The Rupnik line is a boundary line between two different types of rock layers. It's like the line between the sand and water at the beach. Only, instead of sand and water, it separates two different kinds of rock.
When scientists study the Earth, they often want to know the different layers that make up the crust. They use special tools to dig deep into the ground and take samples of the rocks. And they found that different rocks have different properties and characteristics.
The Rupnik line is a special boundary line that separates two types of rocks called mafic and felsic. Mafic rocks are dark-colored and are made mostly of iron and magnesium, while felsic rocks are light-colored and are made mostly of silica and aluminum.
So when a scientist looks at a cross-section of the Earth's crust, they can see where the Rupnik line is, and they know that on one side of the line, they'll find mafic rocks, and on the other side, they'll find felsic rocks.
Understanding the Rupnik line is important because it helps scientists understand how the Earth was formed and how it continues to change. Just like how the waves at the beach shape the sand and water, the different layers of rocks in the Earth are constantly shifting and changing, and the Rupnik line is an important clue in understanding those changes.