Part 2

In Canada vast thicknesses of snow and ice accumulated until the weight of the ice finally caused it to flow slowly outward, mainly to the south (fig. 4). Rocks and surface materials of all types were picked up and carried by the glaciers for great distances before being deposited. Pieces of granite, quartzite, and native copper among the many local rocks and minerals are found in glacial deposits and indicate that at least part of these deposits came from the Great Lakes Region. The materials deposited range from clay-size minerals to large boulders.

a. Inferred limit of NEBRASKAN glaciation b. Inferred limit of KANSAN glaciation c. ILLINOIAN glacial advance d. SANGAMONIAN major drainage e. Maximum WISCONSINAN glacial advance f. Late WISCONSINAN Valparaiso front and Kankakee Flood

HOW DID ILLINOIS GET ITS SOILS?

Weathering and bacterial decay action have modified many of the loose, unconsolidated surface materials into soils. The present soils of Illinois are fertile partly because they have minerals and trace elements (minute amounts of elements such as copper, zinc, manganese) brought in by the glaciers from adjacent parts of the country. The youngest and most fertile soils occur in the northeastern part of the state and along the Illinois and Mississippi River valleys. These young soils are more fertile because the glacial deposits and loess (wind-blown silt) upon which they have developed are younger and fresher. The minerals and trace elements in these deposits have not been dissolved out to the extent that they have in the older glacial deposits and soils in other parts of the state.

ARE ANIMAL AND PLANT REMAINS FOUND IN THE GLACIAL DEPOSITS OF ILLINOIS?

Scattered mammoth (fig. 5) and mastodon remains have been found in glacial deposits at various localities in the state. Peat, which is an accumulation of partially decomposed plant materials, has been found, especially in the northern part of the state. It is marketed as an organic soil conditioner.

MINERAL WEALTH

HOW WEALTHY IS ILLINOIS IN MINERAL PRODUCTION?

In 1963, Illinois mineral production totaled approximately $615,000,000. This placed the state first as a mineral producer in the Upper Mississippi Valley and eighth in the nation.

WHAT MINERAL COMMODITIES ARE PRODUCED IN ILLINOIS?

Coal and petroleum, two of the world’s most important mineral resources, are produced in Illinois. Iron ore, another mineral of extreme importance, is brought into the steel mills of the Chicago and East St. Louis areas from deposits in Minnesota and Missouri. Some ore from foreign countries is also processed in these mills.

A great variety of mineral commodities are produced in Illinois. In the order of their 1963 value (fig. 6) they are (1) crude oil and natural gas, (2) coal, (3) clay products, (4) crushed stone and cement, (5) common sand and gravel, (6) special sands, (7) fluorspar, and (8) metals—zinc and lead.

HOW MANY ILLINOIS COUNTIES PRODUCE MINERAL COMMODITIES?

In 1963, 99 of the 102 counties of Illinois reported mineral production of one kind or another.

Petroleum and Natural Gas 36.3% Coal 31.9% Stone Products 15.2% Clay Products 8.8% Sand and Gravel 5.9% Fluorspar and Metals 1.9%

HOW MANY PEOPLE WORK IN THE MINERAL INDUSTRIES OF ILLINOIS?

In 1963, approximately 27,000 people worked in mines, quarries, oil fields, and direct processing operations such as cement and clay products plants and oil refineries. Many other persons were employed in transporting the materials and in plants and general offices.

HOW DOES THE FARMER IN ILLINOIS BENEFIT FROM MINERAL PRODUCTION?

The farmers of the state are among those receiving direct and indirect benefits from Illinois minerals. In 1963, more than 4,800,000 tons of agstone (crushed limestone and dolomite) were spread on Illinois fields to reduce acidity, maintain soil fertility, and improve crop production. Other stone and stone products are used in constructing farm buildings and facilities and in the maintenance of farm-to-market roads. In addition, petroleum products and coal provide energy to power the laborsaving devices that enable the farmer to increase his production and scale of operations.

PETROLEUM

WHAT IS PETROLEUM AND HOW IS IT FORMED?

Petroleum is a dark, oily fluid that is irregularly distributed in sedimentary rocks throughout the world. There are several ideas about the origin of petroleum. The most widely accepted of these is that billions of plants and animals lived and died in widespread seas and their remains decomposed and released fluid, fatty particles. These were distilled into “hydrocarbons” (a mixture of the elements hydrogen and carbon, such as gas and oil).

HOW AND WHERE DID OIL COLLECT IN ROCKS?

The hydrocarbons, or oil and gas droplets, were buried by countless tons of sediments that accumulated on ancient sea bottoms. As these sediments hardened into sedimentary rocks, the hydrocarbons were squeezed into whatever empty spaces were available in the rocks. As the layers of sedimentary rocks later became folded and broken, oil and gas droplets and salt water moved upward through any interconnecting open spaces. Some droplets escaped to the surface as “seeps,” but many were trapped when they came up against a nonporous barrier. Gas, being lighter than either oil or water, was trapped at the top, and oil was stopped in the middle, above the salt water. An accumulation of this kind is termed a “pool” or a “field.”

WHERE DID OIL ACCUMULATE IN ILLINOIS?

Conditions under which oil is found in Illinois (fig. 7) are as follows: (a) coral reefs, (b) anticlines (upfolds or arches of rock layers), (c) “pinching” or “lensing” out of dipping, overlapping porous rock layers, and (d) buried sandstone-filled ancient stream channels.

ARE THERE LAKES OR RIVERS OF OIL UNDERGROUND?

No. Oil and gas accumulate in the pores (openings) between silt and sand grains and in small openings in limestone and dolomite.