Rock materials, ranging in size from minute clay particles to large boulders, blanket the land surface in any area which has been invaded by a glacial ice mass. These deposits, known collectively as drift , are made up of crushed and mixed rock fragments picked up by the ice along its path.

The material dropped by a glacier is usually a mixture of particles and rocks of all sizes. This unsorted pile is called glacial till. Water from the melting ice may form lakes or other water features. A moraine is sediment deposited by a glacier.

Melting glaciers deposit all the big and small bits of rocky material they are carrying in a pile. These unsorted deposits of rock are called glacial till. A large boulder dropped by a glacier is a glacial erratic.

Glacial erratics are stones and rocks that were transported by a glacier, and then left behind after the glacier melted. Erratics can be carried for hundreds of kilometers, and can range in size from pebbles to large boulders. Scientists sometimes use erratics to help determine ancient glacier movement.

Glacial erratics, often simply called erratics, or erratic boulders, are rocks that have been transported by ice and deposited elsewhere. For example, an erratic could be a boulder of sandstone is picked up by a glacier, transported, and deposited on top of a limestone bedrock.

Powered by A moraine is material left behind by a moving glacier. This material is usually soil and rock. Just as rivers carry along all sorts of debris and silt that eventually builds up to form deltas, glaciers transport all sorts of dirt and boulders that build up to form moraines.

In geology (Udden–Wentworth scale), a boulder is a rock fragment with size greater than 256 millimetres (10.1 in) in diameter. In common usage, a boulder is too large for a person to move. Smaller boulders are usually just called rocks (American English) or stones (In British English a rock is larger than a boulder).

Glacier ice, like limestone (for example), is a type of rock. Glacier ice is actually a mono-mineralic rock (a rock made of only one mineral, like limestone which is composed of the mineral calcite). The mineral ice is the crystalline form of water (H2O).

So, any naturally occurring ice, the crystalline form of water (H2O), can be considered a mineral. Now coming to the concept of glaciers, the glacial ice, like granite, can be considered a rock.

A man in Hawaii has died after falling down a “lava tube” – a tunnel formed by volcanic eruptions – while trimming trees on his property. Police say the 71-year-old had apparently fallen about 22ft (7m) “through a soft area of ground”.

While your lungs would almost undoubtedly be irrevocably charred from the hot air above the lava (assuming relatively static air conditions over the lava), it takes about 80 seconds for the average human to fall unconscious from lack of oxygen, and I highly doubt your body will last that long.