Meyer Lake
Meyer Lake is a shallow pond covering 8.4 acres on the northern part of the island of Molokaʻi, Hawaii. It is primarily fed by surface runoff and submerged springs and is located south of Kalaupapa at an altitude of 2,000 ft. The lake is named after Rudolph Wilhelm Meyer.
The lake occupies a shallow depression on the andesite lava of the upper member of the East Molokai Volcano, at the southeastern foot of Puʻu ʻŌlelo cinder cone. It is a perched pond, held at that level by impermeable underlying andesite and weathered soils. It takes runoff water from a surrounding catchment of approximately 100 acres. A small dam about 6 ft high has slightly increased the pond’s capacity. The depth varies seasonally but has been recorded as being no greater than 5 ft. The pond area ranges from about 8.4 to 10.3 acres depending on the water stage of Molokaʻi.
Geology and soil
The soils surrounding Meyer Lake are highly weathered tropical soils with a high content of iron oxide and humic substances characterized by a lack of distinct soil horizons. The soil is classified as belonging to the ferruginous humic latosol group and has accumulated iron and titanium oxides near the surface, forming titaniferous‑ferruginous laterites. These soils typically form in regions with alternating wet and dry seasons and often show concentrations of iron and titanium oxides, sometimes forming concretions, in the surface horizons. The process of laterization occurs when silica is leached out while iron and aluminum are concentrated.Between 1952–1953, shrubs such as guava were cleared for pasture improvement, exposing areas of extremely high titanium content. Indurate, dehydrated soil areas are grayish‑purple in color, in contrast to the reddish-brown surrounding soils. These areas contain numerous magnetic ferruginous concretions, indicating movement and redeposition of iron by percolating water. Erosion also transports soil aggregates to the foot of nearby slopes.
Chemical analyses have measured high iron oxide and titanium oxide in the concretions. Along the shoreline these have lower titanium content but high iron oxide, reflecting sediment sorting and accumulation by wave action. Studies of molecular ratios suggest that titanium oxide increases with dehydration of the soil, while ferric oxide accumulates in the hardened concretions.