Sandstone of Hunter Creek
Sandstone of Hunter Creek
Quaternary to Miocene
Consists of a thick, conformable, and broadly fining-upward sequence of coarse conglomerate to diatomite, with sparse interbedded lava flows and pyroclastic fall deposits, cropping out along the margins of the Verdi basin around and west of Reno, Nevada, and to the north in Lemmon Valley.
Basal section consists of coarse (cobble to boulder) conglomerate and debris flow deposits (including lahars) interbedded with lesser sandstone and variably diatomaceous siltstone (Trexler and others, 2012). Clasts are predominantly volcanic rock types, with lesser metamorphic and locally substantial granitoid clasts, all commonly subrounded to well rounded (Bell and Garside, 1987; Bingler, 1965; Trexler and others, 2012). Some debris flow deposits contain prismatically jointed blocks indicating emplacement as hot syn-eruptive lahars (Trexler and others, 2012). Basaltic andesite lavas are present only in the basal section and have Ar-Ar dates of ~10.1 to ~10.4 Ma (Henry and Perkins, 2001; Trexler and others, 2012).
The middle section consists of pebbly sandstone, siltstone, and muddy diatomite; cross-lamination and channel structures are common, as are rooted horizons (Trexler and others, 2012). Minor interbedded pyroclastic fall deposits and volcanic clast-dominated conglomerates are also present. Hosts late Clarendonian to Hemphillian terrestrial vertebrates, including gomphothere, camel, and horse species (Kelly, 2001; Kelly and Secord, 2009). Also hosts the “Verdi flora” which consists almost entirely of riparian and lake-border plant species (Trexler and others, 2012). 
The upper section consists of diatomite, variably diatomaceous siltstone, and sandstone with minor interbedded pyroclastic fall deposits (Trexler and others, 2012) and stratigraphically minor but areally extensive dune deposits (Bingler, 1965). Pyroclastic fall beds contain plagioclase grains as young as 2.67 ± 0.42 Ma (Trexler and others, 2012). Also hosts assemblage of vertebrate fossils indicating age no older than 2.6 Ma, and possibly as young as 1.5 Ma (Kelly, 2001; Kelly and Secord, 2009). 
Throughout the unit, material is >80% volcanic (Trexler and others, 2012; Queen, 2008). Deposited in predominantly fluvial to deltaic to lacustrine environments within a closed, extensional basin (Ramelli and others, 2011; Trexler and others, 2012). Present as east-plunging syncline with thickness up to 2.6 km and truncated on east, in subsurface, by normal down-west fault (Cashman and others, 2012; Trexler and others, 2000, 2012).
Informally named the sandstone of Hunter Creek by Bingler (1965), who applied the name only to fill strata in a part of the Reno-Verdi basin. Here we generalize to include units to the north, in Lemmon Valley, which were deposited in a different basin from those of the sandstone of Hunter Creek proper and differ stratigraphically, but which are otherwise similar in age, composition, and depositional environment.