Student Name: Grade:

Torrey Pines Beach FieldTrip #1 Worksheet

geology and tectonics of Coastal San Diego

Coastal Geology of Torrey Pines Beach Bluffs

1) Do the bluff rocks have stacked layers? _____ If so, how many layers do you see? ______

2) What type of rocks make up the bluff? (Circle one) Igneous Sedimentary Metamorphic

3) List the geologic name, age, rock type(s), and genesis for the rock formations making up the bluff.

Formation Name Age (myo) Rock type(s) Depositional Setting

Top Fm. _________________ __________ _____________________ ___________________

Middle Fm. _________________ __________ _____________________ ___________________

Bottom Fm. _________________ __________ _____________________ ___________________

4) What is the general name for the boundary between two rock formations? _____________________

5) Name 4 present-day marine depositional settings where such sediment-rocks currently deposit.

a. _________________ b. _________________ c. _________________ and d. ________________________

6) List 2 viable ways by which the Torrey Pines Sandstone ended up 10’s of meters above sea level.

a) _________________________________ and/or b) _________________________________

7) Based on your newfound understanding of how each of these rock formations were formed within

a unique coastal marine depositional setting(s), explain why the Del Mar Formation is lying directly

beneath the Torrey Pines SS, even though each of these two different rock units deposited in

distinctly different marine environments. Hint: Think about shoreline position and relative changes

in sea level AND your answers to question #7 above.

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Geologic and TEctonic History of San Diego County

8) List the 4 major tectonic periods that San Diego has experienced in its 300 million year history?

1^st Stage ________________________________ Period of Time: _______ to ______ million years ago

2^nd Stage. ________________________________ Period of Time: ______ to ______ million years ago

3^rd Stage ________________________________ Period of Time: ______ to ______ million years ago

4^th Stage ________________________________ Period of Time: ______ million years ago to present

9) Rock type that most likely formed San Diego’s thin, original crust during Stage #1? _____________

10) Today, San Diego has a much thicker, evolved crust - mostly diorite to granite intrusive rock.

The vast majority of those rocks were generated during which of the 4 tectonic periods?__________

11) Del Mar Fm and Torrey Sandstone formed during which of the four tectonic periods? ___________

Observations and Analysis of the Beach Sediment:

12) Color: ____________ Consistent? ____ Grain size: Coarse, medium or fine? _________________

Sand Composition: Light Colored minerals: 1) ____________ 2) ____________ & 3) ____________ = ____%

Dark minerals: 1)____________ 2) ____________ 3)____________, 4)____________ 5) ____________ = ____%

13) What’s the dominant mineral making up the beach sand here? _____________ Why that mineral?

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14) Two major natural sources for sand that replenishes this beach? ____________ and ___________

15) Two major artificial sources for sand that replenishes this beach? ___________ and ___________

Earthquake and Tsunami Hazards of Coastal San Diego:

16) What type of plate boundary runs through Southern California? ________________________

17) The San Andreas Fault System faults represent which tectonic stage of San Diego? ___________

18) Name the active fault that runs just offshore of here, parallel to this beach. ____________________

19) What kind of fault is it? _________________________________

20) What sort of earthquake magnitude and frequency is the Rose Canyon fault capable of?

Maximum quake magnitude? ___________ Frequency of “Big Ones” ? One every ______ years.

21) Is our shoreline susceptible to tsunami? ___________ Why? _______________________________

22) What’s the estimated maximum height for locally-generated tsunami? ___________

23) What’s the estimated time of warning for locally-generated tsunami? ________ How to prepare?

Post Trip Reflection:

24) What did you learn on this trip? How does that relate with what you are learning in this course? _________________________________________________________________________

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25) What did you find interesting and/or important? What did you find difficult and/or challenging? _________________________________________________________________________

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