DSST Introduction to Geology case studies
DSST Introduction to Geology · Put your knowledge to work in context.
The DSST Introduction to Geology is a standardized credit-by-examination option in the Physical Sciences subject area, listed at Level 3 Baccalaureate and worth 3 Semester Hours of credit at institutions that recognize it. It was developed to enable schools to award credit to students for knowledge equivalent to what students learn in a comparable college course, so it suits independent learners, adult students, and service members who already know the material and want credit without seat time. The DSST Introduction to Geology case studies are 5 cases and about 2,954 words.
1Right-Angle Cleavage in a Pegmatite Specimen
During a laboratory practical, a student examines a pale, glassy mineral separated from a granite pegmatite. The specimen has a hardness of about 6.5: it scratches a steel file but is not scratched by a copper coin, and it leaves a white streak.
580 words, about 3 min2Sediment Starvation Below a Dam
A 120-km river flows below a 60-m-tall dam completed 40 years ago. The reservoir traps about 90% of the bed load and a large share of suspended sand.
591 words, about 3 min3Locked Megathrust Near a Coastal Hospital Site
A coastal city of 400,000 people sits above a subduction megathrust. GPS stations show the coast moving 38 mm/yr toward the trench, but the seaward 60 km of the plate boundary is locked from 15 to 40 km depth.
565 words, about 3 min4Landfill Plume in a Sand Aquifer
A closed municipal landfill overlies a 12-m-thick sand aquifer. Monitoring wells show a leachate plume whose leading edge for a conservative chloride tracer is 600 m downgradient after 25 years of leakage; a reactive contaminant of concern has a retardation factor of 3.
662 words, about 3 min5Road Cut Through Dipping Shales
A mountainous highway was widened by cutting a 12-m-high, 45° slope into interbedded sandstone and clay-rich shale. Bedding dips 22° toward the road, and a 2–5 cm bentonite seam lies parallel to bedding about 4 m above the road.
556 words, about 3 min