New details about Earth’s hotter twin geology include some surprises about Earth’s hotter twin geology, which describes the movement of Earth’s shell, according to new research funded by NASA.

Scientists expect Venus’ outermost layer to become thicker over time, thicker, because it obviously lacks the force to bring the shell back to the inside of Earth. However, this article was published in Nature Communications and proposed a crust metamorphosis process based on rock density and melting cycle.

The Earth's rocky shell consists of large scale plates that move slowly, forming folds and faults in a process called plate tectonics. For example, when two plates collide, the lighter plate slides onto the dense plate, forcing the layer below it to slide downward into the mantle. This process is called subduction and helps control the thickness of the earth's crust. The rocks that make up the bottom plate undergo changes due to rising temperature and pressure as it penetrates deep into the earth. These changes are called metamorphosis, which is one of the causes of volcanic activity.

By contrast, Venus' shell is a piece of debris, and there is no evidence that the subduction caused by plate tectonics like Earth. The paper uses modeling to determine that its shell averages about 25 miles (40 kilometers) and up to 40 miles (65 kilometers).

"That's so thin, given the conditions on Earth," Filiberto said. "It turns out that according to our model, as the shell becomes denser, the bottom becomes so dense that it either breaks and becomes part of the mantle or becomes hot enough to melt." So, although Venus doesn't have a moving plate, its shell does experience spoilage. This discovery is an important step in understanding geological processes and the evolution of the earth.

"This rupture or melting can bring water and elements back into the interior of the earth and help drive volcanic activity," Filiberto added. "This gives us a new model of how materials return to the interior of the earth, another way to make lava and stimulate volcanic eruptions. It makes for how geology, crust and atmosphere on Venus work together to reset the playing field."

The next step is to collect direct data on the Venus crust to test and refine these models, he added. Several upcoming missions, including NASA's Davinci (a survey of precious gases, chemistry and imaging by Venus) and Veritas (Venus launch, radio science, Insar, Insar, topography and spectrum), as well as working with ESA (European Space Agency) to study the Earth's surface and atmosphere. These efforts could help confirm whether processes such as metamorphosis and recycling are actively shaping today’s Venus crust and reveal how such activity is related to volcanic and atmospheric evolution.

"We don't actually know how much volcanic activity is on Venus," said Filiberto. "We assume there are a lot of things, and the research says there should be, but we need more data to be sure."

Melissa Gaskill
NASA Johnson Space Center

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Victoria Segovia
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