Salt Dome Extravaganza

Senior Research Scientist Martin P. A. Jackson recently returned from a month of travel, research, and adventure in Sweden and Iran under the auspices of the Applied Geodynamics Laboratory. Martin was away from January 14 through February 15, 2004.

The southern face of the 1-km-high summit dome of Kuh-e-Namak (Dashti). Tertiary country rocks flank several retreating salt glaciers issuing southwards from the summit. Neoproterozoic-Cambrian Hormuz salt basin, Zagros Mountains, southwestern Iran.
Uppsala (Sweden)
Three days were spent in Uppsala visiting the Hans Ramberg Tectonic Laboratory at Uppsala University as a guest of Chris and Rosemary Talbot. Martin gave lecture to faculty and graduate students on "A New Look at Salt Tectonics, Tectonostratigraphy, and Differential Uplift in the Kwanza Basin, Angola."
Iran
Martin visited Iran with a group of European specialists in structural geology and tectonics as invited guests of the Geological Survey of Iran (GSI). GSI very generously logistically supported the group during their time in Iran. A Fellowship from the Jackson School of Geosciences provided funding for the flights to Tehran.  European specialists included Professor Christopher Talbot (Uppsala University), Professor Hemin Koyi (Uppsala University), Dr. John Cosgrove (Imperial College, London), and Dr. Jean Letouzey (Institut Français du Pétrole, Paris).               Click on all images to enlarge.
In a mosque at Semnan, in the Alborz foothills, northern Iran.
Part of the field party in front of Damavand volcano, the highest point in Iran (18,602 feet, 5670 m). Alborz Mountains, northern Iran. From left to right: Mr. Momeni, Pedram Aftabi, John Cosgrove, Chris Talbot, Abbas Bahroudi, Hemin Koyi, Abbas Ghassemi, Martin Jackson.  
Salt Tectonics Field Trip
A 3-week field trip was led by Chris Talbot, a veteran of 10 field seasons working on Iranian salt tectonics in collaboration with GSI colleagues.
View down the length of Qom Kuh, an actively flowing salt glacier near Qom, the religious capital of Iran. Most of the salt is covered by gypsite, a residual soil left by salt dissolution. Dark-green hills in the middle distance are Eocene igneous blocks in the terminal moraine. Qom Tertiary salt basin, central Iran.
Iran contains by far the largest concentration of emergent salt diapirs on Earth. About 160 emergent diapirs are known. These offer an outstanding opportunity to examine at close quarters salt domes and allochthonous salt sheets that elsewhere in the world are buried and only accessible by drilling or geophysical probing. During this three-week field trip, the group visited salt structures in four salt basins: Qom (Tertiary), Zagros (Eo-Cambrian), Great Kavir (Tertiary), and Garmsar (Tertiary). The party traversed into 12 salt diapirs and allochthonous complexes and sighted 23 additional salt diapirs from varying distances.
 
 
Dome 27 rises above playa mudflats. In the center of the image, strata curve in the upturned collar of Upper Red Formation country rocks. At right center, gyprock ridges define a recumbent fold. Great Kavir Tertiary salt basin, central Iran. Refolded fold in quarried rock salt, forming part of a pile of evaporite nappes; 10-cm scale. Garmsar Tertiary salt basin, northern Iran.
Snow-capped anticlines in the Zagros Mountains detach at several décollement levels, including the Hormuz and Gachsaran evaporites.
   
Dissolution of salt forms sharp pinnacles and ridges on a centimeter scale. Layering dips gently to the left. Neoproterozoic-Cambrian Hormuz salt basin, Zagros Mountains, southwestern Iran. Abbas Ghassemi in the erosional wonderland of Kuh-e-Namak (Dashti). In the far distance is the summit dome. All other rocks form part of the northern salt glacier fed by the salt fountain. Neoproterozoic-Cambrian Hormuz salt basin, Zagros Mountains, southwestern Iran.
Chris Talbot, Jean Letouzey, and Hemin Koyi descend the southern salt glacier of Kuh-e-Namak (Dashti), which extends into the distance. On the right are Tertiary country rocks. Neoproterozoic-Cambrian Hormuz salt basin, Zagros Mountains, southwestern Iran.

The trip covered a wide variety of salt structures, which ranged from those that have been extensively studied (such as Kuh-e-Namak (Dashti) and Qom Kuh), those that have been partly investigated (such as the Garmsar Plateau), to salt domes entirely lacking modern field work (such as those in the Great Kavir).
All photographs by Martin Jackson