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Chapter 5
Parameters And Standards for Assessing
Sedimentary and Manganese Nodule
Facies in a Potential Mining Area in the
Peru Basin
Dr. Michael Wiedicke-Hombach, Marine Geologist, Bundesanstalt
für Geowissenschaften und Rohstoffe (BGR), Germany
This paper focuses on geoscientific results of research undertaken
in the Peru Basin. The Peru Basin, in the southern Central Pacific Ocean, is
a potential future mining area for manganese nodules. Several
interdisciplinary cruises with the German RV Sonne were conducted in the
area during the past 10-12 years, covering biology, sedimentology,
geochemistry, soil mechanics and other disciplines. The objectives of these
projects included a proper description of the current environmental
situation at the seafloor and a definition of potential impact-sensitive
parameters, well in advance of any deep-sea mining activity. The results
presented here stem from two survey areas: (1) the Disturbance
Recolonisation (DISCOL) project area at about 88 degrees 30 minutes west
longitude / 7° south latitude and (2) an area about 230 kilometres further
west (Sediperu area).
In this article, I will present a selection of those parameters, which
turned out to show an often-unexpected variability and, thus, are important
for defining the baseline situation. I will concentrate on the geological
aspects; results on benthic biology are covered by a contribution of Gerd
Schriever (chapter 15 below). Details of the results presented here are
covered in a special volume of Deep-Sea Research I I 1 .
1. Large-Scale Parameters
1.1. Bathymetry
Bathymetric mapping in the survey areas of the Peru Basin
exhibited abyssal hill topography with water depth often between 4000 and
4400 metres. However, some hills were higher and one huge seamount
towered about 2 km above the general seafloor level. A general
topographic pattern became obvious: north-south aligned, elongated 200-
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