MIRADOR, Formation

State of Zulia, Venezuela

Author of name: F. de Loys, 1918 (private report).

Original reference: A. H. Garner, 1926, p. 680.

Original description: ibid. Garner (1926, p. 680) applied the name Mirador sandstone to a prominent sandstone which forms the Cerro El Mirador in the southwestern part of the Colón district, state of Zulia.

Notestein et al. (1944, p. 1194) give the following lithological description: the Mirador formation is predominantly composed of sandstones. These are pale buff to white, characteristically clean, massive, moderately hard to friable, fine to coarse-grained, and in part conglomeratic. It contains some thin beds of gray and brownish-gray micaceous shale. An interval of shale and sandy shale with a little sandstone commonly occurs 40 to 75 meters below the top of the formation and ranges from 10 to 70 meters in thickness. The sandstones in the lower part of the formation tend to be more thinly bedded and less clean than the bulk of the formation. The Mirador is topographically prominent, forming escarpments, ridges, cliffs, and prominent dip slopes. Thickness 160-400 meters in surface sections. No fossils found.

The shale break in the Mirador formation which, according to Liddle (1946, p. 397), contains locally coal seams is referred to, by Shell geologists (Staff of Caribbean Petroleum Co., 1948, p. 611) as Intermediate Shale, situated between the Upper Sandstone and the Lower Sandstone. The Mirador lies directly on the Third Coal according to some authors with, and according to others without unconformity. It is probably unconformably overlain by the Sandy Shale formation. The age according to Liddle (1946, p. 397) is believed to be Oligocene, but Kehrer in Liddle (1946, p. 397) considers the Mirador to be doubtless Eocene. According to Notestein et al. (1944, p. 1194) the Mirador is middle or upper Eocene in age and Sutton (1946, p. 1669) puts the Mirador in the upper Eocene.

González de Juana (1951, p. 268) correlates the Mirador with the Misoa formation and the age is believed to be upper middle Eocene. Accor ding to the same author the La Sierra sandstone west of Machiques is the lateral equivalent of the Mirador. The Mirador crops out in the State of Táchira, in the Colón district of the Zulia State and in adjacent parts in Colombia.

W. A. Mohler