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All News and Pages Related to "karst"

Allamakee County, Iowa

Posted on June 19th, 2015

KARST TERRAIN Karst terrains form by the dissolving of limestone or dolomite by groundwater. Typical features of karst terrains are caves, sinkholes, and springs. Many sinkholes have developed in the Galena Group in Allamakee County. Ludlow Township contains the most sinkholes in the state, with over 3,000 sinkhole identified.

Paleokarsts in Iowa

Posted on March 24th, 2015

Paleokarsts in Iowa by Robert M. McKay Following heavy rain, a muddy torrent of water laden with dislodged soil, twigs and leaves rushes down a gully and spills over a lip of rock, disappearing into a dark echoing hole. Crashing to the bottom of the pit, the flow continues outward and downward along narrow passageways […]

FAQs

Posted on April 30th, 2014

Have a question about Iowa geology? Here are some answers to frequently asked questions.  Are there dinosaur fossils in Iowa? What are the fossils of Iowa? Are there any meteorites in Iowa? What are geodes and how do they form? What are those strange boulders in fields? What is the midcontinental rift? When did oceans […]

Geologic Hazards

Posted on April 30th, 2014

Earthquakes Iowa Geological Survey geologists have information on historic Iowa earthquakes and significant earthquakes in other areas of the midcontinent. Only 12 earthquakes with epicenters in Iowa are known in historic times. The first known occurred in 1867 near Sidney in southwest Iowa, the most recent in 1948 near Oxford in the east-central part of […]

Geophysics

Posted on April 30th, 2014

The Iowa Geological Survey (IGS) incorporates electrical geophysics into a host of geologic and hydrogeologic research projects.  Geophysical surveys provide a continuous model of the shallow subsurface, complementing traditional point data. Subsurface materials can be characterized by their ability to conduct or resist electrical current.  Physical and chemical properties such as grain size, moisture content, mineralogy, and […]

General Geology

Posted on April 30th, 2014

Mineral, Rock, and Fossil Identification Geologists at the Iowa Geological Survey regularly identify rocks, minerals, and fossils that are brought into our office.  If you are not able to stop by our office, send photos of the specimen via email.  Please make sure that the photos capture all aspects of the specimen, are in focus, […]