Intermittent 1630-1220 Ma magmatism in central Mazatzal Province; new geochronologic piercing points and some tectonic implications

The northern Burro Mountains in southwestern New Mexico reveal three distinct, intimately juxtaposed Mesoproterozoic magmatic suites in southern Laurentia. At 1633 Ma, the newly formed Mazatzal crust was intruded by tholeiitic diabase with a depleted-mantle-type Nd isotope composition but with enric...

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Bibliographic Details
Published in:Geology (Boulder) 2003-04, Vol.31 (4), p.335-338
Main Authors: Ramo, O. Tapani, McLemore, Virginia T, Hamilton, Michael A, Kosunen, Paula J, Heizler, Matt, Haapala, Ilmari
Format: Article
Language:English
Subjects:
A-type granites
absolute age
anorthosite
Burro Mountains
dates
diabase
experimental studies
faults
Geochronology
Geology
granites
Grant County New Mexico
IGCP
igneous rocks
inclusions
ion probe data
isotope ratios
isotopes
lamprophyres
Laurentia
Lava
magmatism
mass spectra
Mazatzal Orogeny
metals
metamorphic rocks
metasomatism
minette
Nd-144/Nd-143
neodymium
nesosilicates
New Mexico
orthosilicates
Paleoproterozoic
Plate tectonics
plutonic rocks
Precambrian
Proterozoic
rapakivi
rare earths
Redrock New Mexico
SHRIMP data
silicates
southwestern New Mexico
spectra
stable isotopes
structural controls
Structural geology
tectonics
tholeiitic composition
transcurrent faults
U/Pb
underplating
United States
upper Precambrian
xenoliths
zircon
zircon group
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Summary:The northern Burro Mountains in southwestern New Mexico reveal three distinct, intimately juxtaposed Mesoproterozoic magmatic suites in southern Laurentia. At 1633 Ma, the newly formed Mazatzal crust was intruded by tholeiitic diabase with a depleted-mantle-type Nd isotope composition but with enriched incompatible trace element abundances. A potassic granite-minette suite was emplaced ca. 1460 Ma, and a tholeiitic A-type granite-anorthosite suite intruded ca. 1225-1220 Ma. The diabase-minette-anorthosite sequence and the associated silicic rocks record dominantly juvenile additions to the cratonic margin and imply subcontinental enrichment events ca. 1650 Ma (accretion), prior to 1460 Ma (potassic metasomatism), and ca. 1220 Ma (magmatic underplating). The latter two may have been controlled by a major transcurrent structure along the south margin of Laurentia.
ISSN:0091-7613
1943-2682
DOI:10.1130/0091-7613(2003)031<0335:IMMICM>2.0.CO;2