Title: On the discovery of ferromanganese nodules in the World Ocean

Authors: I. M. Belkin, P. S. Andersson & J. Langhof

Journal & Year: Deep-Sea Research Part I, 2021

BLUF: Ferromanganese nodules were definitively discovered by the HMS Challenger expedition in 1873, not by the earlier Swedish Sofia expedition as has often been claimed. In this 2021 study published in Deep-Sea Research Part I, Belkin, Andersson, and Langhof critically examine historical expedition records and chemical analyses to refute the counterclaim attributing the discovery to Nordenskiöld’s 1868 Arctic voyage. The authors confirm that the only valid manganese-rich sample attributed to Nordenskiöld was actually collected a decade later by the Vega expedition. Their investigation not only corrects a longstanding historical error, but also reinforces the legitimacy of Challenger’s early seafloor findings — bolstering confidence in the foundational geoscientific data that underpin today’s deep-sea mineral exploration. For the deep-sea mining sector, this clarity strengthens trust in the historical record of resource discovery and affirms the early recognition of ferromanganese nodules as viable mineral assets.

Ferromanganese nodules — rounded, metal-rich concretions found on abyssal plains — are one of the three principal mineral resource types currently targeted for deep-sea mining.

They were long believed to have been discovered by the Challenger expedition (1872 - 1876), a landmark voyage in the history of oceanography.

However, since 1978, a counter-narrative has circulated, suggesting that nodules were first found in 1868 by the Sofia expedition led by Swedish explorer A.E. Nordenskiöld. This claim has been widely cited in scientific and public discourse.

Belkin et al. set out to resolve this claim through a detailed review of expedition records, chemical analyses, and navigational charts.

Their analysis begins with a precise recounting of the Challenger’s dredging operations: the first crust sample was recovered on 18 February 1873 (Station 3), and the first clearly recognized manganese nodules were retrieved on 7 March 1873 (Station 16) in the North Atlantic.

These events are clearly marked on a reprinted historical map from the expedition (Fig. 1, p. 3), showing the precise locations of these milestone discoveries along the Challenger's trans-Atlantic route.

Further strengthening their case, the authors use modern high-resolution bathymetric data to validate the site of the first iron-manganese (Fe-Mn) crust discovery.

They demonstrate that Challenger Station 3, where crusts were first retrieved, corresponds exactly to a steep ridge on The Paps Seamount, a site recently confirmed as a prime location for ferromanganese crust formation (Fig. 3, p. 4).

This correlation between 19th-century sampling and modern seafloor morphology not only substantiates the original discovery but also underscores the geological continuity of resource-rich sites across time.

In contrast, the 1868 Sofia expedition never approached the Kara Sea, and the sample long believed to be the earliest nodule was actually collected a decade later during the Vega expedition in 1878.

The confusion stems from a poorly cited Swedish-language report that grouped together samples from both voyages. Once separated, the timeline makes clear that Challenger predates Vega by five and a half years — a meaningful distinction in the chronology of marine geology.

The alternative claim traces to a report by Swedish chemist Gustaf Lindström, who published manganese content data in 1884 from two sets of samples: one from the Sofia expedition (1868), and another from the Vega expedition (1878 - 1880).

The confusion arose because Lindström’s brief, Swedish-language pamphlet grouped all 14 samples together, and later authors mistakenly attributed the high-manganese sample (#3) to the Sofia voyage.

In fact, as Belkin et al. show using navigational maps (Fig. 4, p. 5), the Sofia never entered the Kara Sea — the location of the manganese-rich sample. The sample in question was clearly collected by Vega in August 1878, ten years later.

This point is crucial because Challenger’s confirmed dredges predate Vega by over five years. The authors bolster this conclusion with geographic evidence: high-resolution bathymetry confirms the Challenger’s Station 3 took place on the steep flanks of the Paps Seamount, a known site for ferromanganese crust formation, reinforcing the scientific significance of the 1873 recovery.

While the primary contribution of this paper is historical, the implications extend directly to modern deep-sea resource development. Ferromanganese nodules and crusts are now recognized as economically significant sources of battery metals and technology-critical elements.

Ensuring the provenance and reliability of early data is not just a matter of academic accuracy — it directly informs environmental baselines, mineral system models, and legal frameworks for seafloor resource claims. For stakeholders in the mining industry, this study reaffirms the credibility of Challenger's pioneering work as a valid starting point for global assessments.

The geological samples, locations, and mineral analyses provided by the Challenger remain among the most rigorously documented early records, forming a foundation for subsequent mapping and exploration.

Furthermore, this case illustrates the value of revisiting primary data in an era where digitization and geospatial analysis allow for deeper verification of historical claims. It also serves as a reminder that institutional memory — when passed through decades of citations without critical re-evaluation — can sometimes ossify around inaccuracies.