Geologists shed light on the tibetan plateau origin puzzle

Earth's geographical surfaces have been formed over millions of years, and various current theories aim to explain their formation. The most popular theory, called the "plate tectonics theory," states that Earth's outermost layer is a dynamic system consisting of slowly moving plates, also known as "tectonic" plates.

As theses plates move, they come close to each other and collide, or drift away from or slide past the other, causing tension or rupture along their boundaries. If two colliding plates face enormous compression force along the rupture line, a slab of the earth would uplift. The uplifted piece of land gives rise to geographical structures such as mountains or plateaus on the landscape of the earth.

The Tibetan Plateau, the highest plateau in the world, is believed to have been formed through one such tectonic process, when the Indian and Eurasian continental plates collided with each other. Interestingly, the landscape of this enigmatic plateau consists of various unusual geological structures that have baffled geologists globally.

For example, many independent geological units of different structures and ages are placed next to each other in a way that cannot be explained by a single tectonic event as per the existing theory. Intrigued by this, in a new study published in Earth Science Frontiers, a group of scientists at the China University of Geosciences, led by Dr Liu Demin, investigated in detail the geological structures of the southern Tibetan Plateau. Talking about their motivation, Dr Demin says, "The southern Tibetan Plateau has a complicated geological structure, which cannot be explained by the existing 'plate tectonics' theory. Our study uses a new idea to explain some unusual tectonic structures that are part of the southern Tibetan Plateau."

To begin with, the scientists analyzed ancient tectonic ruptures in the form of "boundaries" between the distinct geological regions. The "South Tibet detachment system" (STDS) is one such boundary that runs parallel to the Himalayan range for more than 2,000 km. The researchers analyzed the geological data of STDS and other structures in the region, such as the Rongbu Temple normal fault and the Main Central Thrust (MCT), to trace the possible chain of events related to the evolution of these boundaries.

They speculated that instead of a single "collision-compression" process (as per the existing theory), these boundaries were created in different periods altogether, through a series of tectonic events that date back to the early Cenozoic era (a geological era that extends from 66 million years ago to the present day) and occurred in multiple stages.

According to this model, called the "opening-closing" theory, the upper layer or "crust" of a prehistoric ocean called the "Neo-Tethys" ocean expanded or "opened," and a part of the oceanic crust moved under the other, resembling a "closing" movement. The continental plates too followed a similar process of "opening and closing" as they moved towards and away from each other. This chain of events gave rise to the structures of the Tibetan Plateau. Using this model, the scientists were able to deduce that the Rongbu Temple normal fault and the MCT were formed earlier than the STDS was.

Further, they revealed that two tectonic units, klippes and windows, in the Chomolungma region were actually the result of gravitational gliding (as opposed to compression, as previously believed) and thus should be characterized as extensions and slips, respectively. Dr Demin further explains, "Thermal energy and gravitational potential energy in the deep earth played a key role during this opening-closing evolutionary process."

The geology of Earth's surfaces has changed over millions of years through continuous evolutionary processes. In this study, scientists unraveled part of the mystery surrounding the complex geological structures of the southern Tibetan Plateau.

Dr Demin concludes, "A deeper understanding of the 'opening-closing' process requires us to focus more on the detailed geological record for evidence of continuous rather than temporal processes." The research team now plans to study the differences between the opening-closing view and the plate tectonic theory in detail, to shed further light on the genesis of the Tibetan plateau.

Research Report: "Discussion on the Cenozoic tectonic evolution and dynamics of southern Tibet"

Related Links
Cactus Communications
Tectonic Science and News

Tweet

Thanks for being there;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Monthly Supporter
$5+ Billed Monthly

paypal only

SpaceDaily Contributor
$5 Billed Once

credit card or paypal

Which factors control the height of mountains?
Potsdam, Germany (SPX) Jun 15, 2020
Which forces and mechanisms determine the height of mountains? A group of researchers from Munster and Potsdam has now found a surprising answer: It is not erosion and weathering of rocks that determine the upper limit of mountain massifs, but rather an equilibrium of forces in the Earth's crust. This is a fundamentally new and important finding for the earth sciences. The researchers report on it in the scientific journal Nature. The highest mountain ranges on Earth - such as the Himalayas ... read more