INFANTE, Formation

UPPER CRETACEOUS (Turonian-Coniacian ?)

State of Guárico, Venezuela

Authors of name: J. M. Patterson and J.G. Wilson, 1953.

Original reference: J. M. Patterson and J. G. Wilson, 1953, p. 2714.

Original description: ibid.

The name Infante was applied by Patterson and Wilson (1953) to the limestone body used as a principal reflecting horizon in seismic mapping in the Las Mercedes area, state of Guárico. It was formerly called the "N" limestone, the term being derived from a letter system of designation used for many years. The type section for the Infante ("N") limestone is the well Guayabo-2 in which the limestone was first encountered (top at 5400'), and in which the letter nomenclature was first used. The name Infante comes from the district of Infante, state of Guárico, where in the northern part of the district the limestone is developed in the subsurface. It is not known to crop out.

The Infante limestone is part of the Temblador group of Patterson and Wilson (1953, p. 2711-14), and as the limestone is a mappable unit, it was raised to formation rank. The limestone iB overlain and underlain respectively by the Guavinita and La Cruz formations also of the Temblador group. According to Patterson and Wilson (1953, p. 2726), the Infante formation is probably equivalent to the La Luna formation, which in turn is Turonian and possibly Coniacian in age (Mencher et al., 1953, Chart I).

Lithologically, the formation is a dense, grey to brown, locally glauconitic, compact, fossiliferous limestone, and locally exhibits replacement by silica, as much as 80 % in the upper part.

The thickness varies from O' to 60' in northern Guárico.

In south and southwest Guárico, the limestone is represented by contemporaneous sands undifferentiated from overlying and underlying sediments. To the west the formation is truncated by Tertiary overlap.

S. J. Brown