Geology and Hydrology: Rock Dating, Glaciers, and Groundwater

How do caves and karst topography form?

They form when acidic groundwater dissolves limestone underground.

How old is a rock if the parent-to-daughter ratio is 1/7 and the half-life is 50 million years?

150million years

Nonconformity

Sedimentary rocks overlie igneous or metamorphic rocks.

Unconformity

A break in the geologic record created when rock layers are eroded or when sediment is not deposited for a long period of time.

Types of desserts

Subtropical, rain shadow, coastal or polar

Disconformity

Has parallel layers with a time gap

wave refraction

the bending of waves so that they move nearly parallel and slow down as they approach shallow waters (shoreline)

Density, salinity and temperature are related because

Seawater becomes denser when salinity increases or temperature decreases

Dessert abrasion

Occurs when wind-driven sand wears down rock surfaces

How do caves and karst features form, what is the type of rock they form in?

Caves develop when acidic groundwater dissolves limestone

Limestone dissolution creates karst landscapes

Effects of extensive freshwater pumping

Over-pumping can lower water table, causing land subsidence

Creates cone of depression

Saltwater intrusion

What is an angular unconformity?

Tilted rocks overlain by flat ones.

What do longshore currents do?

They move sand along the coast and create features like spits and sandbars.

What does relative dating determine?

The order of events.

What does absolute dating provide?

The actual age in years.

How do upper ice and deep ice behave in glaciers?

Upper ice behaves brittle and cracks; deep ice flows plastically.

What are the effects of extensive freshwater pumping?

Over-pumping can lower the water table, cause land subsidence, and create cones of depression.

What is an aquifer?

A rock layer that stores and transmits groundwater easily.

How do desert soil and temperate forest soil differ?

Desert soils are very dry, thin, and low in organic matter; temperate soils are rich and moist.

What is permeability of a rock?

How easily water flows through a rock.

What is the difference between ordinary wells and artesian wells?

Ordinary wells require pumping; artesian wells flow naturally due to pressure.

What types of deserts exist?

Subtropical, rain shadow, coastal, or polar.

What happens to glaciers when accumulation exceeds ablation?

Glaciers advance.

What is ablation?

Loss of ice and snow from glaciers and snowfields through processes like melting, evaporation, and calving.

What is an aquitard?

A layer that slows or blocks groundwater movement.

What is porosity of a rock?

The amount of empty space in a rock.

What are veritifacts?

Wind-shaped rocks.

What are yardangs?

Ridges carved by wind erosion.

What are continental shelves?

Shallow edges of continents.

What is nonconformity in geology?

Sedimentary rocks on top of igneous or metamorphic rocks.

What causes desertification?

Overgrazing, deforestation, poor farming, climate change, and soil erosion.

What are abyssal plains?

Flat deep-sea floors.

What is a half-life?

The time required for half of a radioactive isotope to decay into its stable product.