‘Flesh’ atop of the ‘bones’ of bedrock geology

Surficial geology is the study of loose, unconsolidated material overlying the bedrock foundation. These layers were deposited, rearranged and eroded by glaciers, fluctuating sea level, streams, landslides, and bulldozers. While bedrock geologists tend to think in time-frames of millions of years, the surficial story is usually faster paced, taking place over millennia and mere centuries.

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Surficial versus bedrock geology

 

While bedrock geologists tend to think in time-frames of millions of years, the surficial story is usually faster paced, taking place over millennia and mere centuries. On the map above, I’ve divided landforms into 5 age groups (geol_age field):

  • triassic: applied only to a couple bare-bedrock roches moutonees near Mendenhall Glacier
  • early holocene: marine, glacial and alluvial formations dating back to shortly after the great ice age, ~10,000 years ago
  • neoglacial: dating to just the last few millennia
  • little ice age: mostly formed since peak of the last glacial advance in the mid-1700s
  • anthropocene: built or excavated features mostly since 1950.

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More Information

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Mendenhall Glacier: Aerial Perspectives

This booklet of maps and images spanning the past century shows the Mendenhall Glacier’s retreat and the forest succession, while also providing information on the area’s geology.  The Mendenhall Glacier was the destination selected by the Glacier habitat group of the STREAM: Pedagogy of Place Institute, July 17-19, 2013.  You’ll find information about bedrock geology and surficial geology, and you’ll also find historical photographs of the Mendenhall.

Download Here (5MB): PDF_Download

 

 

Natural History of Juneau

Natural History of Juneau Trails: A Watershed Approach

$24.00

If you or someone on your gift list enjoys Juneau’s outdoors, this book is for you.  It is packed with information for the hiker, hunter, or any student of the outdoors.  Richard’s insightful text, full color maps, and dozens of recent and historic photographs explain the landforms, water features, and natural environments Juneau residents navigate every day.  Dive in for a whole new understanding of the areas you love to explore, with one of Southeast Alaska’s foremost naturalists.

Reading Southeast Alaska's Landscape

Reading Southeast Alaska’s Landscape

$10.00

This book tells the constantly evolving story of geology in our region.  It tracks how bedrock forms, how glaciers wax and wane, and how rivers and the sea shape our land.  While the book offers a general introduction to bedrock and surficial geology, it also focuses in on regional geologic highlights.  It is a must-have for nature enthusiasts in Southeast.

 

 

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Spring 2011 Newsletter, Geology and life: Connections between the living and non-living world

In this newsletter, Richard Carstensen seeks to answer a seemingly simple question: how do living things respond to geologic landforms and rock types?  His essay explores the interactions between living and non-living things in Southeast Alaska.  You will also find Discovery News, and a short write-up by Scott Burton on the popular trail game Camouflage.

Download Here (1.1MB): PDF_Download

 

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Surficial Geology Map

From Richard Carstensen:
Here’s a surficial geology map for the Juneau area. I used most of the geologic surface types of R.D. Miller, USGS, 1972, Some types were collapsed into broader categories: especially the many varieties of colluvial and raised-marine landforms. On the other hand, unit boundaries have been considerably adjusted and fine-tuned from 2013 DEM-generated bare-earth. Miller’s original map is available as a pdf from ADNR.
Zoom with your mouse roller. Click on any of the color coded units for a pop-up listing landform type, generating agent, and geologic age. For a legend, open >>, upper left. To view this map in ArcGISonline, select view larger map.