The Lithostratigraphic Framework of the Hertfordshire County of Essay

The Lithostratigraphic Framework of the Hertfordshire County of England - Essay Example The Hertfordshire County of England has a young history geologically. The lithology of this area is largely composed of Quaternary and Tertiary deposits, with some glacial movement effects at its northern reaches.   With the sandy conditions of the shores on its eastern side, you might say Hertfordshire is between a small rock and a big hard place. Formations, a principal mapping unit (enquire.com 2006), will be briefly described as to their importance in this report. The status of current ground conditions will also be presented as they affect the analysis of the area. Then geohazards, or expected/probable problems, will be considered. The objective of this report is to provide information that subsequent investigations could use. As in other Home Counties, Hertfordshire shares a common pattern of development from the 17th century, except for its construction of the New River in the Lea Valley that supplies London with water. The majority of settlements built in the times of the N ormans were in the northeast. The Abbey of St. Albans, a major landowner, influenced land management strongly, including the formation of hunting parks, which Hertfordshire has had in abundance. Agriculture displaced many of these parks, and then they were wooded again. A boom in the 16th century of the country-house building came after lands were confiscated by the Crown. The number of palaces from the 1700's were many because of the "rich soil and wholesome air" that attracted wealthy people. (enquire.com 2006) Other building came along the river valleys, slowly. But the industry of malting and brewing in the late 19th century created an era of strong development. The decades since the mid-1900's has seen major changes in the landscape of Hertfordshire.  Ã‚  The development of Portland cement in the early 1900's, that uses gravel deposits in its composition, brought about quarries and industry related to it (HGS 2005). Quarries have also been necessary for researching the strata of the land.  Modern construction has been largely in the south/southwest part of the county. This report, focusing on Stevenage and Ware, is for development purposes in the northern sections of the county.  Near Ashwell is the Steeple Morden Plantation Quarry that allows geologists to see the layers of rock. In trenches cut into the quarry, the color contrasts between Melbourn Rock and the soft chalk is obvious. The gray Plenus Marls and Melbourn Rock that were once thought to be the base of the Middle Chalk (HGS 2005) is now considered the marker horizon while shelly detrital rock is above that and smooth chalk above that. The eight beds of the Plenus Marls can be traced to the Paris Basin and used as a marker horizon across Europe, "indicating a change in anoxic conditions" (HGS 2005).There is a lack of clay-with-flints this quarry. Quarry section showing chalky outwash gravel of Anglian age overlying river gravel of proto-Thames (photo by John Carr) (RIGS 2003) The formations and types of sediments in Hertfordshire will be discussed as they pertain to development, and also as they pertain to restrictions of use (RIGS 2003). Besides the geohazards possible in any construction site, there are also hazards to the geology of a site from construction. All this must be taken into consideration before building can begin. Former construction through the ages has not taken this into account and there has been a degeneration of soils as well as destruction to the buildings by swallow holes and other phenomenon.