{
  "schema_version": 1,
  "title": "Bryce Geology Lab — claims, evidence and limits",
  "retrieved_at": "2026-10-02",
  "review_status": "Author source audit; independent geologist review pending",
  "sources": [
    {
      "id": "S1",
      "title": "Hoodoos",
      "publisher": "National Park Service, Bryce Canyon National Park",
      "url": "https://www.nps.gov/brca/learn/nature/hoodoos.htm",
      "published_or_updated": "2021-09-04",
      "retrieved_at": "2026-10-02",
      "license": "Facts paraphrased and linked; no text or illustrations reproduced. Page contains third-party imagery, which is not reused.",
      "supports": "Weathering/erosion distinction; water and frost; depositional setting; variable resistance."
    },
    {
      "id": "S2",
      "title": "Wall and Narrows",
      "publisher": "National Park Service, Bryce Canyon National Park",
      "url": "https://www.nps.gov/brca/learn/nature/wallandnarrows.htm",
      "published_or_updated": "2021-09-04",
      "retrieved_at": "2026-10-02",
      "license": "Facts paraphrased and linked; no media reused.",
      "supports": "Fins bounded by fractures; runoff removes weathered fragments; differential erosion."
    },
    {
      "id": "S3",
      "title": "Arches",
      "publisher": "National Park Service, Bryce Canyon National Park",
      "url": "https://www.nps.gov/brca/learn/nature/arches.htm",
      "published_or_updated": "2015-02-24",
      "retrieved_at": "2026-10-02",
      "license": "Facts paraphrased and linked; no media reused.",
      "supports": "Windows in fins; gravity; qualified bridge/arch terminology; Natural Bridge as an example."
    },
    {
      "id": "S4",
      "title": "NPS Geodiversity Atlas—Bryce Canyon National Park, Utah",
      "publisher": "National Park Service, Geologic Resources Inventory",
      "url": "https://www.nps.gov/articles/nps-geodiversity-atlas-bryce-canyon-national-park.htm",
      "published_or_updated": "2024-06-17",
      "retrieved_at": "2026-10-02",
      "license": "Facts paraphrased and linked; no map or photograph reproduced.",
      "supports": "Joint-controlled landforms; horseshoe-shaped amphitheaters; Claron on the Paunsaugunt rim."
    },
    {
      "id": "S5",
      "title": "Geologic map of Bryce Canyon National Park and vicinity, southwestern Utah (I-2108)",
      "publisher": "US Geological Survey",
      "authors": "William E. Bowers",
      "url": "https://www.usgs.gov/maps/geologic-map-bryce-canyon-national-park-and-vicinity-southwestern-utah",
      "document_url": "https://pubs.usgs.gov/imap/2108/report.pdf",
      "published_or_updated": "1991 (USGS catalogue); map commonly cited as 1990",
      "retrieved_at": "2026-10-02",
      "license": "USGS report retained privately as reading evidence; only facts and original diagrams delivered publicly. No plate traced or republished.",
      "verified_portions": "Report printed pp. 2–4 (PDF pp. 4–6) visually read. Report downloaded successfully through curl after web-tool 403. Entire map plate not audited.",
      "supports": "Lower pink and upper white informal members; local variation and missing white member; bed resistance interpreted in earlier field studies; contacts are not inferred from lidar."
    },
    {
      "id": "S6",
      "title": "Deciphering Nature’s Palette wayside",
      "publisher": "National Park Service, Bryce Canyon National Park",
      "url": "https://www.nps.gov/places/deciphering-nature-s-palette-wayside.htm",
      "published_or_updated": "2024-01-08",
      "retrieved_at": "2026-10-02",
      "license": "Facts paraphrased and linked; wayside artwork not reproduced.",
      "supports": "Upper white/lower pink terminology; limestone with silt/clay and interbedded materials; introductory age range."
    },
    {
      "id": "S7",
      "title": "Mapping Geologic Hazards in and Near Bryce Canyon National Park",
      "publisher": "Utah Geological Survey, Survey Notes 55(2)",
      "authors": "Tyler Knudsen",
      "url": "https://geology.utah.gov/map-pub/survey-notes/mapping-geologic-hazards-in-and-near-bryce-canyon-national-park/",
      "published_or_updated": "2023-05-01",
      "retrieved_at": "2026-10-02",
      "license": "Facts paraphrased and linked; no photographs/maps reused; government domain is not treated as a blanket media license.",
      "supports": "Eastern escarpment, drainage contrast and active mass wasting; broad regional age range."
    },
    {
      "id": "S8",
      "title": "Interim geologic map of the Parowan quadrangle, Iron County, Utah (OFR-764)",
      "publisher": "Utah Geological Survey",
      "authors": "Tyler R. Knudsen",
      "url": "https://ugspub.nr.utah.gov/publications/open_file_reports/ofr-764/ofr-764.pdf",
      "doi": "10.34191/OFR-764",
      "published_or_updated": "2024",
      "retrieved_at": "2026-10-02",
      "license": "Reading copy retained outside public/. Facts paraphrased; no map, text, or illustration republished. Source is an interim, minimally reviewed open-file report.",
      "verified_portions": "Printed p. 12 stratigraphic discussion and p. 13 member descriptions; source scope is Parowan/Markagunt, with explicit discussion of evidence near Bryce.",
      "supports": "Fluvial, floodplain and lake environments; soil modification; revised local-versus-regional age interpretation. Does not supply a new Bryce geologic map."
    },
    {
      "id": "S9",
      "title": "Bedrock Fracture by Ice Segregation in Cold Regions",
      "publisher": "Science 314(5802), 1127–1129",
      "authors": "Julian B. Murton, Rorik Peterson and Jean-Claude Ozouf",
      "url": "https://doi.org/10.1126/science.1132127",
      "abstract_url": "https://pubmed.ncbi.nlm.nih.gov/17110573/",
      "published_or_updated": "2006-11-17",
      "retrieved_at": "2026-10-02",
      "license": "Copyright AAAS; abstract findings briefly paraphrased, no figures or article text reproduced.",
      "verified_portions": "Original article abstract through NLM indexed record, plus publicly indexed article text. No new Bryce measurements.",
      "supports": "Ice segregation can fracture porous bedrock under experimental freezing regimes; simple freeze-count or volume-expansion explanations are incomplete."
    },
    {
      "id": "S10",
      "title": "Geology of Bryce Canyon National Park",
      "publisher": "US Geological Survey, Geology and Ecology of National Parks",
      "url": "https://www.usgs.gov/geology-and-ecology-of-national-parks/geology-bryce-canyon-national-park",
      "published_or_updated": null,
      "retrieved_at": "2026-10-02",
      "license": "Facts paraphrased and linked; no diagrams/photos copied.",
      "supports": "Carbonate dissolution in weakly acidic water; sedimentary rock record. Loose grouping of named units in the overview is not used as a stratigraphic authority."
    },
    {
      "id": "S11",
      "title": "Grand Staircase",
      "publisher": "National Park Service, Bryce Canyon National Park",
      "url": "https://www.nps.gov/brca/learn/nature/grandstaircase.htm",
      "published_or_updated": null,
      "retrieved_at": "2026-10-02",
      "license": "Facts paraphrased and linked; no diagram copied.",
      "supports": "Regional sequence across Bryce, Zion and Grand Canyon; broad setting only."
    },
    {
      "id": "A1",
      "title": "Existing BCC Thor’s Hammer reconstruction and methods",
      "publisher": "BCC local frozen website",
      "url": "../../methods.html#thors-hammer-model",
      "published_or_updated": "2026-09-30",
      "retrieved_at": "2026-10-02",
      "license": "USGS 3DEP source public domain; NPS photograph explicit public-domain constraint in inherited attribution; OSM location ODbL. BCC interpretation and original code retained. Fresh NPS Gallery metadata fetch unavailable; rights record inherited, not independently revalidated.",
      "supports": "Model geometry/axis, interpreted bed intervals, poster, source resolution and limits; not a sampled stratigraphic section."
    },
    {
      "id": "A2",
      "title": "Existing BCC Natural Bridge reconstruction and methods",
      "publisher": "BCC local frozen website",
      "url": "../../methods.html#natural-bridge-model",
      "published_or_updated": "2026-09-30",
      "retrieved_at": "2026-10-02",
      "license": "USGS lidar and credited USGS photograph public domain in inherited attribution; OSM location ODbL. Existing interpreted poster reused unchanged.",
      "supports": "Source-backed reconstructed landmark context, with an interpreted opening; not photographic evidence."
    },
    {
      "id": "A3",
      "title": "Existing BCC landscape model and methods",
      "publisher": "BCC local frozen website",
      "url": "../../methods.html#model",
      "published_or_updated": "2026-09-30",
      "retrieved_at": "2026-10-02",
      "license": "USGS 3DEP and USDA NAIP public domain in inherited attribution; OSM locations ODbL. Existing poster reused unchanged.",
      "supports": "Derived amphitheater view; elevation shading and image color do not map formation boundaries."
    },
    {
      "id": "S12",
      "title": "NPS Stratotype Inventory",
      "publisher": "National Park Service, Geology",
      "url": "https://www.nps.gov/subjects/geology/nps-stratotype-inventory.htm",
      "published_or_updated": null,
      "retrieved_at": "2026-10-02",
      "license": "Definitions paraphrased and linked; no imagery or text reproduced.",
      "supports": "Hierarchy of formation, member and bed; mapping requires multiple geological properties."
    }
  ],
  "claims": [
    {
      "id": "C01",
      "claim": "Weathering changes rock; erosion transports material.",
      "sources": [
        "S1"
      ],
      "status": "source-supported",
      "limits": "Processes interact; the model’s separation is pedagogical."
    },
    {
      "id": "C02",
      "claim": "Fractures provide weaknesses around which fins, openings and columns develop.",
      "sources": [
        "S2",
        "S4"
      ],
      "status": "source-supported",
      "limits": "A joint is not automatically a fault; no joint map or origin is reconstructed here."
    },
    {
      "id": "C03",
      "claim": "Water and freezing conditions can damage rock.",
      "sources": [
        "S1",
        "S9"
      ],
      "status": "source-supported",
      "limits": "Air-temperature crossings are not equivalent to successful rock-fracture events; moisture, rock and thermal conditions matter."
    },
    {
      "id": "C04",
      "claim": "Weakly acidic water can dissolve carbonate minerals/cement.",
      "sources": [
        "S10"
      ],
      "status": "source-supported",
      "limits": "No chemistry, pH, reaction rate or dolomite immunity is claimed."
    },
    {
      "id": "C05",
      "claim": "Runoff helps remove broken material; gravity also moves rock.",
      "sources": [
        "S2",
        "S3",
        "S7"
      ],
      "status": "source-supported",
      "limits": "No hydrology, talus mechanics or slope stability is solved."
    },
    {
      "id": "C06",
      "claim": "Contrasting resistance contributes to ledges and recesses.",
      "sources": [
        "S1",
        "S5"
      ],
      "status": "source-supported",
      "limits": "Mineralogy, cementation and texture matter; color alone does not measure resistance."
    },
    {
      "id": "C07",
      "claim": "Fin, window and hoodoo describe different landform shapes.",
      "sources": [
        "S2",
        "S3"
      ],
      "status": "source-supported",
      "limits": "The simplified sequence is not compulsory for every pillar and is not a dated reconstruction."
    },
    {
      "id": "C08",
      "claim": "Bryce’s amphitheaters occupy the eroding plateau margin.",
      "sources": [
        "S4",
        "S7"
      ],
      "status": "source-supported",
      "limits": "Do not imply that water erosion is absent merely because Bryce differs from a single river-cut canyon."
    },
    {
      "id": "C09",
      "claim": "Natural Bridge is discussed by NPS among arches/windows.",
      "sources": [
        "S3"
      ],
      "status": "source-supported",
      "limits": "Bridge/arch process terminology is imprecise; a place name alone is not proof of its origin."
    },
    {
      "id": "C10",
      "claim": "Claron’s informal white member overlies its pink member where both remain.",
      "sources": [
        "S5",
        "S6"
      ],
      "status": "source-supported",
      "limits": "Not continuous everywhere; not every white patch is the white member."
    },
    {
      "id": "C11",
      "claim": "Sediment accumulated in varied stream, floodplain and lake settings and was modified by soils.",
      "sources": [
        "S8"
      ],
      "status": "source-supported",
      "limits": "Regional synthesis; no particular ancient shoreline is reconstructed."
    },
    {
      "id": "C12",
      "claim": "Rock age and the age of a present landform are different questions.",
      "sources": [
        "S1",
        "S8"
      ],
      "status": "interpretation of source sequence",
      "limits": "No isolation date is assigned to a hoodoo."
    },
    {
      "id": "C13",
      "claim": "The section’s Thor outline is derived from the copied reconstruction.",
      "sources": [
        "A1"
      ],
      "status": "derived",
      "limits": "2018 lidar, photograph-adjusted widths and reconstructed hidden shape; 0.2 m model rows are not positional accuracy."
    },
    {
      "id": "C14",
      "claim": "Thor’s colored resistance intervals are interpretations from shape.",
      "sources": [
        "A1"
      ],
      "status": "interpretative",
      "limits": "No sampled beds, formation contacts, or subsurface boundaries; never relabel these as mapped units."
    },
    {
      "id": "C15",
      "claim": "The weathering experiments are deterministic rule-based illustrations.",
      "sources": [],
      "status": "original implementation",
      "limits": "Dimensionless coefficients, cells and steps; no measured geometry, real duration, rates, climate projection or collapse forecast."
    },
    {
      "id": "C16",
      "claim": "Published introductory ages vary in scope and precision.",
      "sources": [
        "S1",
        "S6",
        "S7",
        "S8"
      ],
      "status": "source comparison",
      "limits": "Do not average 50 Ma, 50–60 Ma and 65–35 Ma into a new date. Recent regional synthesis discusses Early Eocene evidence near Bryce; local refinement requires expert review."
    },
    {
      "id": "C17",
      "claim": "The regional layer drawing conveys order, not thickness or position.",
      "sources": [
        "S5",
        "S11"
      ],
      "status": "illustrative",
      "limits": "No GIS contacts, coordinates, geographic/vertical datum or scale; missing time and lateral changes omitted."
    },
    {
      "id": "C18",
      "claim": "More evidence is needed to infer material strength or timing from a picture.",
      "sources": [
        "A1",
        "S9"
      ],
      "status": "learning interpretation",
      "limits": "The field challenges evaluate evidence boundaries, not real-site stability."
    },
    {
      "id": "C19",
      "claim": "Formations, members and beds are different levels of stratigraphic classification.",
      "sources": [
        "S12"
      ],
      "status": "source-supported",
      "limits": "A shape or color by itself does not establish a mapped unit."
    }
  ],
  "reconciliations": [
    "NPS pages give over 170 nights/days versus over 200 freeze–thaw cycles. These are differently worded summaries, not one calibrated exposure series. No count is used by the model.",
    "Frost controls represent opportunities for water-dependent damage, not a count of thermodynamic cycles. Ice segregation research cautions against equating every freezing event with fracture.",
    "The old NPS description says dolomite cannot dissolve in weak carbonic acid. This absolute wording is not repeated; resistance is relative and material-specific.",
    "Bowers reports historical age uncertainty and nomenclature. The 2024 Parowan map discusses newer evidence near Bryce but is not a Bryce map. Public text avoids a precise age for each illustrated layer.",
    "The topographic models contain drawn bed colors. These cannot supply geologic contacts. Their outlines and interpretive intervals are deliberately shown as different evidence types.",
    "An agency’s regional erosion estimate cannot calibrate this model or forecast an individual landmark. No rate-to-year conversion is provided."
  ]
}