麻豆淫院

For the last century, 脡mile Argand's theory on the formation and geological support system of the massive Himalayan mountain range has remained the predominant explanation widely accepted among geologists. This theory states that the ongoing collision of the Indian and Asian continental plates forced the crusts of the two plates to double in thickness and that this ultra-thick crust alone holds up the region's mountains, which were formed from these colliding structures.

However, some scientists have pointed out flaws in this theory, suggesting that it doesn't quite make sense. One argument is that crust thicker than around 40 kilometers would not have the ability to sustain a plateau the size of Tibet, and Argand's theory implies that the crust is somewhere around 70鈥�80 kilometers thick.

Some degree of skepticism of Argand's theory has piled on over the years as more and more studies find conflicting evidence, like the geochemical and seismic data showing the presence of mantle rock in places that it shouldn't be.

Meanwhile, a new study, in the journal Tectonics, claims to have a better theory about what is going on under the world's tallest mountain range.

To attempt to better understand the crustal dynamics of the Indian and Asian plates, the researchers performed more than 100 2D numerical simulations with varying crust and mantle properties. They then compared the simulations to seismic tomography and receiver function data, as well as geochemical rock signatures.

The simulations showed that instead of a hyper-thickened crust, the most likely result of the plates colliding was actually a kind of "crust-mantle-crust" sandwich鈥攔eferred to as crustal doubling, with a sliver of more rigid Asian mantle between the Indian and Asian crusts.

The simulations show that the Indian crust slid beneath the whole Asian lithosphere, which includes the crust and upper mantle. The Indian crust then liquefied due to the high temperatures at such depths, and parts of the crust rose to the area underneath the mantle section.

The study authors explain, "A far more plausible mechanism to double the Himalayan-Tibetan crust is by viscous underplating of the Indian crust beneath the Asian lithosphere, not crust. In this scenario, the Indian crust provides buoyancy and the Asian mantle provides strength to raise and support the Himalayan-Tibetan topography."

Such an explanation fits better with prior studies, like those showing mantle rock closer to the surface than expected with Argand's theory. Further work might incorporate 3D modeling to capture more detailed geological heterogeneities. The work has led to a better overall understanding of mountain building processes and might have potential for understanding other regions as well.

The study authors write, "If correct, this model transforms our understanding of the dynamical mechanisms underpinning the generation of Earth's most towering mountain range and has profound implications. For instance, the long-standing debate about the partitioning between Asian upper- and lower-crustal flow and the strength of the Asian crust during the growth of Tibet should be recast to account for viscous underplating of buoyant Indian (not Asian) crust underneath Asian lithosphere (not crust)."

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