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We can extract zircons, a radioactive mineral, from sample Y to obtain a time since the minerals formed- thereby providing the numeric age of this layer.Within the zircons in this rock sample, the ratio of parent to daughter isotopes is 15.5:0.5. Using the chart below, determine how many half lives have passed.

At the top of the sequence you find a rock (sample 7) that bubbles when in contact with acid. Inspect sample 7 further:

Inspect the following image (the red line illustrates the location of the equator). Is this an accurate representation of the planet’s historical supercontinent? (consult the relevant maps-think about Alfred Wegener’s evidences for continental drift)

This is a satellite image of the volcano on which sample 3 was collected. Along the flank of this volcano, we see several puzzling circular features (see image below). What are these?

At the base of the sequence you find a rock (sample 9). It feels like sandpaper against your fingers. Inspect sample 9 further:

Sample 6 is found in a layer featuring pink granite dikes, overlain by a clastic sediment layer. At the boundary between the two layers, there is an unconformity (red line). What kind of unconformity is it?  

According to what you know about samples 7-9, which are true of the landscape at this location over time? (Mark all that apply. Think about where the oldest vs youngest rock layer is in the sequence.)

A lone volcano rests in the ocean at the head of a seamount chain (see Volcanoes map). Inspect sample 3 taken from this area to better understand what is happening at this location:

Inspect the following image. Based on what you know, is this an accurate representation of the planet’s current plate boundaries? (Consider the location of the boundaries and the type of boundaries illustrated. Consult the relevant maps up at the start and the answers to your previous questions.)

In the center of the largest continent, you find a very soft evaporite mineral called gypsum (sample 6).