Marine Placer Deposits

Marine Placer Deposits comprise detrital heavy metallic minerals and gemstones, eroded from, usually igneous, source rocks on land and transported to sea, mostly by rivers. Thereby, placer deposits are concentrated by water motions (waves, tides, currents).

The most important of these minerals, from an economical aspect, are: cassiterite (tin), ilmenite and rutile (titanium), zircon (zirconium), chromite (chromium), monazite (thorium), magnetite (iron), gold; the principle gemstone is diamond (Harben & Bates 1990). According to Daesslé and Fischer (2013) about 75% of the world’s tin, 11% of gold, and 13% of platinum are extracted from placers (Baker et al. 2014).

Figure 1
Figure 1

Montalvo Beach magnetite-rich placer deposit, Galician coast . Source: Pérez et al. 2008.

Figure 1
Figure 1

Montalvo Beach magnetite-rich placer deposit, Galician coast . Source: Pérez et al. 2008.

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The potential for the occurrence of placer deposits within the sedimentary accumulations of the continental shelf is significant. However, current knowledge is sparse, mostly limited to seafloor deposits on shallow waters which are more accessible for exploration. Thus, the need for an integrated research approach on the European seas is imminent, given the present-day RM (raw materials) demands and exploitation technological advances, towards sustainable use and management of the subsurface.

Figure 2
Figure 2

Olivine-rich sand grains recovered in marine placer deposits from Big Island (Hawaii). Photo: IGME

Figure 3
Figure 3

SEM images of placer minerals from the Germany (image a), Mongolia, Nepal and Cyprus (images e and f). Source: DOI: 10.1016/j.sedgeo.2006.11.002.

Figure 2
Figure 2

Olivine-rich sand grains recovered in marine placer deposits from Big Island (Hawaii). Photo: IGME

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