Geological and Environmental History of Parker's Preserve
The preserve is geographically located in an area commonly referred to as "The Blackland Prairie". At one point in time all of this area was part of the sea. Geologically, all of these prairies are relatively new having been formed as the sea retreated with resultant trapping of minerals and sea life. The soils that developed are a result of the deposited sea life and salts formed after evaporation. As the above was taking place, migratory birds and animals as well as wind currents were introducing various plants, microorganism and other organic materials. Rainfall, temperature changes and natural erosion also contributed to the development of the existing soil environment.
Although this area lies in prairie country, the soil type (Houston clay) which encompasses the preserve is not a true prairie one, but rather a "Rendzina" type.
Rendzina soils are of a prairie type having gray or black surface layers overlaying soft, light-gray or white highly calcareous material. These soils developed from marl, chalk, and soft limestone and may be relatively immature. They have accumulated large amounts of organic matter, which give them the dark surface layer color.
The Houston Clay soil developed predominately from marl and chalk. It has the dark color and high organic matter content that characterizes prairie soils but is calcareous throughout all layers. The development of a normal prairie-soil profile has been retarded by the calcareous nature of the parent material and by erosion which results in destruction and loss of surface at about the same rate as leaching. This accounts for the high alkaline level in the surface soil.
Although the soil throughout the Preserve is dense black clay, it can be divided into alluvial forms along the creek banks and upland in the meadow next to the homestead. However, almost the entire area lies in the flood plain of Maxwell Creek and the degree of flooding would be determined by rainfall intensity. The normal annual rainfall is between 30 - 40 inches. Being located in the Prairie, the vegetation expected would be grasses; however, since most of the are is situated along an existing creek, trees are in abundance. This is characteristic of prairies. Trees of any size and number ar usually found along stream banks or in low lying boggy areas. Since the Preserve is located in the flood plain and subjected to the erosion action of water, any disturbance of the ecosystem should be held to a minimum.
Leonard R Stanislav, Soil Scientist
October 10, 1998