Laterite in the context of "Lavaka"

Boehmite or böhmite is an aluminium oxide hydroxide (γ-AlO(OH)) mineral, a component of the aluminium ore bauxite. It is dimorphous with diaspore. It crystallizes in the orthorhombic dipyramidal system and is typically massive in habit. It is white with tints of yellow, green, brown or red due to impurities. It has a vitreous to pearly luster, a Mohs hardness of 3 to 3.5 and a specific gravity of 3.00 to 3.07. It is colorless in thin section, optically biaxial positive with refractive indices of nα = 1.644 – 1.648, nβ = 1.654 – 1.657 and nγ = 1.661 – 1.668.

Boehmite occurs in tropical laterites and bauxites developed on alumino-silicate bedrock. It also occurs as a hydrothermal alteration product of corundum and nepheline. It occurs with kaolinite, gibbsite and diaspore in bauxite deposits; and with nepheline, gibbsite, diaspore, natrolite and analcime in nepheline pegmatites. Industrially, it is used as an inexpensive flame retardant additive for fire-safe polymers.

Stygofauna are any fauna that live in groundwater systems or aquifers, such as caves, fissures and vugs. Stygofauna and troglofauna are the two types of subterranean fauna (based on life-history). Both are associated with subterranean environments – stygofauna are associated with water, and troglofauna with caves and spaces above the water table. Stygofauna can live within freshwater aquifers and within the pore spaces of limestone, calcrete or laterite, whilst larger animals can be found in cave waters and wells. Stygofaunal animals, like troglofauna, are divided into three groups based on their life history – stygophiles, stygoxenes, and stygobites.

1. Stygophiles inhabit both surface and subterranean aquatic environments, but are not necessarily restricted to either.
2. Stygoxenes are like stygophiles, except they are defined as accidental or occasional presence in subterranean waters. Stygophiles and stygoxenes may live for part of their lives in caves, but don't complete their life cycle in them.
3. Stygobites are obligate, or strictly subterranean, aquatic animals and complete their entire life in this environment.

Extensive research of stygofauna has been undertaken in countries with ready access to caves and wells such as France, Slovenia, the US and, more recently, Australia. Many species of stygofauna, particularly obligate stygobites, are endemic to specific regions or even individual caves. This makes them an important focus for the conservation of groundwater systems.

Sdok Kok Thom (Thai: สด๊กก๊อกธม, Sadok Kok Thom, pronounced [sādók kɔ́k tʰōm]; Khmer: ស្តុកកក់ធំ, Sdŏk Kák Thum [sɗok kɑk tʰum]), or Sdok Kak Thom, is an 11th-century Angkorian temple in present-day Thailand, located about 34 kilometres (21 mi) northeast of the Thai border town of Aranyaprathet. The temple is in Khok Sung District, Sa Kaeo Province, near the village of Ban Nong Samet. It is regarded as the largest Angkorian temple in eastern Thailand. The temple was dedicated to the Hindu god Shiva. Constructed by a prominent priestly family, Sdok Kok Thom is the original site of one of the most illuminating inscriptions left behind by the Khmer Empire, which ruled much of Southeast Asia from the end of the 9th century to the 15th century.

Built of red sandstone and laterite, the temple is a prime example of a provincial seat of worship during the empire's golden age. It is small by the standards of the major monuments in Angkor, the empire's capital, but shares their basic design and religious symbolism. In its 11th century heyday during the reign of King Udayādityavarman II, the temple was tended by its Brahmin patrons and supported with food and labor by the people of surrounding rice-farming villages.

Saprolite is a chemically weathered rock. Saprolites form in the lower zones of soil profiles and represent deep weathering of the bedrock surface. In most outcrops, its color comes from ferric compounds. Deeply weathered profiles are widespread on the continental landmasses between latitudes 35°N and 35°S.

Conditions for the formation of deeply weathered regolith include a topographically moderate relief flat enough to prevent erosion and to allow leaching of the products of chemical weathering. A second condition is long periods of tectonic stability; tectonic activity and climate change can cause erosion. The third condition is humid tropical to temperate climate.

The Ethiopia-Yemen Continental Flood Basalts were erupted during the Oligocene. They cover an area of about 600,000 km in Yemen and Ethiopia, with an estimated volume of greater than 350,000 km. They are associated with the Afar Plume and the initiation of rifting in the southern Red Sea and Gulf of Aden.

In Ethiopia flood basalts cover an old erosion surface with occasional flat areas or peneplains. Burial of old surfaces by lava has preserved laterite soils in both Yemen and Ethiopia.