Geology and Intrusion-Related Affinity of the Morila Gold Mine, Southeast Mali

A Review of Gold Mineralization in Mali

“…The adjacent basins, from west to east, are referred to as the Siguri basin (located mainly in Guinea), the Mandiela basin, and the Kadiola basin. This area hosts some major gold deposits, including those exploited at the Morila, Kalana, and Syama mines (Milési et al 1992;Olson et al 1992;McFarlane et al 2011). Birimian rocks were deformed and metamorphosed during the Eburnean orogeny around 2.1-2.0 Ga.…”

“…The general characteristics of orogenic gold deposits are summarized in Groves et al (1998) and Ridley and Diamond (2000). Recently, a more complex Birimian gold metallogenesis has been recognised, with new styles of gold mineralization documented such as reduced intrusion-related gold systems and gold skarn deposits (McFarlane et al 2011;Ouattara et al 2014). This review documents the genesis of both orogenic gold and reduced intrusion-relation gold mineralization in Mali, with emphasis on the country's four largest ore bodies: Loulo, Gounkoto, Sadiola, and Morila.…”

“…Discussion of gold mineralization in the West Mali gold belt is a synthesis of three recent studies (Lawrence et al 2013a, b;Masurel et al in press). Synopsis of the Morila deposit in southern Mali relies on reports by Hammond et al (2011) and McFarlane et al (2011), together with data from two MSc theses by Quick (1999) and King (2012).…”

“…Subtle lithologic variations occur locally with interbeds composed of finer-grained meta-pelitic rocks and meta-basalts. Within the siliciclastic rocks, beds have sharp bases, grade upwards, and show pronounced soft-sediment deformation features typical of turbidite systems such as flame structures and load clasts (McFarlane et al 2011). Sedimentary rocks in the vicinity of Morila have contact metamorphic assemblages typical of amphibolite-facies conditions, including abundant hornblende in the meta-basalts and cordierite and andalusite preserved in the more pelitic rocks.…”

“…Sedimentary rocks in the vicinity of Morila have contact metamorphic assemblages typical of amphibolite-facies conditions, including abundant hornblende in the meta-basalts and cordierite and andalusite preserved in the more pelitic rocks. Several intrusions are emplaced into the meta-sedimentary sequence of the Morila permit area (McFarlane et al 2011). The oldest of these are thin (5-10 m), porphyritic mafic to intermediate-composition hypabyssal dikes for which geochemical data suggest a continental margin setting.…”