origins of those parallel mountain and valley structures in Southeast Asia from the stretching and faulting that produced the superficially similar topography in the western US became clear. Your further elaboration provides familiar Cambodian and Thai place names to attach to the accreted terranes.

[@robbutler2095]

An interesting personal historical reflection - thanks for sharing it!

[@joewalker4710]

Very nice video. Geology is so fascinating. Will watch more on your channel

[@susanbone3634]

Thanks so much for this and other videos you've posted. It's fascinating stuff; presented clearly in a straightforward way

[@andrezcaradepez6344]

Great video, learned a lot and was very fascinated !

[@robbutler2095]

great - glad you found the film useful.

[@Julian_Wang-pai]

Thank you, thank you, thank you. I live in northeastern Thailand close to the suture bounding the western and southern perimeter of Isaan - amongst sentinel L. Cretaceous escarpment. You have answered a number of questions I've pondered about the local geology. But I still have one yet to answer. These escarpments extend eastwards into Laos and Cambodia and consitute a colossal fluvio-deltaic system. Was it the biggest ever yet identified on this planet?

[@robbutler2095]

Certainly the post-late Triassic deposits represent thick accumulations of fluvial etc strata - perhaps up to c 6 km thick (with more added in the Tertiary as the greater Himalayan ranges shed sediment). But thick continental deposits are not uncommon around the world - including the "Old Red Sandstone" (Devonian) of central Scotland!

[@TheAnarchitek]

I think the more interesting question is "What put them in motion?"

[@robbutler2095]

We didn't start the fire, it's been always burning since the World's been turning (apologies to Billy Joel)

[@TheAnarchitek]

@@robbutler2095 Not even close. Something tore hell out of Earth, more than once, or even twice, and we live in the debris field.

[@UCannotDefeatMyShmeat]

@@TheAnarchitekah, world building for your next analog horror series I see