LOCATION CERRO MARIQUITA PREstablished Series
TAXONOMIC CLASS: Clayey, mixed, active, isohyperthermic, shallow Typic Haplargids
TYPICAL PEDON: Cerro Mariquita gravelly clay loam--naturalized pastureland (Colors are for moist soil).
Ap--0 to 2 inches; very dark brown (7.5YR 2.5/2) gravelly clay loam; moderate fine and medium granular structure; soft, friable; slightly sticky, slightly plastic; many fine roots; common fine interstitial pores; about 25 percent, by volume, pebbles and 2 percent, by volume, cobbles; moderately alkaline; noneffervescent; abrupt smooth boundary. (2 to 8 inches thick)
Bt--2 to 13 inches; dark reddish brown (5YR 3/4) extremely paragravelly clay; massive parting to weak fine subangular blocky structure; soft, friable; sticky, slightly plastic; few fine roots; common fine interstitial pores; few faint clay films on ped faces and pore linings; about 45 percent, by volume, paragravels and 20 percent, by volume, paracobbles; slightly acid; noneffervescent; clear wavy boundary. (4 to 9 inches thick)
Cr--13 to 23 inches; highly fractured unconsolidated chert; abrupt wavy boundary. (4 to 10 inches thick)
R--23+ inches; hard consolidated chert bedrock.
TYPE LOCATION: Cabo Rojo, Puerto Rico. Sierra Bermeja Mountain Range; approximately 4.4 miles northwest of La Parguera community; about 0.6 mile northeast of Rancho Cabassa homestead on naturalized pastureland. USGS Parguera topographic quadrangle (1966); lat. 17 degrees 59 minutes 32 seconds N.; long. 67 degrees 06 minutes 45 seconds W.
RANGE IN CHARACTERISTICS: Depth to fractured unconsolidated rock ranges from 11 to 18 inches. Depth to hard consolidated chert bedrock ranges from 15 to 25 inches. Reaction ranges from slightly acid to moderately alkaline throughout.
The A or Ap horizon has hue of 5YR to 10YR, value of 2.5 to 4, and chroma of 2 to 4. Content of pebbles and cobbles ranges from 20 to 55 percent, by volume. Texture is clay loam or clay in the fine-earth fraction.
The Bt horizon has hue of 2.5YR or 5YR, value of 3 to 6, and chroma of 4 to 8. Content of paragravels and paracobbles range from 25 to 65 percent, by volume. Texture is clay in the fine-earth fraction.
The BC horizon, where present, has hue of 5YR or 7.5YR, value of 4 to 6, and chroma of 4 to 8. Texture is clay loam or their gravelly analogs.
The Cr horizon is composed of unconsolidated basalt, chert or rhyolite. It can be excavated with difficulty with hand tools, and is rippable by mechanical equipment.
The R layer is composed of hard fractured basalt, chert, or rhyolite bedrock.
COMPETING SERIES: There are no known series in the same family.
GEOGRAPHIC SETTING: The Cerro Mariquita soils are on side slopes and summits of hills and mountains on the Semiarid Mountains and Valleys MLRA. Slopes range from 12 to 60 percent. They formed in residuum and colluvium material weathered from basalt, chert and rhyolite. The climate is semiarid tropical. The average annual precipitation ranges from 28 to 36 inches and the average annual temperature ranges from 78 to 82 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bermeja (T), Llanos Costa (T) and Maguayo series. Bermeja (T) soils are on similar positions but do not have an argillic horizon. Llanos Costa (T) soils are on alluvial fans, are very deep and have clayey-skeletal subsoil. Maguayo soils are on alluvial fans, are very deep and have clayey subsoils. Cerro Mariquita soil formed in the Mariquita Chert Formation (KJm).
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Most areas of Cerro Mariquita soils are on naturalized pastureland and wildlife habitat. The vegetation consists of xerophytic grasses, shrubs and trees.
DISTRIBUTION AND EXTENT: Side slopes and summits of hills and mountains of the Semiarid Mountains and Valleys MLRA. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Raleigh, North Carolina.
SERIES ESTABLISHED: Cabo Rojo Municipality, Puerto Rico; 2007. The name is from Cerro Mariquita Peak, nearby where it was originally recognized.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Ochric epipedon - the zone from 0 to 2 inches (Ap horizon).
Argillic horizon - the zone from 2 to 13 inches (Bt horizon).
Paralithic contact - the contact at 13 inches (Cr horizon).
Lithic contact - the contact at 23 inches (R horizon).
These soils were formerly included in the Guayama series. A soil moisture study performed in the San German Area Soil Survey Update recognizes the Aridic Soil Moisture Regime in southern Puerto Rico.
Cerro Mariquita soils are in MLRA 271.