JJEES Volume 1, Number 1, Mar. 2008 ISSN 1995-6681 Pages 45 -52 Jordan Journal of Earth and Environmental Sciences Rare Earth Elements Geochemistry of the Cambrian Shallow Marine Manganese Deposit at Wadi Dana, South Jordan Tayel El-Hasan a, * , Ahmad Al-Malabeh b , Kosei Komuro c a Faculty of Science, Mu’tah University, 61710, Al-Karak – Jordan b Dept. of Earth and Environmental Sciences, Hashemite University, Zarqa, Jordan c Institute of Geoscience, University of Tsukuba, 1-1 Ten’nodai, Tsukuba, Ibaraki, 305-8571, Japan Abstract The Cambrian manganese deposits of Wadi Dana were investigated for their REE geochemistry, contents and patterns. Compared with other manganese ore types the studied ore is REE depleted. However, such depletion can be applied to the high-grade ores, while the low-grade ores bears higher REE due to the detrital contribution. The horizontal variation throughout the basin is insignificant, while, the vertical variation is pronounced. Vertically. The ∑REE and many individual REE’s are increasing upwards except for Yb and Eu. Moreover, Ce/∑REE and Eu/Sm vertical behavior shows inverse relationship that reflects the increase of oxic diagenetic conditions upwards. The normalization pattern shows that the ore exhibits a high positive Eu and no or small positive Ce anomalies. The REE pattern and content is comparable to similar worldwide diagenetic manganese ores. © 2008 Jordan Journal of Earth and Environmental Sciences. All rights reserved Keywords: REE; Spatial variation; Mobilization; Diagenesis; Ce and Eu-anomalies; * Corresponding author. e-mail: tayel@mutah.edu.jo 1. Introduction Manganese deposits were known to form since the Archean and are being formed at the present day. It formed in various environments e.g. lakes, internal seas, pelagic, archipelago, shallow marine, deep marine, as well as terrestrial mineralization. This is due to the fact that manganese can be formed by hydrothermal, sedimentary, and supergene processes. Manganese diversity in time and environment of deposition can be of great importance for better understanding of the geochemical processes responsible for its deposition. Furthermore, it can contribute to the on going investigation of the Earth's evolution history, and help in explaining the worldwide phenomena such as the Banded Iron Formation (BIF) (Kimberely, 1989). Huge deposits were discovered around the world (e.g. Nikopol of Ukrania, and at Chiatura of Georgia, and the Groote Eylandt deposit of Northern Australia, (Varentsov, 1982; and Frakes & Bolton, 1992), Hokkaido manganese deposits of Japan (Miura and Hariya 1997) and Thrace deposits of Turkey (Ozturk and Frakes 1995) and Orissa, manganese deposits of India (Nicholson et al. 1997). The REE geochemistry as a tool and tracer for marine environment and sedimentary processes has been used by many authors (e.g. Elderfield et al. 1981; De Baar et al. 1983; Alpin, 1984; Klinkhammer et al. 1983; Michard et al. 1983; Calvert et al. 1987; Glasby et al. 1987; De Baar et al. 1988 and Rolland et al. 2003). Slight change in REE contents or their patterns may reflect a change in redox potential (Piper, 1974; Elderfield, 1988; and De Carlo, 1991), and might be due to the change in sorption properties of solid phases (Alpin, 1984; Byrne & Kim 1990; De Carlo & Koeppenkastrop 1990; and Koeppenkastrop & De Carlo 1990). Also it can be caused by complexation with major anions of seawater (Byrne & Kim 1990; Cantrell & Byrne 1987; and De Carlo & MaMurtry 1992). Hence the REE mobility is controlled mainly by the redox potential of the environment, therefore REE patterns can be used in tracing out the post- depositional processes (i.e. diagenesis) (Ozturk and Frakes 1995; De Carlo, 1991; and Dymon et al. 1984). Dubinin & Volkov, (1986) found that low Ce/La ratio was found to be indicative for ore deposition by direct precipitation or adsorption from seawater. Moreover, Glasby et al. (1987) found Ce/La ratio a useful redox indicator, when they noticed the increasing trend in Ce/La ratio from the SW Pacific towards the equatorial Pacific; due to the passage of the Antarctic Bottom Water. Ponater (1988) have measured a higher Ce/La ratio (2.5-3.2) in the Urkut manganese deposit of Hungary and used it as an indicator for a terrigenous source of REE, which causes also a