Rock Layer Activity You will be acting as geologists examining two stacks of rock layers, one in Montana and one in France. Your job is to determine: a. Which layers (strata) in Montana correlate with (are the same as the) strata in France (by matching letters), b. Which layer in France contains the same dinosaur fossil as layer in Montana.

Directions Using one color connect the borders of the rock layers in Montana with those in France. This is your hypothesis. Now, Predict what layer the dinosaur fossil would in found in France. Explain your reasoning.

Create your Hypothesis: For Example

Directions Using your pencil and the information shown in Figure 2, draw the fossils in the layers shown on the chart. Only one fossil be drawn in each space. Using a colored pencil different from that used in you hypothesis, now connect the layers using the fossil evidence they have just drawn.

Activity Key

How Do Rock Layers Become Disturbed? Some examples: (Add to Vocab Section) Faults Intrusions Folding Tilting

Faults A break in the Earth’s crust Block of crust slides relative to one another Faults can be normal, reverse & strike slip

Hanging & Foot Walls We classify faults by how the two rocky blocks on either side of a fault move relative to each other. Foot Wall. The side that shows the fault and arrows indicating movement. The block that is shaped kind of like a foot. That's the foot wall. If it's resting or hanging on top of the footwall block that's the hanging wall. Here's another way to think of it: the hanging wall block is always above the fault plane, while the foot wall block is always below the fault plane.

Hanging & Foot Walls

Types of Faults Normal Fault – Hanging wall moves down relative to footwall at a divergent boundary. Reverse Fault – Hanging wall moves up relative to footwall at a convergent boundary. Strike Slip Fault – Rock on either side of the fault slides horizontally to each other at a transform boundary.

Faulted Rock

Faulted Rock

Normal Fault Rock

Reverse Fault Rocks

Strike Slip Fault Rocks

Intrusions (Igneous Rock) Molten rock from the Earth’s interior squeezes into already existing rock & cools

Igneous Intrusion

Igneous Intrusion

Igneous Intrusion

Folding Rock layer bend and buckle from Earth’s internal forces.

Anticline A ridge-shaped fold of stratified rock in which the strata slope downward from the crest.

Syncline A trough or fold of stratified rock in which the strata slope upward from the axis.

Folded Rock

Folded Rock

Anticline & Syncline Rock

Tilting Internal forces slant rock layers

Tilted Rock

Tilted Rock

Relative Age Dating Unconformity = any gap in the rock record caused by erosion or a period of non-deposition – missing time Angular Unconformity = younger, flat strata (layer) above older, eroded/tilted or folded sedimentary rock Unconformities can be caused by weathering/erosion or non-deposition and represent missing time. Rock on top can be 500million years old while rock on bottom is 1b years old. There would be a missing 500million years.

Angular Unconformity

Angular Unconformity Grand Canyon Arizona USA

Angular Unconformity Friar’s Point Barry Island South Wales