The results of drilling during Ocean Drilling Program Leg 180 provide insights into fundamental processes of continental break-up, because rifting can be related to westward propagation of a spreading centre into continental crust. A generally north-south transect of holes was drilled across the Woodlark Rift on the uplifted northern rift margin on the Moresby Seamount (Sites 1114 and 1116), on the hanging wall of the low-angle (25–30°) extensional Moresby Detachment Fault (Sites 1108, 1110–1113 and 1117) and across the downflexed northern rift margin (Sites 1118, 1109 and 1115). The results, when placed in the regional tectonic context, document a history of Palaeogene ophiolite emplacement, followed by Miocene arc-related sedimentation. Regional uplift and emergence of the forearc area took place in Late Miocene time. Submergence to form the Woodlark Rift began in latest Miocene time, marked by widespread marine transgression and shallow-water deposition, accompanied by input of air-fall tephra and volcaniclastic sediments. During Pliocene time, deposition within the rift basin was dominated by deep-water turbidites, including high-density turbidites in the south. Strong extension along the north-dipping Moresby Detachment Fault was active during Pleistocene time, associated with uplift of the Moresby Seamount and shedding of fault-derived talus, mainly of meta-ophiolitic origin. During Pleistocene time, a carbonate platform was constructed to the NW, trapping clastic sediment and resulting in a switch to slower, more pelagic and hemipelagic deposition within the Woodlark Rift Basin. The marked change in rift basin configuration during Pleistocene time may relate to westward propagation of the Woodlark oceanic spreading centre at c. 2 Ma.

After a period of relative dormancy, the Lake Victoria Goldfields (LVG) in Tanzania, Kenya and Uganda have emerged as an important site for gold mining and exploration in Africa. The Neoarchaean greenstone belts of the LVG are composed mainly of "Nyanzian" metavolcanic sequences overlain by younger "Kavirondian" clastic metasedimentary strata. Intermediate to felsic plutonic rocks include local, older syn-volcanic bodies and an extensive suite of late, circa 2650-2640 Ma potassic (K)-granitoids, which substantially invade and disrupt the greenstone belts. Gold deposits are widely distributed but particularly concentrated in three belts: Sukumaland, Musoma-Mara and Busia-Kakamega. Many deposits are simply composed of quartz veins in shear zones and fractures in the Nyanzian host rocks (e.g. Bulyanhulu, Buck Reef and Rosterman). Buzwagi and Nyabirama are composed of quartz vein arrays within intrusions. Several are hosted by folded banded iron-formation (Geita, Golden Ridge, Tulawaka, and Nyanzaga). Nyanzaga, however, is a discordant pipe shaped stockwork containing dolomite, silica and sulphides as open-space fill in high level veins. Gokona-Nyabigena at North Mara is closely associated with porphyritic volcanic and sub-volcanic intrusive rocks and is noted for stockwork-disseminated mineralisation and extreme K-feldspar alteration. Field evidence points to a relatively late, syn-orogenic timing for the majority of the deposits irrespective of style. Most deposits were discovered and exploited in colonial times but many have been expanded considerably by modern exploration. Improved geological knowledge has resulted from this private sector exploration using high-resolution aeromagnetic, electromagnetic and radiometric surveys, followed up by regolith and outcrop mapping and systematic drill testing of large areas (rotary air blast (RAB), reverse circulation (RC), aircore and diamond drill core). Lithogeochemistry and geochronological studies have been carried out by several companies in support of their regional exploration programmes. The LVG is now considered mature from an exploration point of view, so future developments will require the investigation of vein deposits to greater depth and/or the discovery of additional examples of the lower grade stockwork-disseminated styles which may have been overlooked during the early rounds of exploration.

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