The Fragmentation of Helcar: A Paratethyan Model for Rhûn, Núrnen and the Dead Marshes

Authors

• Federico Manzoni, independent researcherFollow

Abstract

This work proposes a conjectural paleogeographic model linking the Sea of Rhûn, Núrnen and the Dead Marshes to the former Sea of Helcar. Beginning from Christopher Tolkien's suggestion that Rhûn may represent Helcar ``vastly shrunken,'' the study combines textual evidence, the Ambarkanta, Fonstad's cartographic reconstructions, and terrestrial analogues drawn from the evolution of the Paratethys, the Messinian Salinity Crisis and other endorheic basins. Helcar is interpreted not merely as an isolated body of deep water but as the centre of a broader hydrological province subsequently partitioned by relief change, sedimentary infilling, basin isolation and drainage reorganization. Within this model, Rhûn survives as a north-eastern, river-supported remnant sustained by the Celduin; Núrnen develops as a southern closed basin in which long residence time and evaporation plausibly concentrate dissolved salts; and the Dead Marshes occupy a western lowland whose inherited lacustrine substrate favoured later wetland expansion across Dagorlad. Scale-based measurements anchored on a control point in the northern Blue Mountains indicate that the positions and spatial envelope of the three later features are dimensionally compatible with the mapped extent of Helcar, provided that its marginal hydrological zone extended beyond the area represented as permanent deep water. The model does not claim to recover Tolkien's intended geology or to establish an exact cartographic superposition. Rather, it offers a reconstruction showing how scientific analogy can explain the physical coherence of Tolkien's changing geography without mistaking that coherence for canon.

Recommended Citation

Manzoni, Federico (2026) "The Fragmentation of Helcar: A Paratethyan Model for Rhûn, Núrnen and the Dead Marshes," Journal of Tolkien Research: Vol. 24: Iss. 3, Article 5.
Available at: https://scholar.valpo.edu/journaloftolkienresearch/vol24/iss3/5