Rocks and Earth Materials

Coral reefs are constructed by tiny colonial marine animals called coral polyps, which extract calcium carbonate from seawater to build hard limestone skeletons. These organisms live in symbiosis with algae and create massive reef structures over time.

Oxygen makes up about 46-47% of Earth's crust by mass, making it the most abundant element. Silicon comes second at ~28%, while carbon and sulphur are much less abundant.

Gravity does not generate endogenic energy. This energy is mostly generated by radioactivity, rotational and tidal friction and primordial heat from the origin of the earth.

In rocks like granites, smooth surfaced and rounded small to big boulders called tors form due to exfoliation. These exfoliation tors result due to thermal expansion.

 Succession, starting at bare rock is termed as lithosere. In the case of a lithosere the pioneer species will be cyanobacteria and algae, which create their own food and water—i.e., they are autotrophic and so do not require any external nutrition (except sunlight).

The Earth's core is primarily composed of iron (about 85%) and nickel (about 10%), with smaller amounts of lighter elements. This metallic core generates Earth's magnetic field.

Basalt is formed from lava which cools slowly. Basalt originates from "hot spot" volcanoes, massive basalt flows and mid oceanic ridges.

Basalt is an extrusive igneous rock. It is the bedrock of the ocean floor and also occurs on land in extensive lava flow.

Metamorphic rocks form when existing rocks are exposed to heat and pressure deep within the Earth's surface.

Marble is a non-foliated metamorphic rock composed of recrystallized carbonate minerals.

As a mineral, it can form very pretty and sometimes extremely large crystals.

Metamorphic rocks are made by either heating up or squashing of the Earth's crust.

The application of directed pressure to a metamorphic rock results in the alignment of grains.

They are formed when sediment hardens into rock. Igneous magma at high temperature may penetrate into sedimentary rocks.

Diamond is made of only carbon.