This packet is everything a parent or guide needs to assess Unit 03 at home — learning targets, the answers that count as correct, the mastery rubric, calibration examples, and a clipboard score sheet. No multiple-choice test: the student shows mastery by naming a rock, naming the environment that made it, and ordering a cliff face from oldest to youngest aloud.
By the end of the Sedimentary Rocks & Stratigraphy unit, a student should be able to:
Six criteria, each judged Not yet / Approaching / Mastered (Page 3).
Identify rocks and order a set of beds by the stratigraphic principles.
The student defends the sequence of time the layers record (Page 4).
Rock ID, depositional environment, and the ordered column kept distinct.
You are making a decision, not adding up points. For each criterion, decide whether the work is Not yet, Approaching, or Mastered — the column language tells you which. A criterion counts as mastered only when the student can both name the rock and defend the sequence of time it records. A student carries three tokens per term; one token buys a re-do of one criterion on another day, so a single bad afternoon never sinks the unit.
Accept any answer in the synonyms column — they are pre-approved as equivalent. The third column flags the confusions that look close but are not yet, so you can coach precisely.
| Canonical answer | Accepted synonyms | Common confusion / discriminator |
|---|---|---|
| Sediment to rock | ||
| Compaction | burial squeezing | Weight of overlying layers presses grains together |
| Cementation | mineral glue | Dissolved minerals precipitate and bind the grains |
| Lithification | sediment turning to rock | The whole compaction + cementation process, in order |
| Rock origins | ||
| Clastic | fragment / detrital rock | Broken pieces cemented together; e.g. sandstone, shale |
| Chemical | precipitated rock | From minerals left as water evaporates; e.g. rock salt, some limestone |
| Organic | biological rock | From living matter; e.g. coal, shelly limestone |
| Depositional environment | where it was laid down | Read from grain size and sorting — beach, river, deep sea, swamp |
| Stratigraphy | ||
| Superposition | oldest on the bottom | In undisturbed layers, each bed is younger than the one below |
| Original horizontality | layers start flat | Tilted beds were deformed after deposition |
| Cross-cutting | cuts are younger | A fault or intrusion is younger than the rock it cuts |
| Unconformity | gap in the record | Missing time — erosion or non-deposition, not a normal layer |
| Criterion | Not yet | Approaching | Mastered |
|---|---|---|---|
| Sediment to rock: compaction & cementation | Cannot describe how loose sediment becomes rock. | Names compaction or cementation but not both, and not in order. | Traces weathered sediment through burial, compaction, and cementation into solid rock. |
| Clastic, chemical & organic rocks | Groups all sedimentary rock together. | Sorts a few rocks but confuses the three origins. | Classifies sandstone, shale, limestone, rock salt, and coal by clastic, chemical, or organic origin. |
| Depositional environment | Cannot connect a rock to where it formed. | Guesses an environment without using grain size or composition. | Reads grain size, sorting, and composition to name the environment — beach, river, deep sea, or swamp. |
| Stratigraphic principles | Cannot order layers or name a principle. | States superposition but misapplies cross-cutting or original horizontality. | Applies superposition, original horizontality, lateral continuity, and cross-cutting to order any sequence of beds. |
| Unconformities & missing time | Reads a rock face as one continuous record. | Spots a break in the layers but cannot explain it. | Recognizes an unconformity and explains the erosion or non-deposition that removed the missing time. |
| Integration (cross-domain) | Treats the science as isolated facts. | Names a link to history, reading, or writing but cannot defend it. | Connects the unit across History · Reading · Writing and defends why it matters. |
The split between Approaching and Mastered is layers as time: not just naming a rock, but using the principles to order a cliff face and explain any gaps. Ask “which is older, and how do you know?”
Read these before you grade. They show what Mastered and Not yet actually sound like, plus the edge cases where you should coach rather than decide on the spot.
Student: ______________________________________ Date: _______________ Guide: _________________________
| # | Criterion | Decision | Notes |
|---|---|---|---|
| 1 | Sediment to rock: compaction & cementation | NY / Appr / Mast | |
| 2 | Clastic, chemical & organic rocks | NY / Appr / Mast | |
| 3 | Depositional environment | NY / Appr / Mast | |
| 4 | Stratigraphic principles | NY / Appr / Mast | |
| 5 | Unconformities & missing time | NY / Appr / Mast | |
| 6 | Integration (cross-domain) | NY / Appr / Mast |
☐ No ☐ Yes — for criterion: __________ Tokens remaining: ☐ 3 ☐ 2 ☐ 1 ☐ 0
NY = Not yet · Appr = Approaching · Mast = Mastered · Unsure between two levels? Circle the lower one and note what a re-do would need.