Fan-deltaic sequences in the Laborcita Formation, northern Sacramento Mountains, New Mexico, form a clastic wedge that prograded north and west. These Penn-Permian (Virgilian-Wolfcampian) deposits represent a facies tract of proximal to distal alluvial fan and fan-deltaic facies. Associated nearshore and shelf siliclastics are also developed.

Red bed conglomerates interpreted as braided and ephemeral fluvial channel fills are the most proximal deposits. These limestone cobble conglomerates crop out near the Fresnal Canyon fault and are syntectonic deposits. Northern quartzite cobble conglomerates are less proximal and form more continuous sheet-like units. These thick (10 m, 33 ft) and laterally extensive (6 km, 4 mi) conglomerates that contain trough cross-bedded coarse sand lenses associated with intrachannel bars are interpreted as midfan deposits.

Shales and thin (20-40 cm, 8-16 in.) progradational distal sands under conglomerates are highly variable in total thickness (20-60 m, 65-200 ft). The thin sandstones show evidence of marine processes and are interpreted as fan-deltaic foreset deposits. Gray limestone and chert conglomerates deposited directly on limestones are thin (0.5-2 m, 1.5-6.5 ft), deposited subaqueously, and exhibit reworking by marine processes.

Northern sands are disassociated with conglomerates. These green arkosic sands are relatively thick (3 m, 10 ft) and contain landward (east) accreting tangential foresets. Geometry, stratigraphic position, and minor upward coarsening indicate shelf-bar deposition.

Fan-delta source areas shifting during Laborcita deposition. Initial deposits were from the southeast and characterized by limestone/chert conglomerates. Later quartzite/rhyolite porphyry cobble conglomerates prograded from the east and northeast. Ultimately, alluvial fan red beds of the Abo Formation prograded over Laborcita fan-delta and shelf-bar deposits.

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