Evolution of metallogeny of granitic pegmatites associated with orogens throughout geological time
A. V. Tkachev
10.6084/m9.figshare.3454913.v1
https://geolsoc.figshare.com/articles/journal_contribution/Evolution_of_metallogeny_of_granitic_pegmatites_associated_with_orogens_throughout_geological_time/3454913
<p>Since <em>c.</em> 3.1 Ga, pegmatite mineral deposits in orogenic areas have been formed throughout geological time in pulses, alternating with
total absence of generating activity. The higher activity peaks of 2.65–2.60, 1.90–1.85, 1.00–0.95, and 0.30–0.25 Ga suggest
a quasi-regular periodicity of 0.8±0.1 Ga. This series is dominated by pegmatites of Laurasian blocks. The lower peaks at
2.85–2.80, 2.10–2.05, 1.20–1.15, and the higher one at 0.55–0.50 make up another series represented by pegmatites in Gondwanan
blocks only. Each pegmatite class is characterized by a life cycle of its own, from inception to peak through to decline and
eventual extinction. The longest cycle is recorded for the rare-metal class deposits, which first appeared in the Mesoarchaean
and persisted through all the later eras, deteriorating gradually after the Early Precambrian. Muscovite pegmatites first
appeared in the Palaeoproterozoic and reached the end of their life cycle at the Palaeozoic–Mesozoic boundary. The miarolitic
class of pegmatite deposits in orogenic setting first came into being in the terminal Mesoproterozoic and dominated the pegmatite
metallogeny of many Phanerozoic belts. The evolution of the pegmatite classes was controlled by the general cooling of the
Earth and by associated changes in the tectonics of the lithosphere.
</p>
2016-06-21 12:26:22
cooling
periodicity
series
pulse
Precambrian
Muscovite pegmatites
terminal Mesoproterozoic
3.1 Ga
decline
pegmatite mineral deposits
pegmatite metallogeny
tectonic
pegmatite deposits
absence
granitic pegmatites
extinction
Phanerozoic belts
miarolitic class
Laurasian blocks
lithosphere
Palaeoproterozoic
Mesoarchaean
inception
Gondwanan blocks
evolution
pegmatite class
pegmatite classes
life cycle
activity peaks
orogenic areas
Palaeozoic
Geology