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    This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.
    Northwest Geology Field Trips, by Dave Tucker, is licensed under a Creative Commons Attribution-Noncommercial- Share Alike 3.0 United States License. You can use what you find here, repost it with attribution to the author, "remix" it for your own purposes, but may not use it with the intent of making money off of it.

    EDUCATORS: Please feel free to use anything you find here that is useful to your mission educating people about Earth science. E-mail me if it would help to have a larger or higher-resolution version of any of the images. tuckerd at geol dot wwu dot edu

Washington interactive geology map

I get a lot of emails asking about on-line geologic maps. The Washington State Department of Natural Resources has a great resource. It is the Washington Interactive Geology Map. It allows you to select map scales, map background (topographic? street map? terrain?) and the type of geology you are interested in (faults? surface geology? tsunami inundation zones? landslide? volcanic vents?). You can play with scales and move around on a map of the entire state. The portal is here, which connects you to several interactive maps: http://www.dnr.wa.gov/ResearchScience/Topics/GeosciencesData/Pages/geology_portal.aspx

If you choose the Interactive geology map, you end up here: https://fortress.wa.gov/dnr/geology/?Theme=wigm

The menu lets you select lots of features to turn on or off. You have to play with it a bit to get it really

screen capture of a portion of the interactive geology map.

screen capture of a portion of the interactive geology map. Click to enlarge.

figured out, but it isn’t difficult. The figure above shows the screen set for western Whatcom County. In this menu I selected ‘surface geology’, 1:24,000 and 1:100,000 scale geologic map overlays. 1:24,000 scale maps are only available for some areas, and show up in the image as an area with denser information; an example is in the center, and lower left. You can zoom in on those for more detailed geology. You can turn text labels for geologic units on or off to reduce clutter. The more data you request, the slower the system is to load. I also clicked the box for ‘seismogenic features’, which turned on the blue dashed diagonal faults on the left edge of the screen.

Interactive map showing mapped faults in wesern Whatcom County.

Interactive map showing mapped faults in wesern Whatcom County. Click to enlarge.

This figure shows a much simplified view of seismogenic features only, in the same area. There are several fault strands in the Kendall area at center, as well as the same three faults between Gooseberry Point and Blaine. All the other information is turned off for clarity.

REQUEST TO READERS. If you experiment with any of the other interactive maps on the portal page (tsunami inundation zones, coal mine inventory map, natural hazards, seismic scenarios, etc. please consider writing a comment below about how useful you found it.

Google Earth Washington Geology Map program

Google Earth screen shot showing Skagit County, Washington, geology

Google Earth screen shot showing Skagit County, Washington, geology. Click to enlarge any image. The Eocene Rhyolite place mark is my own.

Google Earth (GE, download it here) can be a great tool for looking at landforms. Washington State’s Department of Geology and Earth Resources has prepared a set of 1:100,000 geologic map overlays for the state’s counties. Find them here. Scroll down to the very bottom of the webpage to find “Google earth 1:100,000 scale Surface Geology 3d overlays” . Download the kmz file, which automatically opens in Google Earth. The various geologic layers are listed in GE’s ‘Places’ menu. You can click the boxes to show, or hide, whichever aspect you are interested in. For instance, the default map units are opaque, and you can see no landscape through them. You can adjust the transparency of the overlay, or even hide the map colors (under the ‘geologic units’ submenu) so all you see are the welter of contacts. A tutorial video by DNR on YouTube explains usage of the Google Earth geology overlay. This uses the Whatcom county kmz file as an example.

The transparency slider.

Unit transparency slider: ‘Geologic units’ is highlighted, then click the blue box next to the magnifying lens, and tweak the slider.

The tutorial isn’t very clear on adjusting transparency, so I’ll go over that first. First, click the ‘geologic units’ box in the menu, then the blueish icon next to the magnifying glass at the bottom of the menu. Use your mouse to adjust the slider until you are happy, or at least reasonably satisfied.

GE Skagit geology, with unit polygons turned off. Lines are contacts and faults. Unit names remain.

GE Skagit geology, with unit polygons turned off. Lines are contacts and faults. Unit names remain.

GE Skagit county showing only occurences of Twin Sisters Dunite.

GE Skagit county showing only occurrences of Twin Sisters Dunite.

You may choose to use the menu to show only faults, or only unit labels, or only certain units. However, there may be a TON of map polygons associated with each unit, and each isolated occurrence of, say,

‘Darrington phyllite’ has its own box in the places menu. I’m still getting the hang of it. It is worthwhile to download one county’s geology .kmz file, and zoom out so the entire county is visible. Then you can click the various units listed in the expanded menu to see just what map unit, and where, that unit box belongs to. If you click on the name of a unit on the GE map screen, a balloon pops up with more, or less, information on the unit (see the figure below). Perhaps there will be only a tiny bit of information that is of little use, or maybe you’ll get lucky and get unit name, age, and even a reference. You can always rename units to make it easier to locate them in the places menu. Suppose you are interested in Darrington phyllite but only in the Blanchard Mountain area. You can find one of the mapped phyllite polygons on the GE image, click on the colored map polygon to see which label in the menu at left is highlighted, then rename that menu item ‘ Darrington SE Blanchard’ or whatever sort of personal label makes sense for your interests. You want to set aside some free time to play around with this program.

Burlington Hill (see page here on NW Geo FT blogs) with a unit clicked for info.

Burlington Hill (see page here on NW Geo FT blogs) with a unit clicked for info. Not all of the unit callouts will have this much information.

This is definitely a useful reconnaissance tool. These .kmz overlays take up a fair amount of space, so when you open GE you’ll need to be patient as they all load. The more county GIS layers you load into your GE program, the more slowly GE will open. You can always choose not to keep them in your GE Places menu, and access the maps from the DNR website each time instead. But then you have to tell GE not to save the overlay in the temporary places list when you close GE. Suit yourself. I use this tool a lot to help plan out field trips, so I’m the sort of person who would leave it loaded on GE in my computer.

Finding online geologic information: a Washington Department of Geology and Earth Resources pdf.

The Washington DGER website is being revised. In the interim, a quick way to find links to geologic maps and all manner of information about things such as coal mine history is in this pdf. Click the link below to go to the pdf.

finding_geologic_information (2)

Thanks to my friend Stephen Slaughter at DGER for steering me to this pdf.

North Cascades geology map added to listings

Welcome to many new subscribers who have come aboard in the past month.

Click on the post title above  to go directly to the blog and recent posts.

I have added the 2009 Geologic map of the North Cascades to the Geo-guidebooks and Maps page of this blog. View the page here. This is a wonderful map, by the premier North Cascades bedrock geologists of the US Geological Survey. I posted on it earlier, but didn’t realize that it includes 100 color photos of North Cascades geology, keyed to the different map units. It is a fabulous document; the paper copy comes with CD and a wall map. Follow the link above for the map’s URL and for ordering info.

Geologic map of the North Cascades. 33 x 50 " paper map. Click to enlarge.

Geology basics- a new page on the website

By popular request, I’ve begun a new page on the website, GEOLOGY BASICS, accessed from a tab at the top of each page. I’ll try not to turn this into a textbook-length effort. The first explanation has been added, which discusses the concepts of strike and dip of sedimentary layers, with illustrations and links to trips where you can see good examples.

I’ll add to this page sporadically. If I gloss over a concept in a posted field trip that you think deserves inclusion in these primers, send a comment and I’ll see what I can do.

Take me to the new page!


New USGS North Cascades Geologic map

USGS geologists Ralph Haugerud and Rowland Tabor have prepared a 1:200,000 scale map of North Cascades geology. It is published by the USGS and is available for download here. A wonderful added attraction- the map’s website includes over 100 color photos of North Cascades geology and landscapes.

The title is Geologic Map of the North Cascades Range, Washington (Scientific Investigations Map 2940). It carries a 2009 publication date, but has just come out. (Continued below image)

The new map by Haugerud and Tabor

The new map compiles several 1:100,000 scale geologic maps: Mount Baker, Robinson Mountain (Pasayten area), Sauk River, Twisp, Skykomish River, Chelan, Snoqualmie Pass, and Wenatchee. The map area extends from Ellensburg north to the international boundary, and from just east of the lowlands of the Salish Sea to Lake Chelan. It is accompanied by a nontechnical pamphlet written in a style similar to that used in the popular book, Geology of the North Cascades, that is, educational and appropriate to the nonprofessional citizen geologist.

FLASH NEWS– the Mountaineers have Tabor and Haugerud’s republished Geology of the North Cascades, the essential geologic primer and hiking guide to the mountains.