The Honey Lake fault zone is one of four major, northwest-striking dextral faults that constitute the northern Walker Lane in northwestern Nevada and northeastern California. Global positioning system (GPS) geodetic data indicate that the northern Walker Lane accommodates ~10%–20% of the dextral motion between the North American and Pacific plates. Regional relations suggest that dextral movement in the Honey Lake area began ca. 6–3 Ma. Five 31.3–25.3 Ma ash-flow tuffs, totaling ~250 m in thickness, were distinguished in a paleovalley in the Black Mountain area of the Diamond Mountains, southwest of the Honey Lake fault. Four of these tuffs, totaling ~200 m in thickness, also occupy a paleovalley in the Fort Sage Mountains northeast of the fault. On the basis of the similar tuff sequences, we infer that the Diamond and Fort Sage Mountains contain offset segments of a once-continuous, westerly trending late Oligocene paleovalley. Paleomagnetic data from the 25.3 Ma Nine Hill Tuff indicate negligible vertical-axis rotation in the Diamond and Fort Sage Mountains. Correlation of the paleovalley segments in the Diamond and Fort Sage Mountains suggests 10–17 km of dextral displacement across the Honey Lake fault. About 10 km of offset is favored on the basis of constraints near the southeast end of the fault. The spread of possible offset values implies long-term slip rates of ~1.7–2.8 mm/yr for a 6 Ma initiation, and ~3.3–5.7 mm/yr for a 3 Ma initiation. These rates are comparable to slip rates inferred from Quaternary fault studies and GPS geodesy.

The Walker Lane, a zone of northwest-striking dextral faults east of the Sierra Nevada, accommodates 15%–25% of Pacific–North American plate motion. A distinctive feature of the Walker Lane is the coexistence of parallel dextral and normal faults, which either developed sequentially or are related by strain partitioning. In the northern Walker Lane, three en echelon dextral faults strike northwest parallel to relative motion between the Sierra Nevada and Great Basin. Each fault cuts major basins but is parallel to and 1–5 km basinward of range-front normal faults. Basins in this area have anomalous northwest trends, whereas basins and major normal faults in the adjoining Basin and Range province trend north to north-northeast. Major normal fault systems straddling the northern Walker Lane dip toward one another, thereby producing a structural low. Significant exhumation related to strike-slip faulting is restricted to one, more westerly striking, probably transpressional segment of one dextral fault. Geologic data suggest that northwest-striking range-front faults were active during a ca. 3 Ma episode of extension but have been inactive in the Quaternary. Strike-slip faulting probably started immediately after 3 Ma, either cutting or reactivating deeper parts of the northwest-striking range-front normal faults as dextral faults. North-striking normal faults are active and kinematically compatible with the northwest-striking dextral faults. The unusual northwest strike of normal faults in the northern Walker Lane may reflect reactivation of a major northwest-striking basement structure indicated by gravity data. Strain partitioning between parallel dextral and normal faults is unnecessary because the dextral faults parallel Sierra Nevada–Great Basin motion and can take up all required displacement. In contrast, Sierra Nevada–Great Basin motion in Owens Valley in the southern Walker Lane is strongly oblique to faults, so strain partitioning between parallel dextral and normal faults may be necessary.

Abstract Within the western Great Basin, a system of dextral strike-slip faults accommodates a significant fraction of the North American–Pacific plate motion. The northern Walker Lane in northwest Nevada and northeast California occupies the northern terminus of this fault system and is one of the youngest and least developed parts of the North American–Pacific transform plate boundary. Accordingly, the northern Walker Lane affords an opportunity to analyze the incipient development of a major strike-slip fault system. In northwest Nevada, the northern Walker Lane consists of a discrete ~50-km-wide belt of overlapping, curiously left-stepping dextral faults, whereas a much broader zone of disconnected, widely-spaced northwest-striking faults characterizes northeast California. The left steps accommodate little shortening and are not typical restraining bends. The left-stepping dextral faults may represent macroscopic Riedel shears developing above a nascent lithospheric-scale transform fault. Strands of the northern Walker Lane terminate in arrays of northerly striking normal faults in the northwestern Great Basin and along the eastern front of the Sierra Nevada. These relations suggest that dextral shear in the northern Walker Lane is transferred to ~NW-SE extension in the Great Basin. Offset segments of a west-trending Oligocene paleovalley suggest ~20–30 km of cumulative dextral slip across the northern Walker Lane. Strike-slip faulting began between 3 and 9 Ma, indicating a long-term slip rate of ~2–10 mm/yr, which is compatible with GPS geodetic observations of the current strain field .