6th Grade: How Much Do You Actually Know About Earth Science?

Explanation
Gaping Gill is an excellent example of a swallow hole. A swallow hole is a type of geological feature that forms when water from the surface disappears underground through a vertical shaft or hole. Gaping Gill is a large cave system in Yorkshire, England, where a stream disappears into a vertical shaft, making it a perfect example of a swallow hole.

Explanation
Limestone is best described as permeable because it is a sedimentary rock that is composed primarily of calcium carbonate. This composition allows water to easily pass through the rock, making it permeable. Limestone is often used as a building material and in the construction of roads and buildings due to its permeability, which allows for efficient drainage.

Explanation
Stalactites are formations that hang from the roof of a cave, typically made of calcium carbonate. They are formed when water containing dissolved minerals drips from the roof and leaves behind deposits that gradually build up over time. The word "icicles" in the question suggests that the formations in question are hanging from the roof, which is a characteristic of stalactites. Therefore, the correct answer is Stalactites.

Explanation
Yorkshire Dales is the correct answer because it is known for its spectacular limestone landscapes. The area is characterized by rolling hills, deep valleys, and unique rock formations, all formed by the erosion of limestone over millions of years. The limestone in Yorkshire Dales creates stunning features such as caves, cliffs, and waterfalls, making it a popular destination for hikers, nature enthusiasts, and photographers. The area's beauty and geological significance make it a prime location for exploring and appreciating limestone landscapes.

Explanation
Limestone was formed during the Carboniferous period. This period, which occurred approximately 358 to 298 million years ago, is known for the extensive deposition of limestone due to the abundance of marine organisms such as corals, mollusks, and algae. The Carboniferous period was characterized by warm and shallow seas, providing ideal conditions for the formation of limestone through the accumulation of calcium carbonate-rich remains of these marine organisms. This resulted in the formation of vast limestone deposits that are still present today in many parts of the world.

Explanation
Limestone areas usually have a dry surface because streams tend to disappear underground. Limestone is a porous rock that is easily dissolved by water, creating underground channels and caves. When it rains, the water quickly seeps into these underground channels, leaving the surface dry. This phenomenon is known as "karst" topography, and it is commonly found in limestone regions.

Explanation
Bare rock outcrops are called pavements because they resemble a solid, flat surface similar to a paved walkway or road. The term "pavement" is often used to describe rock formations that are exposed and visible, without any vegetation or soil covering them. These rock pavements can be found in various landscapes, such as deserts or high mountain areas, where weathering and erosion have removed the overlying materials, leaving only the bare rock surface exposed.

Explanation
Limestone is a type of sedimentary rock. It is formed from the accumulation of organic materials, such as shells and coral, as well as the precipitation of minerals from water. Over time, these materials become compacted and cemented together to form limestone. Sedimentary rocks are formed through the processes of weathering, erosion, deposition, and lithification, making limestone a fitting answer.

Explanation
Potholing is a popular hobby in limestone regions because limestone is a type of sedimentary rock that is easily eroded by water, creating underground caves and tunnels. Potholing, also known as caving or spelunking, involves exploring these underground systems, navigating through narrow passages, and discovering unique rock formations. The presence of limestone in these regions provides the perfect conditions for the formation of extensive cave networks, making potholing a popular and thrilling activity for adventure enthusiasts.

Explanation
Limestone is made of calcium carbonate. This is a common sedimentary rock that is formed from the remains of marine organisms such as coral and shells. Calcium carbonate is the main component of limestone and gives it its characteristic white color. It is also used in various industries, including construction and agriculture, due to its properties as a building material and soil conditioner. Calcium chloride, calcium dioxide, and calcium sulfide are not the correct answers as they do not make up limestone.