P.M. Hurley
W.H. Pinson
H.W. Fairbairn
Norman Herz
1961
<p><span>Potassium-argon determinations on micas from Precambrian granitic rocks of the Quadrilátero Ferrífero, Minas Gerais, Brazil, suggest three ages of intrusion: 2400 m.y. determined from gneiss within the Bação complex; 1350 m.y. from rocks in the northern </span><span class="ScopusTermHighlight">part</span><span> of the Bação complex and also in </span><span class="ScopusTermHighlight">a</span><span> region 7 km north of nearest known Minas series metasedimentary rocks (Late Precambrian </span><span class="ScopusTermHighlight">age</span><span>); and 450-550 m.y. The last has been determined from (1) gneiss of the eastern </span><span class="ScopusTermHighlight">part</span><span> of the area, (2) granitized beds of the Minas series, and (3) granite between Minas beds and the 1350 m.y. granite in the western </span><span class="ScopusTermHighlight">part</span><span> of the area. Other ages, ranging between 595 and 1080 m.y., may represent the effects of </span><span class="ScopusTermHighlight">a</span><span> younger metamorphism on older granitic rocks that are found between the peripheral area of the 1350 m.y. granites and Minas metasedimentary rocks. </span></p>
application/pdf
10.1130/0016-7606(1961)72[1111:AMFAPO]2.0.CO;2
en
Geological Society of America
Age measurements from a part of the Brazilian shield
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