Geology and geomorphology of the Urema Graben with emphasis on the evolution of Lake Urema

Gorongosa by the sea: First Miocene fossil sites from the Urema Rift, central Mozambique, and their coastal paleoenvironmental and paleoecological contexts

“…Unconformably overlying Eocene marine limestones of the Cheringoma Formation on the Cheringoma Plateau are sedimentary successions that we herein refer to as Mazamba Formation. A review of the literature revealed inconsistencies in nomenclature and subdivision of this <130 m thick succession (cf., Real, 1966;Tinley, 1977;Lächelt, 2004;GTK Consortium, 2006;Steinbruch, 2010;Grantham et al, 2011;Pickford, 2013). Based on Real (1966), Tinley (1977) refers to the succession as Mazamba Formation (see also Steinbruch, 2010;Pickford, 2013), attributes it to a Mio-Pliocene age, and subdivides the formation into a basal member of red sandstone and quartzitic limestone, a central chert unit, and an upper quartzitic and conglomeratic Inhaminga sandstone member.…”

Combined electrical resistivity tomography and magnetic resonance sounding investigation of the surface-water/groundwater interaction in the Urema Graben, Mozambique

“…The location of L1 was selected to detect the change in the West flank from basement to rift-filling sediments known from the geological map and boreholes located in the national park's sanctuary (Steinbruch 2010). The L1 line crosses two seasonal rivers and the riverbeds are characterized by fine materials such as fine sand and clay (Steinbruch 2010) and L2 is part of the current floodplain, which was suspected to be a part of an ancient lake because of the presence of many abandoned river channels. L3 is perpendicular to the lake outflow and was chosen to study the variation of sediments at the transition between the floodplain and ancient Pungue River fan, while L4 was chosen to identify structural or geological features that may control the Urema out flow (Tinley 1977).…”

“…The local geology consists of four major parts: the Barue basement, the Gorongosa Mountain, the Urema Rift Valley and the Cheringoma Plateau forming the Urema catchment (Steinbruch 2010 ; Fig. 1).…”

“…The sediments consist of heavy montmorillonite-rich clays and leached sands with different grain sizes with coarser sediments along the flanks. The mean grain size generally decreases when moving from the edges of the Urema Rift Valley towards the centre; however, along the major drainages within the Graben there appear to be channels with coarser sediments (Steinbruch 2010). There also exists a Precambrian gneiss inlier in a tectonic window of the rift floor (Steinbruch 2010) and a thermal spring, Nhambita hot spring, occurring along the western rift border with a water temperature above 40°C (DNA 1987;Steinbruch and Merkel 2008).…”

“…Other streams discharging across the rift Fig. 1 Stratigraphical units of the Urema Catchment (from Steinbruch 2010) margin from the Barwe platform such as the Vunduzi, show a major decrease in stream valley size, suggesting reduction in stream flow, presumed to be due to groundwater recharge into the coarse clastic wedge at the rift margin. However, the significance of this finding for the recharge of Lake Urema has not been established, and there is no information on the hydrogeological link between the rift margin and the valley floor beneath Urema Lake.…”