Deposition Associated with Glaciation

Deposition Associated with Glaciation 

The Glacial Conveyor 

The glacial conveyor and the formation of lateral and medial moraines on glaciers.

Glaciers can carry sediment of any size and, like a conveyor belt, transport it in the direction of flow (that is, toward the toe;  figure above a). The sediment load either falls onto the surface of the glacier from bordering cliffs or gets plucked and lifted from the substrate and incorporated into the moving ice. Geologists refer to a pile of debris carried by or left by glaciers as a moraine. Sediment dropped on the glacier’s surface moves with the ice and becomes a stripe of debris. Stripes formed along the side edges of the glacier are lateral moraines. When a glacier melts, lateral moraines lie stranded along the side of the glacially carved valley, like bathtub rings. Where two valley glaciers merge, the debris constituting two lateral moraines merges to become a medial moraine, running as a stripe down the interior of the composite glacier (figure above b). Trunk glaciers created by the merging of many tributary glaciers contain several medial moraines. Sediment transported to a glacier’s toe by the glacial conveyor accumulates in a pile at the toe and builds up to form an end moraine.

Oil and Gas

Oil and Gas

What Are Oil and Gas? 

For reasons of economics and convenience, industrialized societies today rely primarily on oil (petroleum) and natural gas for their energy needs. Oil and natural gas, both fossil fuels, consist of hydrocarbons, chain-like or ring-like molecules made of carbon and hydrogen atoms. Chemists consider hydrocarbons to be a type of organic chemical.

Some hydrocarbons are gaseous and invisible, some resemble a watery liquid, some appear syrupy, and some are solid. The viscosity (ability to flow) and the volatility (ability to evaporate) of a hydrocarbon product depend on the size of its molecules. Hydrocarbon products composed of short chains of molecules tend to be less viscous (meaning they can flow more easily) and more volatile (meaning they evaporate more easily) than products composed of long chains, because the long chains tend to tangle up with each other. Thus, short-chain molecules occur in gaseous form (natural gas) at room temperature, moderate-length-chain molecules occur in liquid form (gasoline and oil), and long-chain molecules occur in solid form (tar).