Die geologische Entwicklung von Süd-Mozambique seit der ...

seit der U n te rk re id e und die A m m o n ite n -F a u n a usw. 259
ments rcst on the Karroo volcanics. Similar conditions prevail in the Save River region,
somc 500 km to the north. This mcans, that north of the Incomati River an uplift
(Limpopo—Save uplift) scems to have existed for a long period, separating the S outhern
trough from the Zambezi trough. It was transgressed not earlier than in Maestrichtian
time.
Ccnomanian
Lower and Middle Ccnomanian strata along the Coane River in the south yielded
shallow-watcr faunas corresponding to the saxbii- and the rAoiomdgcttse-assemblages
of S o u t h e r n England. Lithologically, the sediments resemble those of the Aptian and
Albian.
Upper Cretaceous
A regressive cvcle with a major unconformity followed in late Ccnomanian times.
Corresponding to Aptian—Albian conditions the Limpopo—Save uplift continued, as
evidenced bv an increasing hiatus from south to north. An uninterrupted Sedim entation
is onlv known from boreholes in the deeper parts of the basin farther to the east.
K e n n e d y & K l i n g e r (1971) confirm a hiatus from the Upper Cenomanian to Coniacian
in Zululand. In S outhern Mozambique in the area of the Maputo River, Upper
Santonian to Lower Campanian transgressed. In the Incomati River region transgression
occurred in the late Campanian and Maestrichtian. Sediments of nearly the same age
(Grudja Formation) have been traced north of the Limpopo—Save uplift along the Buzi
River, extending northwards to the Zambezi River. In the area of the uplift the marine
facies grades into a lagoonal environment with dwarfed faunas and local cvaporitic
horizons. It fin allv ends with fluviatile-continental sediments.
In the south these Continental sediments are restrictcd to small areas (Boane sandstone).
Probably fluviatile channel sediments, they rarely exceed a thickness of ICO m.
In contrast, the Continental deposits of the Zambezi trough attain more than 2500 m.
The bulk of this sequence (Sena Formation) consists of badly sorted, cross-bcdded,
reddish arkoses, sandstones. and conglomerates. The age of the base of these Sena sandstones
is not preciselv defined. The presence of rhvolitic intrusions in the basal parts
points to an at least Lower Cretaceous. more probably Upper Jurassic age. They are
overlain by the marine sediments of the Campanian—Maestrichtian Grudja Formation.
Marine Turon is only represented eastwards in the deeper parts of the basin, where
a continuous succession of marine sediments can be presumed to have been deposited
during late Cretaceous to earlv Tertiary. In the marginal parts of the basin the
higher Maestrichtian and Lower Palcocene is lacking and Middle Palcocenc transgressed
over Maestrichtian.
Lower Tertiary
The Palcocene shows a reduced thickness. The fine-grained silty sandstones of
Mangulane vielded a well preserved niicrofauna of the mid-Paleoccne arignl