Topic Selection & Fit (epsl-topic-selection)

EPSL's identity is in its name: Letters. The journal wants a short paper whose single result moves a frontier — how planets differentiate, how mantles convect, how faults load, how climate signals enter the rock record — not a competent study whose relevance stops at one basin, one orogen, or one sample suite. Deciding fit early saves months, because the frontier-vs-incremental judgment is made at the editor's desk.

When to trigger

• Choosing between EPSL and a specialist or regional venue
• Sharpening a dataset into a process-level question
• Worried the paper reads as "another case study from region X"
• Tempted to split one project into companion papers (EPSL discourages this)

The process-level test

1. Name the process, not the place. Does the result constrain a physical, chemical, or mechanical process of the Earth or another planet — melting, degassing, core formation, slab dehydration, crustal growth, orbital forcing — rather than describing a locality?
2. Portability. Would a scientist working on a different continent (or a different planet) change how they interpret their system because of your result?
3. Decisiveness. Does the dataset actually discriminate between competing hypotheses, or is it consistent with all of them?
4. Letter economy. Can the advance be delivered in a main text near the ~6,500-word cap (re-check on the official site) with a handful of figures? If not, the venue or the scope is wrong.

Fit-versus-redirect decision table

Your work is...	EPSL fit	Better home
A locality's geochemistry with no generalizable mechanism	weak	Lithos, Chemical Geology, a regional journal
A new constraint that rewrites a global process budget	strong	EPSL Letter
Comprehensive method development for one instrument	weak	Chemical Geology, G-cubed, GGR
A planetary-interior result from mission or meteorite data	strong	EPSL Letter (planetary scope is explicit)
Descriptive stratigraphy or mapping	weak	Basin Research, GSA Bulletin
A dense monograph-length argument	wrong format	JGR Solid Earth, GCA
A field-wide synthesis you were invited to write	strong	EPSL Frontiers Paper (invitation only)

Worked micro-example (illustrative — three framings of one detrital-zircon dataset)

The same 600-grain U-Pb dataset from a foreland basin can land three ways (illustrative):

• Off-fit: "Detrital zircon ages from the X Basin constrain its provenance." A locality's sediment-routing story — the textbook EPSL desk decline.
• Borderline: "Age spectra shift at 30 Ma, coincident with the Y collision." A correlation, but a reviewer asks what process was tested.
• On-fit: "Foreland age spectra lag exhumation by ~5 Myr (illustrative), quantifying the transit time of orogenic detritus — so detrital archives worldwide record mountain building with a measurable, correctable delay." Now every basin worker recalibrates their reading of the archive.

The sorting question: finish the sentence "anyone studying [process] on any planet now has to account for…". If you can only finish "anyone studying [my region]…", reframe or redirect.

Anti-patterns

• A regional case study whose conclusions never leave the field area — the pattern EPSL editors decline without review
• "First measurement of X in Y" with no hypothesis the measurement discriminates
• Stretching a specialist method paper to look like a process paper
• Planning two companion manuscripts; EPSL states they are against the spirit of concise Letters
• Choosing EPSL because of prestige while the natural readership is a single sub-community

Output format

【Question】one-sentence process-level question
【Process, not place】the Earth/planetary process constrained
【Portability】who outside the region/sub-field must respond
【Decisiveness】hypotheses discriminated
【Letter economy】deliverable near the word cap? [Y/N]
【Verdict】EPSL Letter / reframe / redirect (venue)
【Next】epsl-literature-positioning

Supplementary resources

• ../../resources/exemplars/library.md — landmark EPSL papers that cleared the frontier bar
• ../../resources/official-source-map.md — EPSL aims, scope, and article types