Established Series


The Tantalus series consists of moderately deep, well drained soils that formed in material weathered from volcanic ash and cinders. Tantalus soils are on uplands and have slopes of 8 to 70 percent. Mean annual rainfall is about 100 inches and mean annual temperature is about 70 degrees F.

TAXONOMIC CLASS: Medial over pumiceous or cindery, ferrihydritic, isothermic Typic Hapludands

TYPICAL PEDON: Tantalus silt loam - woodland. (Colors are for moist soil unless otherwise noted. All textures are "apparent field textures.")

A1--0 to 18 inches; very dark brown (10YR 2/2) silt loam, dark brown (10YR 3/3) dry; moderate very fine and fine subangular blocky structure; hard, friable, slightly sticky and slightly plastic; many fine roots; common very fine pores; common fine and very fine sharp cinders; neutral (pH 7.2); clear wavy boundary. (12 to 18 inches thick)

B2--18 to 29 inches; dark reddish brown (5YR 3/4) very fine sandy loam, reddish brown (5YR 4/4) dry; massive; soft, very friable, slightly sticky, slightly plastic and weakly smeary; many fine roots; few medium and coarse roots; many very fine and fine tubular pores; many very fine sharp cinders; neutral (pH 6.6); clear wavy boundary. (8 to 12 inches thick)

IIC--29 inches; black unweathered fine pebble-size cinders.

TYPE LOCATION: Honolulu County, Hawaii; Tantalus Mountain northeast of Punchbowl along Tantalus Drive; 3/4 mile northeast of Hawaii Board of Water Supply water tank; 50 feet west of road; 21 degrees 19' 48" north latitude and 157 degrees 49' 38" west longitude.

RANGE IN CHARACTERISTICS: The solum is 20 to 30 inches thick.

The A horizon has hue of 5YR through 10YR, and hue and chroma of 2 or 3. It is silt loam or silty clay loam.

The B horizon has hue of 5YR through 10YR and chroma of 2 through 4. It is very fine sandy loam, silt loam, or silty clay loam.

COMPETING SERIES: These are the Kaipoioi, Makiki and Manahaa series. Kaipoioi soils have chroma of 1 in the A horizon and mean annual soil temperature of less than 59 degrees F. Makiki soils have mean annual soil temperature of more than 72 degrees F., and a fine-loamy control section having mixed mineralogy. The Manahaa soils are 20 to 40 inches deep over hard rock and have mean annual soil temperature is less than 59 degrees F.

GEOGRAPHIC SETTING: The Tantalus soils are on strongly sloping to very steep dissected uplands, volcanic spurs and cinder cones at elevations from 100 to 2,200 feet. The soils formed in volcanic ash and cinders. Mean annual rainfall is 50 to 150 inches. Average January temperature is about 67 degrees F., average July temperature is about 73 degrees F., mean annual temperature is about 70 degrees F.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Makiki soils and miscellaneous areas such as Cinder land and Rough mountainous land.

DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; moderately rapid permeability.

USE AND VEGETATION: Used primarily for watershed, recreation and urban development. Vegetation is koa haole (Leucaena glauca), Formosa koa (Acacia confusa), swamp mahogany (Eucalyptus robusta), and kukui (Aleurites moluccana).

DISTRIBUTION AND EXTENT: Tantalus and Round Top mountain areas on the Island of Oahu, Hawaii. The soil is inextensive, with a total of about 2,100 acres.


SERIES ESTABLISHED: Soil Survey of the Territory of Hawaii, 1949.

OSED scanned by SSQA. Last revised by state on 5/78.

National Cooperative Soil Survey