The Red Clay Creek has flowed through the rolling hills of northern Delaware for many thousands of years, cutting a deep valley into the old deformed rocks of the Appalachian Piedmont. The Red Clay valley contains many of the common rocks found throughout the Delaware Piedmont.
The Setters Formation, identified on the southeast side of Pleasant Hill valley in well Cb13-16, contains the prograde mineral assemblages (1) microcline, biotite, and sillimanite +/- garnet, and (2) microcline, biotite, sillimanite, and muscovite +/- garnet. These pelitic assemblages allow us to infer peak metamorphic conditions between 620Â° and 680Â°C and 4 to 6 kilobars pressure, if PH20/Pfluid is > 0.5. There is some evidence in the drill cuttings to indicate that partial melting accompanied the formation of sillimanite, thus constraining peak temperature to > 640Â°C.
The Delaware Academy of Science has been instrumental in informing Delaware citizens about science and utilization of local resources. Since 1970 the annual meeting of the Delaware Academy of Science has been used as a time for presentation of ongoing research in various areas of science in the Delaware region. The proceedings of these meetings have resulted in publication of transactions of the Delaware Academy of Science. The 1976 annual meeting focused on aspects of the geology of Delaware.
Greensand is composed primarily of the mineral glauconite -- a potassium, iron, aluminum silicate. In some Delaware greensands, the glauconite content exceeds 90%. The remaining 10% is mainly quartz. In the past, greensand was used in Delaware as an inexpensive fertilizer. The only active greensand mine in the U.S. today is in New Jersey. Once mined, greensand is dried and used as a soil conditioner. Greensand is also used in water softeners primarily to remove iron from the water. Recent research has shown that greensand has the potential for use as a filter of heavy metals from industrial waste water and landfill leachates.
Sand and gravel are essential for supporting and maintaining economic development throughout Delaware. These natural resources are used primarily for aggregate in the productions of concrete for residential, commercial, and industrial buildings, bridge and highway construction, fill for road beds and foundations, water and wastewater treatment facilities, and for replenishment of our Atlantic and Delaware Bay beaches.
A visit to Woodlawn Quarry is suitable for ages 10 to adults and provides an interesting opportunity to observe common mineral specimens, identify the quarry as an early mining site, appreciate the physical work necessary to quarry rock with hand tools, and discuss the economic importance of the minerals found in the quarry. The minerals that can be readily found and identified in the quarry are feldspar, quartz and mica.
The Delaware Geological Survey, in cooperation with the U. S. Bureau of Mines, has investigated glauconite-bearing greensand deposits in Delaware for several years. The purpose of this effort is to find possible practical uses for this potentially important mineral resource. This report briefly describes the preliminary results of one phase of the study: application of greensands to the purification of industrial waste waters.
In the greater Dover area sodium concentrations in ground water from the glauconitic Piney Point Formation commonly exceed 100 parts per million. Investigation of chemical characteristics of the water, and statistical analyses of the results, show that these high concentrations are due to a natural ion-exchange process. Calcium in water replaces sodium in the mineral glauconite and causes the sodium enrichment in ground water.