SCIENCE · INVESTIGATE AND EXPLAIN

Reconstruct all histories consistent with a cross-cutting packet

A geological history can be represented as constraints rather than a guessed story. If feature X cuts feature Y, X is younger than Y under the stated identities. If a younger cover seals a fault, faulting predates the cover. Each relationship supplies an edge from older event to younger event.

Learning outcome: Reconstruct each edge directly from the supplied diagram and relationship table. Conceal the intersection, list every remaining valid order and specify the one additional observation that would distinguish them. Do not infer age from drawing left/right position.

Starting recap

Distinguish present position, relative event order, numerical age and duration. Preserve calibrated ranges, clock assumptions and missing observations instead of forcing one history.

All lessons are open directly. Your saved experiments remain when you leave and return.

Try

The visible offset establishes intrusion before fault, and the sealing cover is last. Removing only that offset leaves intrusion versus fault unresolved; the other relationships still constrain the same three boundary positions.

Open the experiment

Predict

Which event order becomes unresolved if one intersection is concealed?

Your prediction and reason

Experiment

Reconstruct each edge directly from the supplied diagram and relationship table. Conceal the intersection, list every remaining valid order and specify the one additional observation that would distinguish them. Do not infer age from drawing left/right position.

Enumerate event histories consistent with observed relationships

Worked teaching model · synthetic values · Invented section: bed A predates B; intrusion I cuts both; fault F offsets both; cover C seals I and F. When visible, F also offsets I. No other ordering evidence. Complete permutations of five events are tested; consistency is not posterior probability.

Intrusion/fault intersection observed0 or concealed1: 0 code Candidate order: A B I F C0 or A B F I C1: 0 code

Reset keeps your prediction, captures and practice history.

Concealing one relationship can leave multiple equally consistent event orders.

A single surviving sequence is conditional on complete body identification and stated relationships. If a fault is sealed by cover, it predates that cover; its current line position is not an absolute clock.

Each edge encodes one observed relationship below. This graph displays chronological constraints, not a surveyed cross-section. The first facing lesson supplies the separate original stratigraphic section diagram.

Complete supplied relationships
A / B	B deposited after A
I / beds	I cuts A and B
F / beds	F offsets A and B
C / I,F	C seals both
I / F	F offsets I; I is older

Compatible order 1: A → B → I → F → C

Complete conditional quantities
Quantity	Value	Unit
Permutations examined	120	orders
Compatible orders	1	orders
Selected candidate compatible	1	0 no / 1 yes

These are invented observation packets and calculations, not mapped field records or laboratory isotope measurements. Retain the source assumptions and first reasoning separately from public feedback.

Concealing one relationship can leave multiple equally consistent event orders.

Observation to attach to a capture

Captures preserve recipes and replay their calculated results. They are synthetic model evidence, not physical measurements.

Understand

1. Define the time interpretation

2. Connect observations, mechanism and assumptions

The original fictional packet has deposition A before B, intrusion I cutting both beds, fault F offsetting both beds and cover C sealing both intrusion and fault. A visible intersection additionally shows F offsetting I. These observations give A before B, B before I and F, I and F before C, and optionally I before F.

The model enumerates all 120 orders of five distinct events and retains those satisfying every edge. With the intrusion/fault intersection visible, only A,B,I,F,C remains. Concealing that intersection admits A,B,F,I,C as well. A partial order can therefore be informative without supplying one total sequence.

Consistency is not probability or proof that no omitted event occurred. Actual mapping must resolve body correlations, fault reactivation and repeated intrusive generations. A contradiction should prompt an observation audit or a richer model, not a selective deletion of inconvenient evidence.

3. Reconstruct the worked packet

4. Predict and investigate

Predict first: Which event order becomes unresolved if one intersection is concealed?

5. Test a changed case

Apply the evidence to a changed case

When the intrusion/fault intersection is concealed, is A,B,F,I,C allowed? Does the cover remain youngest?

Retain the chronology, calculations and assumptions before opening public feedback.

Compare a worked response

Yes. Both I and F are younger than B and older than C, but neither is then ordered relative to the other. C remains last under the sealing observations.

6. Retain a defensible observation notebook

Preserve the original prediction, complete observations/relationships, calculations, uncertainty convention and rejected alternative. All sections and isotope packets here are invented instructional cases, not actual mapped outcrops or measured isotope analyses. Public practice is not independent reasoning review or supervised field competence.

Method and mechanism reference, checked 30 October 2026. Original prose, diagrams, numerical packets and exercises.

Apply

Public practice checks a specific claim. It does not establish independent mastery.

When the intrusion/fault intersection is concealed, is A,B,F,I,C allowed? Does the cover remain youngest?

Your explanation and limitations

Continue

Completion requires a saved prediction, at least one capture and a reflection. Presence checks do not grade your reasoning.

Skipping retains experiments and awards no mastery.

Previous: Establish stratigraphic facing before applying superposition Next: Bound missing time without assigning it all to erosion

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