Lithogenic silica comes from the Greek words lithos, which means rock, and genesis, which means coming from. LSi is silica that originates from terrestrial sources of rock and soil, i.e. from silicate minerals

Silicate minerals

The silicate minerals make up the largest and most important class of rock-forming minerals, constituting approximately 90 percent of the crust of the Earth. They are classified based on the structure of their silicate group...

 and crystals.

In the marine silicon

Silicon

Silicon is a chemical element with the symbol Si and atomic number 14. A tetravalent metalloid, it is less reactive than its chemical analog carbon, the nonmetal directly above it in the periodic table, but more reactive than germanium, the metalloid directly below it in the table...

 cycle, LSi in the ocean is derived from rivers (5.6 Tmol Si/yr), eolian dust (0.5 Tmol Si/yr), hydrothermal vents (0.2 Tmol Si/yr), basalt

Basalt

Basalt is a common extrusive volcanic rock. It is usually grey to black and fine-grained due to rapid cooling of lava at the surface of a planet. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered basalt is black or grey...

 weathering

Weathering

Weathering is the breaking down of rocks, soils and minerals as well as artificial materials through contact with the Earth's atmosphere, biota and waters...

 (0.4 Tmol Si/yr), and from benthic fluxes (23 Tmol Si/yr) from the sediment into the ocean's interior (Tréguer et al., 1995).

LSi can either be accumulated "directly" in marine sediments or be transferred into dissolved silica

Dissolved silica

Dissolved silica is the form of water soluble silica as silicon hydroxide , which can be measured by standard analyses . However, The term dissolved silica is different from the silicate occurring as silicate minerals, which is a class of minerals forming rings, sheets, chains, and tetrahedrons...

(DSi) in the water column.