Intro to Geology: Exam #2l; Groundwater, Karst Geology, and Geothermal System

What is an aquifer?

An aquifer is a body of water underground. It is an area of stored groundwater.

what properties define a good aquifer?

high porosity, high permeability, large thickness and lateral extent

What properties define a poor aquifer?

ow permeability and low useful porosity

What are the three types of aquifers?

unconfined, confined, perched

how are aquifers they impacted by pollution or overuse?

pollution from contaminants like pesticides, industrial chemicals, and manure seeping into the groundwater

What is an aquiclude/aquitard?

An impermeable rock that does not transmit water

what are aquiclude/aquitard properties?

saturated geologic formations that are virtually impermeable, preventing the transmission of groundwater.

What are springs?

natural outlets where groundwater emerges at the land's surface

How do they relate to the potentiometric surface?

when the potentiometric surface rises above the land surface, the water is forced to flow out, forming a spring

What are artesian wells? How do they relate to the potentiometric surface?

a well that taps into a confined aquifer where water is under natural pressure, so it rises to the surface without a pump.

How do Artesian wells relate to the potentiometric surface?

The potentiometric surface is the imaginary level that water would rise to in an artesian well due to this pressure; the artesian well's ability to draw water to the surface

What is a geyser?

A fountain of water and steam that erupts from the ground

What is a mud pot?

a hot spring that contains more mud than water

What is a hot spring?

a spring of naturally hot water, typically heated by subterranean volcanic activity.

What is a fumarole?

vent for volcanic gases

How is geyser, mud pot, hot spring, and fumarole different and similar?

all hydrothermal features formed when underground water is heated by magma, but they differ in what reaches the surface.

How do hot springs and geysers form and what are their differences?

both form when underground water is heated by geothermal energy, but their key difference lies in their underground plumbing systems

What do each of these indicate about connections between groundwater & subsurface geology?

The connection between groundwater and subsurface geology indicates the potential for groundwater flow and how it moves. High porosity and permeability allow for significant groundwater storage and low permeability is impede.

What controls impact the nature of hydrothermal systems like these?

a heat source, a source of fluids, and the permeability of the rock that allows for circulation.

What are lines of evidence that Yellowstone is still active as a hot spot & potentially explosive super volcano?

the presence of hot and molten rock (magma) beneath the caldera, the existence of thousands of hydrothermal features, high rates of heat flow, frequent earthquakes, and continuous ground deformation.

What is an Earthquake swarms?

many small earthquakes, especially in Yellowstone caldera, indicate movement of magma & hydrothermal fluids beneath surface.

What is an Ground deformation correlation?

EQ patterns often correlate with uplift or subsidence events of caldera: Measured by GPS & satellite radar. Uplift indicates magma/hydrothermal fluid accumulation; subsidence suggests fluid withdrawal & cooling. - Also Yellowstone Lake is tilting!

What is Hydrothermal explosion craters?

Changes in local topography indicate shifting fluid pathways

What is Hydrothermal and geochemical changes?

observed as changes in geyser activity: Variations in eruption frequency, duration, or height can reflect changes in subsurface heat or water supply.

What is Water chemistry shifts?

Si, Cl, & other elements in hot springs indicate new magmatic inputs or changes in subsurface.

What is temp changes?

Thermal monitoring shows fluctuations that signal changing heat flow or fluid pathways

What is volcanic and magmatic evidence?

Geophysical studies (seismic tomography) reveal a partially molten layer beneath Yellowstone, confirming hotspot activity

What is past caldera eruptions?

Stratigraphic evidence of massive eruptions averaging 600,000 years aligns with hotspot magmatic cycles. Current eruption gap is 640,000 years - so slightly overdue

What is heat flow measurements?

Elevated heat flux over caldera is direct evidence of ongoing hotspot activity.

What is thermal imaging?

Satellites detect surface temperature changes in geysers, fumaroles, and hot springs

What do humans do to alter groundwater systems?

Excessive pumping, salt water intrusion, altering flow paths

What are some changes that have happened on campus over the last 30 years that have influenced surface and groundwater?

increased urbanization and development, leading to more impervious surfaces on campus and in the surrounding area, which increases stormwater runoff and erosion

What are some ways that groundwater can become depleted?

Over-pumping, natural factors and human activities

What is meant by impervious surfaces and why is it a big deal?

hard, non-porous surfaces like roofs, roads, and parking lots that prevent rainwater from soaking into the ground. it increases and faster runoff leading to floods and erosion.

What are some potential solutions to these issues?

reducing the amount of pavement and using permeable materials for driveways and patios, while also incorporating green infrastructure like green roofs and rain gardens.

What are some causes of groundwater contamination?

Human activities like waste disposal, landfills, mining and etc. Natural sources and accidental spill

How & where do caves form?

Caves form when acidic water dissolves soluble rocks like limestone, creating passages underground.

What can be concluded if you see a dry cave?

indicate that the cave's formation level is now above the current water table, meaning the water that created it has since receded or changed course

What are stalactites & stalagmites and where do they form?

Stalactites hang from cave ceilings, while stalagmites grow from cave floors, both formed by mineral-rich water dripping and depositing calcite

What do they tell us about climate change?

reveal past temperatures, rainfall patterns, and abrupt climate shifts

What is karst topography?

a unique landscape formed primarily by thedissolving action of surface and groundwater on soluble bedrock.

how might you identify it from a topographic map?

by interpreting symbols, colors, and especially the contour lines, which represent elevation and land shape.

What are some hazards associated with groundwater and karst terranes?

sinkholes (collapsed and flooding), groundwater pollution, foundation problems and underground features like caves and shafts

What is perhaps the biggest geologic hazard that faces Shippensburg? - Why?

sinkholes, which are a major risk due to the area's geology of limestone and dolomite bedrock.