Abstract:
Because collision-related mountain chains form above sites of mantle
down welling (= mantle convection), contractional deformation in
general must be governed by the mechanism of underthrusting, mainly,
and the inner parts of mountains should correspond to crustal-scale
pop-up structures. In fact, convective cells and underthrusting are
the basis for a new understanding (termed Suction Tectonics) on
lithosphere deformation. The Brasília Belt (BB) is the most complex of
the three fold-and-thrust belts that constitute the Tocantins Province
of central Brazil, a Neoproterozoic orogen situated between the
Amazonian and São Francisco cratons. The Araguaia and Paraguay Belts
are the other two. The Araguaia-Brasilia Belt records the evolution of
a Meso-Neoproterozoic ocean and the collision between the Amazonian
and São Francisco paleo-continents, during the ~750-590 Ma Brasiliano
orogeny. The Paraguay Belt records the 620-510 Ma evolution of a
rift-oceanic basin opened within the Amazonian paleo-continent,
adjacent to the southern half of the BB. The results of a research
carried out in the last 15 years and focused on the operation of the
underthrusting mechanism in the BB are summarized, and a brief review
of the up-to-date literature supporting the new understanding on
lithosphere deformation is presented. Due to underthrusting, the inner
part of the BB evolved such as a crustal-scale pop-up structure, and
the evidence presented herein must be found in other collision-related
mountain chains on Earth.
Brief Biography of the Speaker:
PhD geologist, educator, born in Itabuna-BA, Brazil, 1947, son of José
Silva and Mary Alice H. D’el-Rey, married Irene Ordine Lopes H.
D’el-Rey, three children: Manuela, Alexandre, and Henrique O.L.H.
D’el-Rey. Diploma in Geology, University of Brasília (Brazil), 1971;
MSc in Geology, Federal University of Bahia (Brazil), 1984; PhD in
geology, Royal Holloway University London (UK), 1992; Post-doctor in
geology, Geological Survey of Finland (Finland), 2001. Biography
included in Marquis Who´s Who in Science and Engineering (2005, 2006,
2007-2008), and Who´s Who in the World (2007).
Associate Professor of structural geology and tectonics in the
Institute of Geosciences of the University of Brasília, since 1993,
where has been developing a research program focused on the controls
exerted by age- and scale-independent convection cells on the
deformation of the lithosphere and formation of tectonic features such
as mountain belts, basins, plateaus, with special attention on the
tectonic evolution of the Neoproterozoic fold belts that surround the
São Francisco Craton, Brazil. Scientific publications include 64
pieces or work, being 34 full papers (25 in indexed periodicals, 9 in
congresses). Large working experience in mine geology and on the
structural controls of ore deposits, with special achievements in the
detailed study of highly deformed ore deposits of copper, gold,
emerald, and base sulfides, in Brazil and in Canada.
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