Professor Emeritus of Earth and Environmental Sciences

James T. Gutmann
Department of Earth and Environmental Sciences
Wesleyan University
Middletown, CT 06459 USA

Education

BA from Amherst College
PhD from Stanford University

Professional Activity

Jim Gutmann taught physical geology, mineralogy, volcanology, and igneous and metamorphic petrology at Wesleyan University. He has retired from teaching but continues decades of research on the Pinacate Biosphere Reserve in Sonora, Mexico, an area that is now a UNESCO World Heritage Site. Ongoing projects there include the age of Pinacate volcanism and the geochemistry and origin of Pinacate volcanic activity.

This Web Site

The purpose of this web site is to post some Pinacate geologic images that may be of interest to others. References to many JTG publications on Pinacate geology are also provided below all the thumbnails.

Photographs of the Pinacate

The Pinacate volcanic field from an orbital spacecraft
This image of the Pinacate was taken in the early morning light. North is up, approximately. The Gran Desierto de Altar is west of the Pinacate. Adair Bay on the Gulf of California lies southwest of the volcanic field, and the course of the Sonoyta River is evident to the east. MacDougal Crater can be seen at the northwestern edge of the lavas and is a circular maar 1 mile in diameter. Image courtesy of NASA.



Click on the twenty-one pictures below to see larger images
and more detailed captions.

(© Copyright 2000, 2016 James T. Gutmann. All rights reserved.)

Please contact me via Wesleyan.edu if you would be interested in a copy of any of these photos.
References to many refereed publications on Pinacate geology, some cited in the captions, are listed in chronological order below the thumbnails.

Aerial view looking SSE across MacDougal Crater to the Sierra Pinacate on the right. Note the hundreds of cinder cones. Click on the image for more details.
The Carnegie Peak cinder cone and its debris flow. Click for more details.
Two of the eight Pinacate maars: Molina (foreground) and MacDougal Craters. Click for more details.
MacDougal Crater from its rim in the morning light.
MacDougal Crater and Volcán Santa Clara.
Cerro Colorado tuff cone seen from the northeast. La Laja cone, evidently the youngest eruption in the Pinacate, lies between Cerro Colorado and the Sierra Pinacate in the distance.
Cerro Colorado and Playa Diaz to the northwest.
Looking NNW across Sykes Crater toward Badilla Crater.
Looking NW along the steep outer slopes of the cone surrounding Sykes Crater.
Crater Elegante, seen here from the SW, is 1.6 km (1 mi.) across from rim to rim and 244 m (800 ft.) deep. Note the "bathtub ring" of lake sediments all around its inner walls. Click for more details.
A cinder cone seen in cross section in the SE walls of Crater Elegante.
Basalt dike injected radially out from the vent of the cinder cone in El Elegante and looking like a sword plunged horizontally into the cinders and snapped off at its hilt.
Moon Crater, a small maar, and its central cinder cone.
Tecolote Cone and its many associated lava flows and collapse features.
Looking north to Mayo Cone across Tecolote's late eruptive vents and the rafted masses of cinder.
A pressure ridge on the Ives flow in the southern Pinacate. Unlike most Pinacate lavas, the Ives flow is a pahoehoe flow rather than an aa flow.
A spatter cone and spatter tube on the Ives pahoehoe flow.
La Laja Cone, perhaps the youngest eruption in the Pinacate, as it appeared in 1970.
A cross section through a zoned basalt dike whose lava contains many large crystals of feldspar (labradorite).
Pinacate labradorite megacrysts can be almost perfectly formed and terminated.
Polarized-light microscopic view of a fragment of the earth's mantle carried up from 30 km below the Pinacate volcanic field.

Selected publications on the Pinacate Volcanic Field

Gutmann, J.T., 1974, Tubular voids within labradorite phenocrysts from Sonora, Mexico: American Mineralogist, v.59, p. 666-672.

Gutmann, J.T., and Martin, R.F., 1976, Crystal chemistry, unit cell dimensions, and structural state of labradorite megacrysts from Sonora, Mexico:  Schweiz . Mineral . Petrogr. Mitt., v. 56, p. 55-64.

Gutmann, J.T., 1976, Geology of Crater Elegante, Sonora, Mexico: Geol. Soc. America Bull., v. 87, 1718-1729.

Gutmann, J.T., 1977, Textures and genesis of phenocrysts and megacrysts in basaltic lavas from the Pinacate volcanic field: Am. Jour. Science., v. 277, p. 833-861.

Gutmann, J.T. and Sheridan, M.F., 1978, Geology of the Pinacate volcanic field, Sonora, Mexico:  Arizona Bureau of Geology and Mineral Technology Special Paper 2, p. 47-59.

Gutmann, J.T., 1979, Structure and eruptive cycle of cinder cones in the Pinacate volcanic field and the controls of Strombolian activity: Jour. Geol., v. 87, p. 448-454.

Gutmann, J.T., 1986, Origin of four- and five-phase ultramafic xenoliths from Sonora, Mexico: American Mineralogist, v. 71, p. 1076-1084.

Lynch, D.J., and Gutmann, J.T., 1987, Volcanic structures and alkaline rocks in the Pinacate volcanic field of Sonora, Mexico: in Davis, G.H., and VandenDolder, E.M., eds., Geologic Diversity of Arizona and its Margins, Arizona Bureau of Geology and Mineral Technology Special Paper 5, p. 309-322.

Lutz, T.M., Zhang, D., and Gutmann, J.T., 1989, Statistical analysis of vent locations in the Pinacate volcanic field, Sonora, Mexico: order within apparent chaos: Geol. Soc. America Abstr. Programs, v. 21, p. A206.

Lynch, D.J., Musselman, T.E., Gutmann, J.T., and Patchett, P.J., 1993, Isotopic evidence for the origin of Cenozoic volcanic rocks in the Pinacate volcanic field, northwestern Mexico: Lithos, v. 29, p. 295-302.

Gutmann, J.T., and Lutz, T.M., 1993, Middle Pleistocene shift in the pattern of vent distribution, Pinacate volcanic field, Sonora, Mexico: Geol. Soc. America Abstr. Programs, v. 25, p. A-267.

Lutz, T.M., and Gutmann, J.T., 1995, An improved method for determining and characterizing alignments of pointlike features and its implications for the Pinacate volcanic field, Sonora, Mexico: Journal of Geophysical Research, v. 100, p. 17659-17670.

Gutmann, J. T., and Prival, D. B., 1996, Strombolian and hydromagmatic volcanism in the Pinacate volcanic field: Geol. Soc. America Abstr. Programs, v. 28, p. A-503.

Bezy, J. V., Gutmann, J. T., and Haxel, G. B., 2000, A Guide to the Geology of Organ Pipe Cactus National Monument and the Pinacate Biosphere Reserve: Arizona Geological Survey, Down-to-Earth Series No.9, 63 pp.

Gutmann, J.T., Turrin, B.D., and Dohrenwend, J.C., 2000, Basaltic rocks from the Pinacate volcanic field yield notably young 40Ar/39Ar ages: Eos, Transactions, American Geophysical Union, v. 81, p. 33-37.

Gutmann, J.T., 2002,Strombolian and effusive activity as precursors to phreatomagmatism: eruptive sequence at maars of the Pinacate volcanic field, Sonora, Mexico: Journal of Volcanology and Geothermal Research, v. 113, p. 345-356.

Gutmann, J. T., and Turrin, B. D., 2006, The age of Crater Elegante, a maar in the Pinacate volcanic field, Sonora, Mexico:  Geol. Soc. America Abstr. Programs, v. 38, no. 6, p. 32.

Gutmann, J. T., 2007, Geologic studies in the Pinacate volcanic field: Journal of the Southwest, v. 49, no. 2, p. 189-243.

Turrin, B. D., Gutmann, J. T., and Swisher, C. C. III, 2008, A 13 ± 3 ka age determination of a tholeiite, Pinacate volcanic field, Mexico, and improved methods for 40Ar/39Ar dating of young basaltic rocks: Journal of Volcanology and Geothermal Research, v. 177, p.848-856.

Goss, A.R., Gutmann, J.T., Varekamp, J.C., and Kamenov, G., 2008, Pb isotopes and trace elements of the Pinacate volcanic field, northwestern Sonora, Mexico: a Basin and Range mini-plume near the EPR Spreading Center: Geol. Soc. America Abstr. Programs, v. 40, no. 6, p.530.

Goss, A.R., Gutmann, J.T., and Kamenov, G.D., 2009, A compositionally stratified mantle below the northern Mexican Basin and Range: trace elements and isotopic evidence from mantle xenoliths from the Pinacate volcanic field, Sonora, Mexico: Geol. Soc. America Abstr. Programs, v. 41, no. 7, p. 137

Gutmann, J.T., 2011, Estudios geológicos en el campo volcánico de El Pinacate: Calmus, T., ed., Publicaciones Ocasionales No. 5, Universidad Nacional Autónoma de México, Instituto de Geología, Estación Regional del Noroeste, 51 pp.


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