Instructor Materials - Module 3
Constructing a Geologic Cross Section
Using this Module
A key first step toward developing students' understanding Woburn's water problems is having a students understand the geologic model of the Aberjona River Valley. Geologist use a series of tools to be able to construct models of the subsurface features of a given location. The first step in this tool is to look at these are official features of an area to gain a perspective of the subsurface composition. Geologist typically then will drill borings into the subsurface to obtain samples of rocks. During the drilling process geologist will measure the depth at which changes in rock type occur, they also will try to identify similar rock types and different borings to come up with a spatial arrangement of rock layers. This data is then used to construct the geologic cross-section. So the objective of this module is to get students familiar with its surface and subsurface geologic features so that they may begin to interpret the interrelation between geology and hydrogeology. Geologic logs are provided for students to create their own subsurface geologic cross-sections, which can be applied to later modules when they begin to evaluate groundwater flow towards Wells G & H.
This module assumes some in-class lecture regarding the principles of rock formation and landscape creation. Discussions should also include the effects of glaciation in the creation of a buried valley that result from glacial erosion and post-glacial deposition. Information regarding glacial processes is available at the Landforms of Glaciation webpage. The level of detail regarding the local geology and geologic processes is at the discretion of the instructor. If the goal of being module is to have students interpret the geologic conditions, then the lecture and background information necessary may require three to five class sessions. If the goal is to have students construct a cross section without its interpretation, this can be completed in a 1 to 2-hour lecture/laboratory period. The process for creating cross sections is shown on the student assignment page Creating a Cross-Section.