Gumdrop Seamount is a small seamount

Seamount

A seamount is a mountain rising from the ocean seafloor that does not reach to the water's surface , and thus is not an island. These are typically formed from extinct volcanoes, that rise abruptly and are usually found rising from a seafloor of depth. They are defined by oceanographers as...

 (underwater volcano) located on the flank of Pioneer Seamount, off the coast of Central California

Central California

Central California, sometimes referenced as Mid-State, is an area of California south of the San Francisco Bay Area and north of Southern California...

. It is the northern-most of the related seamounts in the region, which includes Davidson

Davidson Seamount

Davidson Seamount is a seamount located off the coast of Central California, southwest of Monterey and west of San Simeon. At long and wide, it is one of the largest known seamounts in the world. From base to crest, the seamount is tall, yet its summit is still below the sea surface...

, Guide

Guide Seamount

Guide Seamount is a seamount in the eastern Pacific Ocean, about 16.6±0.5 million years old. It is similar in shape and orientation to the nearby Davidson, Pioneer, Rodriguez, and Gumdrop seamounts. It is named for the U.S. National Geodetic Survey survey ship the US&GS Guide.Guide Seamount is...

, Pioneer

Pioneer Seamount

Pioneer Seamount is an undersea mountain, or seamount, in the Pacific Ocean off the coast of central California.-Location:Pioneer Seamount is located at 37° 21.1' North Latitude, 123° 26.1' West Longitude, at the base of the continental slope of North America about 95 kilometers off the coast just...

, and Rodriguez

Rodriguez Seamount

Rodriguez Seamount is a seamount and guyot located about off the coast of Central California. It is structurally similar to the nearby Guide, Pioneer, Gumdrop, and Davidson seamounts, all located roughly between 37.5° and 34.0° degrees of latitude. This group of seamounts is morphologically...

 seamounts. It is defined by a series of aligned cones separated by troughs filled with sediments, the majority of which are poorly defined. The largest cone rises to within 1207 m (3,960 ft) of sea level

Sea level

Mean sea level is a measure of the average height of the ocean's surface ; used as a standard in reckoning land elevation...

. It is estimated to have a volume of about 100 km³ (24 cu mi), but the poorly defined base hinders observations of its size. Samples recovered from Gumdrop are highly vesicular

Vesicular texture

Vesicular texture is a volcanic rock texture characterised by a rock being pitted with many cavities at its surface and inside. The texture is often found in extrusive aphanitic, or glassy, igneous rock...

 in origin, and include alkalic basalt

Basalt

Basalt is a common extrusive volcanic rock. It is usually grey to black and fine-grained due to rapid cooling of lava at the surface of a planet. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered basalt is black or grey...

, hawaiite

Hawaiite

Hawaiite is an olivine basalt with intermediate composition between alkali olivine and mugearite. It was first described at the island of Hawaii. In gemology, hawaiite is a colloquial term for Hawaii-originated peridot,which is gem-quality olivine mineral....

, and mugearite

Mugearite

Mugearite is a type of orthoclase-bearing basalt, comprising olivine, apatite, and opaque oxides. The main feldspar in mugearite is oligoclase....

; however, their ages have yet to be determined.