Lebu Group
Chilean geologic formation
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Lebu Group is stratigraphic unit of Arauco Basin in south-central Chile. The group consists of a sequence of four formations, of both marine and nonmarine origin, deposited between the Early Paleocene and Middle Eocene.[1]
Sub-unitsMillongue Formation
Trihueco Formation
Boca Lebu Formation
Curanilahue Formation
Trihueco Formation
Boca Lebu Formation
Curanilahue Formation
UnderliesRanquil Formation
OverliesQuiriquina Formation
| Lebu Group | |
|---|---|
| Stratigraphic range: Paleocene–Eocene | |
| Type | Stratigraphic group |
| Sub-units | Millongue Formation Trihueco Formation Boca Lebu Formation Curanilahue Formation |
| Underlies | Ranquil Formation |
| Overlies | Quiriquina Formation |
| Lithology | |
| Primary | Shale, sandstone, siltstone, mudstone |
| Other | Coal |
| Location | |
| Coordinates | 37.6°S 73.7°W |
| Approximate paleocoordinates | 40.1°S 64.2°W |
| Region | Bío Bío Region |
| Country | Chile |
| Extent | Arauco Basin |
| Type section | |
| Named for | Lebu |
  Lebu Group (Chile) | |
Description
The group is made up of four formations, from youngest to oldest these are: Millongue Formation,[note 1] Trihueco Formation, Boca Lebu Formation and Curanilahue Formation.[1]
The Eocene Millongue Formation is composed of shale and siltstone of both marine and continental origin. Its top is marked by an unconformity, the so-called “main unconformity” of Arauco Basin, which is thought to have formed by erosion during a period of tectonic inversion.[1][3]