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REDDING SURVEY

CAPE MENDOCINO SURVEY

UKIAH SURVEY

YORKVILLE SURVEY

SANTA ROSA SURVEY

CLEAR LAKE SURVEY

MAGNETIC FIELD,

IN NANOTESLAS

Topography from 30-meter digital elevation model (DEM). 

North American Datum of 1927 (NAD27).

Topography from 30-meter digital elevation model (DEM). 

North American Datum of 1927 (NAD27).

SAN ANDREAS FAULT

MAACAMA FAULT

BARTLETT SPRINGS FAULT

SAN ANDREASs FAULT

Point

Arena

Shelter

Cove

Ukiah

Willits

Lake

Pillsbury

Clear

Lake

Point

Delgada

Cape

Mendocino

Mendocino

Fort

Bragg

Petrolia

Fortuna

Elk

Boonville

Cloverdale

Healdsburg

Bodega Bay

Covelo

Laytonville

Garberville

Laguna

Point

Fort Ross

0123456789 10 MI

Data compiled by Victoria E. Langenheim

GIS database and digital cartography by 

Victoria E. Langenheim

Edited by Theresa Iki; digital carographic 

production by K. Nimz

Manuscript approved for publication 

October 28, 2011

A. Color Mosaic Aeromagnetic Map of the Northern Coast Ranges, California, Superposed on Shaded-relief Topography

Quaternary fault from Jennings and Bryant (2010)

Aeromagnetic survey boundary (see table 1 

for survey specifications)

Contours of total magnetic field 

intensity relative to the International

Geomagnetic Reference Field. 

Contour interval is 10 nanoteslas. 

Hachures indicate closed magnetic 

lows. Contours were computer 

generated based on a 200-m grid 

Coastal Belt Thrust from Wagner and Bortugno 

(1982), Jayko and others (1989), and McLaughlin and 

others (2000)

PACIFIC OCEAN

124°22'30" 15' 7'30" 124° 52'30" 45' 37'30" 30' 22'30" 15' 7'30" 123° 122°52'30"

124°22'30" 15' 7'30" 124° 52'30" 45' 37'30" 30' 22'30" 15' 7'30" 123° 122°52'30"

38°22'30"

30'

37'30"

45'

52'30"

39°

7'30"

15'

22'30"

30'

37'30"

45'

52'30"

40°

7'30"

15'

22'30"

40°30'

38°22'30"

30'

37'30"

45'

52'30"

39°

7'30"

15'

22'30"

30'

37'30"

45'

52'30"

40°

7'30"

15'

22'30"

40°30'

CALIF.

MAP LOCATION

Data compiled by Victoria E. Langenheim

GIS database and digital cartography by 

Victoria E. Langenheim

Edited by Theresa Iki; digital cartographic 

production by K. Nimz

Manuscript approved for publication 

October 28, 2011

CALIF.

MAP LOCATION

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MAGNETIC FIELD, 

IN NANOTESLAS

PACIFIC OCEAN

Aeromagnetic and Aeromagnetic-based Geologic Maps of the 

Coastal Belt, Franciscan Complex, Northern California

By

V.E. Langenheim, R.C. Jachens, C.M. Wentworth, and R.J. McLaughlin

2011

124°22'30" 15' 7'30" 124° 52'30" 45' 37'30" 30' 22'30" 15' 7'30" 123° 122°52'30"

124°22'30" 15' 7'30" 124° 52'30" 45' 37'30" 30' 22'30" 15' 7'30" 123° 122°52'30"

U.S. Department of the Interior

U.S. Geological Survey

38°22'30"

30'

37'30"

45'

52'30"

39°

7'30"

15'

22'30"

30'

37'30"

45'

52'30"

40°

7'30"

15'

22'30"

40°30'

38°22'30"

30'

37'30"

45'

52'30"

39°

7'30"

15'

22'30"

30'

37'30"

45'

52'30"

40°

7'30"

15'

22'30"

40°30'

Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not 

imply endorsement by the U.S. Government

This map was printed on an electronic plotter directly from digital files. Dimensional calibration may vary 

between electronic plotters and between X and Y directions on the same plotter, and paper may change 

size due to atmospheric conditions; therefore, scale and proportions may not be true on plots of this map.

For sale by U.S. Geological Survey, Information Services, Box 25286, Federal Center, Denver, CO 80225, 

1–888–ASK–USGS

Digital files available at http://pubs.usgs.gov/sim/3188/

Suggested Citation: Langenheim, V.E., Jachens, R.C., Wentworth, C.M., and McLaughlin, R.J., 2011, 

Aeromagnetic and aeromagnetic-based geologic maps of the Coastal Belt, Franciscan Complex, 

northern California: U.S. Geologic Survey Scientific Investigations Map 3188, pamphlet 20 p., 3 sheets, 

various scales, and database, available at http://pubs.usgs.gov/sim/3188/.

B. Merged Shaded-relief Aeromagnetic Map of the Northern Coast Ranges, California. Mendocino, Redding, and Yorkville Surveys Upward 

Continued 150 M to Match Average Height Above Ground for the Ukiah Survey

SAN ANDREAS FAULT

MAACAMA FAULT

BARTLETT SPRINGS FAULT

Ukiah

Willits

Lake

Pillsbury

Clear

Lake

Mendocino

Fort

Bragg

Elk

Covelo

Laytonville

Laguna

Point

Shelter

Cove Point

Delgada

Cape

Mendocino

Petrolia

Fortuna

Garberville

east-west 

flightline

artifacts?

northeast-southwest flightline

artifacts?

SAN ANDREAS FAULT

Point

Arena

Boonville

Cloverdale

Healdsburg

Bodega Bay

Fort Ross

Quaternary fault from Jennings and Bryant (2010)

Contours of total magnetic field 

intensity relative to the 

International Geomagnetic 

Reference Field. Contour interval is 

10 nanoteslas. Hachures indicate 

closed magnetic lows. Contours 

were computer generated based on 

a 200-m grid

Coastal Belt Thrust from Wagner and Bortugno 

(1982), Jayko and others (1989), and McLaughlin and 

others (2000)

Scientific Investigations Map 3188

Sheet 1 of 3

Pamphlet accompanies map

1 0 1 2 43 5 6 7 8 9 10 KILOMETERS

SCALE 1:250 000

1 10 2 3 4 5 6 7 8 MILES

1 0 1 2 43 5 6 7 8 9 10 KILOMETERS

SCALE 1:250 000

1 10 2 3 4 5 6 7 8 MILES