Ainoni volcanics. Basalt and cinders. Nepheline basalt lava flow 0.75 mi long and 0.5 mi wide; lies on northeast side of Koolau Range about 8 mi northwest of Makapuu Head, and 1.5 mi southwest of Olomana Peak on Maunawili Ranch, Island of Oahu. The basalt forms massive walls along Ainoni and Maunawili Streams and generally shows columnar jointing. Included in middle part of Honolulu volcanic series [q.v.]. Unconformably overlies alluvium. Contains inclusions of Koolau dike complex. Terraces indicate eruption probably took place during Waipio stand of sea, perhaps simultaneously with Maunawili volcanics. Age is middle(?) and late Pleistocene.
[Type locality not designated.] Named from Ainoni Spring, which issues from east margin of lava flow, 1.5 mi southwest of Olomana Peak on Maunawili Ranch, [Koolaupoko district, approx. Lat. 21 deg. 20 min. 54 sec., N., Long. 157 deg. 45 min. 57 sec. W., Koko Head 7.5-min quadrangle, Honolulu Co.], Island of Oahu, HI. Lava flow is 0.75 mi long and 0.5 mi wide on northeast side of Koolau Range, about 8 mi northwest of Makapuu Head, Island of Oahu, HI.
[Additional locality information from USGS GNIS database and ACME Mapper 2.0, accessed November 2, 2011. Hawaiian spelling: 'Ainoni Spring (U.S. Board on Geographic Names, 2000).]

Source: US geologic names lexicon (USGS Bull. 896, p. 19); supplemental information from GNU records (USGS DDS-6; Menlo GNULEX).

Pg. 76. Ainoni volcanics in Honolulu volcanic series. Nepheline basalt flow about 100 feet thick, and associated cinder cone. Distribution noted. Underlying alluvium connects with deposits believed to have formed during plus 95-foot (Kaena) stand of sea. Eruption probably occurred during minus 60-foot (Waipio) stand, perhaps simultaneously with Maunawili volcanics. Age is considered late Pleistocene.

Source: US geologic names lexicon (USGS Bull. 1200, p. 31); GNU records (USGS DDS-6; Menlo GNULEX).

K-Ar age on basalt from Ainoni vent gave 2.01 +/-0.05 Ma.

Source: GNU records (USGS DDS-6; Menlo GNULEX).

Ainoni Volcanics (Stearns, IN Stearns and Vaksvik, 1935) abandoned as formally named unit and called Ainoni flow (and associated cone), informal unit of Honolulu Volcanics.

Source: GNU records (USGS DDS-6; Menlo GNULEX).