REVISITING ALKALI LAKE, OREGON MAGADIITE: A REANALYSIS OF LAKE SHORE SEDIMENTS

In 1969, fresh magadiite deposits were found precipitating in the strata surrounding Alkali Lake, Oregon. In 2023 fresh surface samples from this area were collected and analyzed using X-ray diffraction (XRD). XRD showed the presence of magadiite and quartz within the same sample which corresponds to visual observations. The samples found in Alkali Lake were solidified and showed evidence of the non-biogenic formation of surface chert from precipitated magadiite in the span of 54 years or less. This process was previously thought to take up to 20,000 years based on earlier research done in East Africa (Hay, 1968). Smear slides of samples showed relict lepispheres and quartz crystals that are likely remnants of magadiite structures. It is hypothesized that as sodium and water leach out of magadiite, it slowly solidifies into micro-quartz crystals and forms into chert at a near 1:1 ratio. The samples collected in Alkali Lake, Oregon provide significant evidence of chert forming in the surface/near surface environment, over a span of 54 years or less.