Creating a Geologic Cross-Section
The following exercise provides an overview of how to create cross sections and use them as a scientific evaluation tool. Geologic cross sections provide a two-dimensional slice of Earth’s subsurface and are used to help understand geologic conditions. Creating and evaluating cross sections is an important aspect of the geoscience profession.
A map and borehole logs are required to create a geologic cross section, and it is common to increase the vertical scale of a cross section to view geologic details. The Woburn trial involved an interesting use of “vertical exaggeration.”
Laying out the Data
The attached link contains an example of a geologic map and cross section. This is a typical layout for setting up the horizontal and vertical scales. The blank spaces below the cross section are intended to be color-coded to show the different colors used to identify each lithology.
Some Things to Consider
Assume that each of the wells in the geologic cross section is open or screened, allowing water to enter the wellbore only over the bottom 10 feet. Which wells appear to be hydraulically connected to the most permeable material, such as sand or sand and gravel?
How do you describe a geological cross section?
A geological cross-section is a graphic representation of the intersection of geological bodies in the subsurface with a vertical plane of a specific orientation, and it is an approximate model of the real distribution of rocks in depth based on information available on the surface and subsurface.
What are the four things to include on every geological cross section?
A legend, the orientation of the line the cross-section represents on the map, a title, and a scale (e.g., Figure 8.11C) should all be included on every geological cross-section.
What is a stratigraphic cross section?
Stratigraphic section u2014A cutaway view, usually with the vertical scale exaggerated in relation to the horizontal scale, that is designed to show the thicknesses, is also known as ” stratigraphic cross section “.
What is a cross section in math?
Describe the shapes formed by cross-sections (square, rectangle, triangle, etc.). A cross-section is a plane section of a three-dimensional object that is parallel to one of its planes of symmetry or perpendicular to one of its lines of symmetry.
How do you draw a cross in AutoCAD?
How to Make an AutoCAD Mechanical Centerline Cross
- To display the Select Options for Centerlines dialog box, press ENTER, or specify a starting point for the centerline.
- To specify the center point of a hole, click Home tab Draw panel Centerline drop-down Centerline Cross.
How do you scale a cross section?
When compared to the horizontal scale, it is common to increase the vertical scale ratio by an order of magnitude; for example, if the horizontal scale is 1 inch equals 100 feet, a typical vertical scale for the geologic cross section would be 1 inch equals 10 feet.
How do you create a geologic map?
The following are the steps involved in geological mapping:
- Make outcrop observations and write a description of it. Measure the position of rocks (strike and dip), geological structure elements, and other geological elements in a field notebook.
What is cross section and block diagram?
A cross section depicts the earth’s surface (with or without topography or elevation) as well as a vertical slice, whereas a block diagram depicts the earth’s surface as well as at least one cross section, resembling a block or chunk cut out of the earth.
What is a geologic section?
The local geologic column is the sequence of rock strata or lithologic units in a given location.