Peter J. Unmack photo

Peter J. Unmack photo

Habitat of the previous stromatalite
Peter J. Unmack photo

Peter J. Unmack photo

Cyclotella sp
Diatom: Microscope photo at 1000X magnification. Collected September, 1979 in Pozo Churince
Barbara Winsborough photo

One season's accumulation of diatoms from a stream bed at Garabatal. Photo taken in Oct. 1986.
Barbara Winsborough photo

Biddulphia laevis
Diatom: Light microscope photo from Canal Principal de la Becerra, magnification is 1000X. Collected in 1980.
Barbara Winsborough photo

View of the diatom assemblage living in the mud of Laguna Churince. Photo taken at 500X magnification. Sample collected in 1980.
Barbara Winsborough photo

Scanning electron microscope image of dead fragment of the macroalga Chara sp. The stem is coated with diatoms Collected at Garabatal, Oct. 1986.
Barbara Winsborough photo

Navicula brasiliensis
Light microscope photo of diatom from Pozo Escobedo, magnification is 1000X.
Barbara Winsborough photo

Oncoid from Laguna el Mojarral. Left side internal view showing laminated growth pattern caused by seasonal algal growth on surface. Right side shows typical terraced projections on surface of this calcium carbonate structure. Scale in cm, Photo taken May 1984.
Barbara Winsborough photo

SEM microscope photo of two species of protozoans with cell walls made of calcite plates. Sample from Pozo Azul, southern part of Cuatrociénegas Basin. Photo taken Nov. 1986.
Barbara Winsborough photo

View of Laguna Garabatal showing ancient stromatolites along west side. Photo taken 1980.
Barbara Winsborough photo

View of shallow ledge in Pozo Azul. Note small stromatolites on ledge. Depth of pozo is 10m. Photo taken in 1983.
Barbara Winsborough photo

Low-magnification microscopic view of live diatom community growing on stromatolites (estromatolitos) at Laguna Garabatal. Individual Diatom cells are located at the ends of long stalks that are attached to the rock. Photo taken Nov. 1986.
Barbara Winsborough photo

Top view of Pozo Azul stromatolites (estromatolitos), showing typical growth pattern. Photo taken Nov. 1986.
Barbara Winsborough photo

Side view of Pozo Azul stromatolites showing variations in color due to presence of different algae and bacteria at different distances inward from the surface of the structure. Photo taken Nov. 1986.
Barbara Winsborough photo

Jagged iron- and manganese-rich surface of underwater cave wall in Laguna el Mojarral. See description below of thin section also. Sharp outline is due to high current flow. Photo taken March 1987.
Barbara Winsborough photo

Hard, lithified carbonate stromatolites in Laguna Garabatal photographed during the dry season.
Barbara Winsborough photo

Petrographic thin section of laminated iron- and manganese-rich deposit on the wall of the cave in Laguna el Mojarral. Photo taken at 100X magnification. Sept. 1987.
Barbara Winsborough photo

Petrographic thin section of laminated iron- and manganese-rich deposit on the wall of the cave in Laguna el Mojarral. Photo taken at 100X magnification. Sept. 1987.
Barbara Winsborough photo

Photo of wall of clinic in Cuatro Ciénegas showing ancient lake stromatolites preserved in stone, that were quarried in the basin.
Barbara Winsborough photo

Underwater photo of delicate stromatolites in shallow part of Pozo Azul, forming at a depth of 1/2 meter. Note damage to several stromatolites from being stepped on. Photo taken Nov. 1986.
Barbara Winsborough photo

Broken stromatolites from Pozo Azul. Photo taken Nov. 1986.
Barbara Winsborough photo

Broken stromatolites from Pozo Azul. Photo taken Nov. 1986.
Barbara Winsborough photo