Panamá Fm

The type area is with the exposures along the waterfront in the city of Panama, Panama Province.

Synonym: Panama Fm ;

• Panamá tuff (Wilmarth (1938)); Pedro Miguel Agglomerate Member of the Panamá Fm (which has been renamed as Pedro Miguel Fm (see description))
• "Panamá Fm" to include the analogous deposits of Barbacoas, San Pablo, and Miraflores Hill (1898, p.206)

Estimated thickness at least 300 meters.

References:

• Hill (1898)
• Hershey (1901) (Figure 052); Wilmarth (1938); Olsson (1942b)
• Woodring & Thompson (1949). Referred to as Panamá tuff.
• Woodring (1957). Formation proper includes tuff, tuffaceous sandstone, tuffaceous siltstone, and agglomerate. They evidently represent nonmarine, essentially fine-grained tuff and tuffaceous strata that interfinger with and overlie La Boca Fm (La Boca marine Member) and Pedro Miguel Fm (Pedro Miguel agglomerate Member). Estimated thickness at least 300 meters. Geologic map suggests that formation proper overlaps part of Caimito Fm, but that relation needs confirmation. La Boca marine Member apparently overlaps Cucaracha Fm and Culebra Fm. La Boca Member and presumably entire Panamá Fm is not much younger than the Culebra Fm and like the Culebra is considered early Miocene. Entire succession above Las Cascadas agglomerate (Culebra Fm, Cucaracha Fm, and Panamá Fm) is believed to represent early half of early Miocene time; that is, the disputed Oligocene or Miocene.
• Woodring (1960). The Panamá Fm is made up of acidic tuff of varying grain size, agglomerate, and tuffaceous mudstone and sandstone. The outcrop area extends from the Pacific terminus of the Canal northeastward beyond the city of Panama. The thickness is undetermined. The lower part of the pyroclastics is inferred to be the equivalent of the La Boca marine Member. The designation Panamá tuff has been used, but Panamá Fm is preferable.
• Keroher et al. (1966); Stewart, Stewart, Woodring (1980); Woodring WP (1982)
• Woodring (1970). The Panamá Fm is redefined to include strata formerly assigned not only to the Panama itself, but also to the Bohío Fm and Caimito Fm, and the Pedro Miguel Fm (Pedro Miguel agglomerate). As redefined the Panama consists chiefly of agglomerate and tuff, extending from the Miraflores Lake area to Panama City, and also northeastward across the continental divide and eastward in the Pacific coastal area to and beyond the limit of plate 1. The formation also includes tuffaceous sandstone, tuffaceous siltstone, lenses of stream deposits, and lenses of marine limestone.
• Stewart RH, Stewart JL, Woodring WP (1980)’s map describes the Panamá Fm as early to late Oligocene, principally an agglomerate, generally andesitic in fine-grained tuff. Includes stream-deposited conglomerate. The marine facies of the Panamá Fm is also early to late Oligocene. Tuffaceous sandstone, tuffaceous siltstone, algal and foraminiferal limestone. Sandy siltstone in basal part of formation in Quebrancha syncline.
• Woodring WP (1982) reconfirms the age of the formation as late to early Oligocene.