1. Wednesday 1/25/17
Notebook Entry: Describe 3 features of the rocks in this picture. Pick features you think are clues to the story of how these rocks.

2. This small Jack Hills zircon (50 micrometers is about the width of a human hair) crystallized slowly. The crystal grew from the core (left) to the rim (right). As crystals form, they incorporate chemicals from their surroundings. (Image courtesy Bruce Watson, Rensselaer)
The bits and pieces of rocks - quartzite / metaconglomerate - that make up the Jack Hills rock formation are ancient—over 3 billion years old.
Individual crystals of zircon within the rocks are 4.4 billion years old, only 150 million years or so younger than the age of the Earth itself. These crystals are the oldest fragments of the Earth yet found. (Photograph copyright Bruce Watson, Rensselaer)

3. Rocks Tell A Story
Different rocks form under only certain conditions and even the dullest gray lump of a rock can tell us something important about the past.
Some types of things that rocks can tell us about our planet as well as other planets are:
Was there a lake or a volcano present where the rock was found?
Was there a mountain range or a sea?
Was it hot or cold?
Was the atmosphere thick or thin?

4. Igneous Rocks – ‘fire rocks’
Igneous rocks are made from cooling magma or lava

5. Sedimentary Rocks – ‘sandwich rocks’
For millions of years, rocks on earth’s surface have been broken up by weathering and carried to other places by erosion
Thick layers of sediment build up gradually over millions of years
The weight of old layers squeeze older sediments together and is called compaction

6. Metamorphic Rock – ‘changing rocks’
Metamorphic rocks are rocks that have “morphed” or changed into another kind of rock.
Through heat and/or pressure a rock changes into another rock
These rocks could originally be any of the 3 types.

7. Which Rock Came First?
All 3 types of rocks are connected
Processes on Earth are always changing rocks from one type to another.

8. Which Rock Came First?
Use this graphic to help you hypothesize different sequences in which the three rocks could have formed.