F-I

Fauna
Organisms, especially the organisms of a particular region or period, considered as a group.

Gastropod
Belonging to the phylum of Mollusca, gastropods are soft-bodied animals with a head, a foot, a visceral body mass and a mantle, often (but not always) protected by an external shell.

Hydrology
The science dealing with the properties, distribution, and circulation of water.

Hydrothermal
In a geological context, an adjective applied to rocks, ore deposits, and springs produced by heated water. Seafloor Massive Sulphide deposits form when high-temperature water (hydrothermal fluid), heated in the crust, precipitates metal sulphides leached from the surrounding rocks. 

Indicated Resource
A resource whose size and grade have been estimated from sampling at places spaced closely enough that its continuity can be reasonably assumed.

Infauna
Aquatic animals that live within the bottom substratum rather than on its surface.

Inferred Resource
A resource whose size and grade have been estimated mainly or wholly from limited sampling data, assuming that the mineralized body is continuous based on geological evidence.