Duho Formation
Middle Miocene geologic formation in South Korea
The Duho Formation (Korean: 두호층; Hanja: 斗湖層; RR: Duho-cheung) is a middle Miocene geological formation in Pohang, South Korea. This formation is deposited in a deep marine environment and is roughly dated to around 15 to 12 million years ago based on various analyses. It is the uppermost unit of the Yeonil Group of Pohang Basin and mainly composed of yellow-brown to dark gray mudstones.
Geology
The deposition of the Pohang Basin began some time after 21.89 to 21.68 million years ago, corresponding to the Early Miocene, based on zircon U-Pb dating. This deep-marine basin was probably produced by rapid subsidence around 17 million years ago, following the abrupt ending of the strike-slip deformation and volcanic activity, and experienced tectonic inactivity for 5 to 7 million years until the crustal uplift in southeastern Korea around 10 million years ago which caused the sedimentation to cease. The basin was likely a pelagic zone around 17.6 to 11.5 million years ago based on biostratigraphy analysis.
The intrusive basalt of the Yeonil Group from the southern part of the basin is dated to the lower Middle Miocene around 15.16 to 14.82 million years ago based on K-Ar dating, which implies the evolution of back-arc basin in the seas of southeastern Korea, followed by the tectonic inversion which changed the geodynamic setting and basaltic magma composition. Paleomagnetic dating (analysis of the sediments' ancient magnetic fields) of the Duho Formation yielded the age estimate ranging from 14.7 to 11.6 million years ago. The age estimate of the Yeonil Group based on the same technique is around 17.3 to 11.3 million years ago for the lower and upper part respectively with a reliable pole position of 15 million years ago, while biostratigraphy analysis indicated that the age of the Duho Formation likely ranged from 14 to 12 million years ago. It is probably not younger than 11.95 million years ago based on the radiolarians recovered from the formation.
“Duho Formation” enters the record as middle Miocene geologic formation in South Korea. Crown Archives preserves that source wording while asking what Duho, Formation and Middle can confirm, complicate or overturn.
Why this record matters
“Duho Formation” is worth following because a concise public description often conceals a longer documentary argument. Here, Duho, Formation and Middle provides the most credible route into that argument.
The citation trail is more important than the brevity of the summary: it shows where individual claims can be examined in context. The source revision retrieved here is dated Sep 20, 2026. The linked authority identifier is Q133281420. Authority coordinates are 36.000, 129.200. None of the 1 selected statements returned an explicit reference.
Overview language is designed for orientation and should not be treated as a substitute for the evidence cited beneath it. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Use the entry as an orientation point, then follow its citations and revision history. Names, dates and institutional relationships should be checked against the original record.
- Subject orientation
- Search vocabulary
- Locating named sources
The closest primary source, responsible institution and strongest cited specialist reference.
Three-step research path
- Establish the record: confirm the title “Duho Formation”, its source revision and the description used here.
- Expand the search: follow Duho Formation primary sources, Duho Formation archive and Duho research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “Duho Formation”?
- What terminology or title could unlock a more precise catalogue search?
- Which institution is responsible for the underlying evidence?
Search terms from this dossier
This entry incorporates text from “Duho Formation” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.