Clay minerals exist as the end of the weathering cycle of feldspars and a few other minerals. Formed at depth under pressure these minerals are stable under conditions of high pressure and temperature. When they are exposed to conditions at the earth's surface they begin to change chemically and structurally into the clays.
Shale is the most abundant sedimentary rock. Formed at the earth's surface largely from clay, what do you think will happen to them if through subduction in PLATE TECTONICS they are taken back into the high T and P zones? YES! They become feldspars again in METAMORPHIC ROCKS! So there is the ROCK CYCLE! In its Simplest Form... IGNEOUS IS WEATHERED INTO SEDIMENTS WHICH MAKE SED RX which are then subducted and become METAMORPHIC which if they are melted become IGNEOUS and ROUND AND ROUND>
ROUND AND ROUND... 5 is sediments incl claystones coming from 4... Sed Rocks going to 6, other sed rocks, drawn down in 7, turned to 8 Meta rx, squeezed or melted into granite, melted into #1 Magma, 2 and 3 diff Ig rx weathered into 4 sed RX and then #5 sediments. Got it?
“The rock cycle is a basic concept in geology that describes transitions through geologic time among the three main rock types: sedimentary, metamorphic, and igneous. Each rock type is altered when it is forced out of its equilibrium conditions. For example, an igneous rock such as basalt may break down and dissolve when exposed to the atmosphere, or melt as it is subducted under a continent. Due to the driving forces of the rock cycle, plate tectonics and the water cycle, rocks do not remain in equilibrium and change as they encounter new environments. The rock cycle explains how the three rock types are related to each other, and how processes change from one type to another over time. This cyclical aspect makes rock change a geologic cycle and, on planets containing life, a biogeochemical cycle.” Wiki..
What are clay minerals? Well, first of all they are minerals. DEF we all learn in Earth Science… “A mineral is an inorganic solid, found in the earth, with definite physical properties… crystal shape, hardness, breakage or cleavage etc, which are the outward manifestation of DEFINITE CHEMISTRY. AND THIS MEANS CRYSTALLINE!
LIKE ALL DEFINITIONS THERE”S A LOT OF EXCEPTIONS AND BUTS< but this fits clay minerals. INORGANIC? ONE HYPOTHESIS on the ORIGIN OF LIFE is that clays got involved with the origin of RNA because of their active SURFACES! We are going to use theirs in our wellness and beauty discipline.
Found on earth? CLAYS FOUND ON MARS indicate active water chemistry going on there! At least in the past!
CLAY FLOORING in MEXICAN HOME.
Clays are classified as PHYLLOSILICATES… Phyllo means Leaf, silicate means the basic structure is made of tetrahedrons of Silicon and oxygen… and they are arranged in flat sheets… like pressed leaves. Tetrahedon is the shape of a Four sided pyramid.
MEMORIZE THIS DIAGRAM FOR NEXT TIME. JUST kidding. THE NAMES IN BOLD FACE are those minerals we will use in our pursuits! Also Dickite. How could we not talk about Dickite!?