CHAPTER 6.  GEOLOGY AND MINERALOGY

One cannot fully understand life without understanding geology.  One cannot understand fully the process of evolution without understanding the movement of plate tectonics.  Geology is intimately related to evolution and ecology, certainly two of the most powerful forces affecting human development and history.

The authors have worked a great deal on the botany of the larger New York Metropolitan Region.  In this regard the study of both zoology (including humans) and botany is greatly aided by the study of the geology of the area.  Where biological species are located is not an accident but varies directly with the geology of the area.  We have found that the more we understand the basic geology of the larger New York Metropolitan area, the more we understand the distribution of biological species.    For instance, the Great Valley runs across the western edge of the larger New York Metropolitan area.  Here one finds plants associated with limestone areas.  This is good to know as it helps one understand why certain plants are found here that are not found in other areas of the region.  

In discussing human history, we will later see how the earth's geology has had a massive effect on the political systems of the various nations of the world.   We place political theory directly within an ecological context.  And this certainly explains why a chapter needs to be devoted to geology.  

This chapter was recently added and needs considerable work.  That's what happens with a living book on the web.  

Introduction to Mineralogy

There are some 2,500 different minerals.

Elements 92 of them;

copper, sulfur

Halides flourite

Oxides

Sulfides

Sulfates

Carbonates and Borates

Phosphates, Molybdates, Vanadates

Silicates quartz

Elements

I. Metals

uncombined; they have a shiny luster, are heavy, and have electrical conductivity; copper, silver, gold, lead, iron,

platinum;

II. Semimetals

These have a metallic luster, but oxidize easily. Examples include arsenic, antimony, selenium.

III. Nonmetals

carbon, sulfur

Halides

Oxides

simple

multiple

Sulfides, Sulphosalsts

Sulfates gypsum

Phosphates turguoise

Arsenates

Vanadates, chromates, molybdates, tungstates

Carbonates

calcite, dolomite, malachite, nitrates, borates, iodates

Silicates

About 75 percent by weight of the earth's crust is composed of the two elements oxygen and silicon. For the most part, oxygen and silicon occur in combination with other abundant elements such as aluminum, iron, calcium, sodium, potassium, and magnesium to form an important group of minerals called the silicates. A single family of slicate minerals, the feldspars, comprises about one half of the material of the earth's crust.

Introduction to silicates (6 spatial arrangements)

1) tectosilicates  --   quartz, microcline, orthoclase

2) phyllosilicates --   biotite, muscovite, serpentine

3) iniosilicates  --     hornblende

4) cyclosilicates --   beryl, axinite

5) neosilicates  --    olivine, zircon

6) neosilicates  --     topaz

1) quartz

chalcedony -- composed of extremely small fibrous crystals of

quartz

chert

flint

jasper

agate

2) feldspars

Feldspars are the most abundant constituents of rocks, composing about 60 percent of the total weight of the earth's crust.

a) orthoclase or potassium feldspar group (the potassium aluminosilicates)

b) plagioclase group (aluminosilicates of sodium and calcium)

anorthite

albite

3) Mica group

Mica is a silicate mineral having sheet structure.

Muscovite mica -- colorless or pale-colored

biotite mica -- dark colored

4) Ferromagnesian minerals

Hornblende -- amphiboles

Olivine

Augite -- pyroxene family

Others:

Garnet -- almandite

Chlorite

Clay minerals

Quartz

Amethyst

Calcite

Thirty-Nine of the Two Hundred Common Minerals

garnet, olivine, augite, hornblende, tremolite, serpentine, muscovite, beotite, pyrite, galena, rock crystal, sulfur, copper, graphite, gypsum, halite, microcline, opal, jasper, agate

Inner Circle

Atoms, Space Lattices and Crystals

There are thirty-two classes of crystals, but these are grouped into six systems.

1) linear

2) triangular

3) tetrahedral

4) octahedral

5) cubic

6) cubic close packing or hexagonal close packing

Physical Properties

hardness

cleavage

fracture

tenacity

Chemical Properties

fusibility

soluble in water

soluble in dilute hydrochloric acid

soluble in warm dilute hydrochloric acid

soluble in warm dilute nitric acid

solid solution

chemical alternation

Optical Properties

color

streak

luster

refraction

polarization

dispersion

Mineral Forming Environments

I. Metamorphic

magnetite, vesuvianite, tremolite, scapolite, chrysotele, kyanite, almadine, pyrite, staurolite, tremolite, dravite, talc, graphite, ciopside, wollastonite, dravite

II. Magmatic

labradorite, diamond, gabbro

A. Gabbroic

typically dark; native iron, pyrrhotite

B. Granitic Minerals

molybdenite, granite, sodalite, syenite, corundum, cancrinite

III. Pegmatite

A. Simple Pegmatite

beryl, almadine, muscovite, almadine, columbite, apatile,

quartz, microcline

B. Complex Pegmatite

muscovite, apatite, beryl, petalite, rose quartz

Large minerals

IV. Hydrothermal Environment

a hot, fluid residue, usually of magmatic origin, that is chiefly water that contains a rich supply of metallic elements

a) hypothermal -- great depth

millerite, pyrrhotite, nickeline, flourite

b) mesothermal -- shallow depths

phrrhotite, pyrite

c) epithermal

gold, cinnabar, mercury, barite, calcite, dolomite, orthoclase, flourite, quartz, silver, hessite

V. Hydrothermal and Metamorphic Environments

Franklin-Sterling Hill area of New Jersey

VI. Oxidation and Secondary Enrichment Environment

Hypothermal or other near to air and water may oxidize. It is chiefly the metallic elements that oxidize.

a) Intro

galena, wulfenite, siderite, pyrite, smithsonite, adamite,

cupurite, azurite, malachite

b) secondary enrichment

VII. Evaporite Environment

a) alkalic collection

halite, trona, gypsum

b) borate collection

boracite, borax

VIII. Volcanic (as in Paterson, NJ area)

Basalt area is coated with minerals. They are zeolites (chabazite, heulandite, mesolite, stilbite, and others). There are more than 60 species.

IX. Sedimentary

a) place minerals

gold, garnet, olivine, zircon, chromite, olivine, zircon, chromite

b) general collection

baurite, aragonite, magnesite, sulphur, flourite, calcite, dolomite, gypsum, galena, hematite, pyrite, hematite, manganite

 

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