Geology of portions of the Humphreys and Sylmar quadrangles
The portions of the Sylmar and Humphreys Quadrangles studied consist of Jurassic? "basement complex" and sediments of Pliocene age and younger. These are brought together along the San Gabriel fault. The Tertiary sediments comprise the Mint Canyon formation, the Modelo formation, the...
| Summary: | The portions of the Sylmar and Humphreys Quadrangles
studied consist of Jurassic? "basement complex" and sediments of Pliocene age and younger. These are brought
together along the San Gabriel fault. The Tertiary sediments comprise the Mint Canyon formation, the Modelo
formation, the Pico formation, the Saugus formation, and
Quaternary terrace and alluvial material. These are
listed in order of decreasing age. All the contacts between the various sedimentary formations are unconformable.
The Miooene formations are highly folded and faulted, and a large vertical fault displaces upper miocene beds. The Pliocene and younger formations also are folded, but
to only a minor degree.
The abundance of shale in the Tertiary section makes the region one of numerous landslides. In addition, unusual erosive action and succession of units has resulted
in the carving out of a small-scale natural bridge.
There is no production of economic materials from the area at the present time, but the possibilities of petroleum development are now being given serious consideration.
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