Nancy Point Fm

There are no exposures between the stratotypes of the Nancy Point and the Tobabe Sandstone Fm along the north coast of the Valiente Peninsula. Assuming a constant dip (the type Tobabe Fm and Nancy Point Fm have the same strike and dip), 400 m of section is not exposed. Much of this missing interval is exposed on the southern coast of the Valiente Peninsula between Warrie Point and the southern headland of the small peninsula of Toro Point (Figure 043; Figure 042), and is diagrammed in Section 15 of Coates (1999). Lithologically it appears to be more typical of the Nancy Point Fm.

[Figure 1. Bocas del Toro archipelago, NW Panama with map of the western & central portion together with the geological maps of Isla Colon, Isla Bastimentos, Punta Valiente (Klaus et al. (2012)) and Popa Island (Coates et al. (2005)). Section (b-b’) over Popa Island shows the Valiente Fm where it is unconformably overlain by the Pliocene Cayo Agua Fm. On Popa Island, only the v1 basalt flow facies and the v2 coarse volcaniclastic facies (see Figure 043) (not associated with reef lenses) are present, with thin layers of low rank coal, an example of which is exposed along the coast immediately north of Punta Laurel. A prominent basalt dike is exposed at the tip of the Punta Laurel where it cuts the Valiente Fm.]

Synonym:

The transition from Tobabe Fm to Nancy Point Fm deposits is best seen on Toro Cay (Figure 2), where dark blue-gray, silty sandstone, typical of the Nancy Point Fm, contains occasional, clearly defined 50-cm-thick thalassinoid burrow systems and extremely abundant and diverse mollusks. It overlies coarse, channeled Tobabe Sandstone Fm with only a 10m gap. The transition from the Tobabe Sandstone Fm to the Nancy Point Fm thus appears to be conformable and to involve relatively rapid deepening from nearshore to upper slope facies.

Thickness: 500 m

The stratigraphic order of the Tobabe Sandstone Fm, Nancy Point Fm and Shark Hole Fm (three of the five formations which make up the Bocas Del Toro Gr) has been determined by physical superposition. The two remaining formations of the Bocas Del Toro Gr (Escudo De Veraguas Fm and Cayo Agua Fm) as well as the younger Pleistocene Swan Cay Fm are known only on islands and their position relative to the other units has been determined by bio-stratigraphic evidence (Figure 3).

[Figure 2. Coates et al. (2003 & 2005)’s description of the geological map and cross sections (A-A’ and B-B’) of the Valiente Peninsula (Punta Valiente) showing the distribution of the Punta Alegre Fm and Valiente Fm and the Bocas Del Toro Gr. The five lithofacies of the Valiente Fm are indicated by separate colors and numbers on the key (upper right) as follows; v1) basalt lava and flow breccia facies; v2) coarse volcaniclastic facies; v3) pyroclastic facies; v4) coral reef facies; v5) marine debris flow and turbidite facies.]

[Figure 3. Correlation of measured sections in the Bocas del Toro Basin. Coates (1999). (Reproduced with permission of the Paleontological Research Institution, Ithaca, New York)]

References: Collins et al. (1999a & 1999b); Coates (1999); Coates et al. (2005); Todd & Collins (2005); Beu (2010); Landau et al. (2012a, 2012b); Schwarzhans et al. (2013); https://en.wikipedia.org/wiki/Nancy_Point_Formation