Episodic rapakivi magmatism due to distal orogenesis? Correlation of 1.69 - 1.50 Ga orogenic and inboard, "anorogenic" events in the Baltic Shield
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Episodic rapakivi magmatism due to distal orogenesis? Correlation of 1.69 - 1.50 Ga orogenic and inboard, "anorogenic" events in the Baltic Shield. / Åhäll, (Karl-Inge; Connelly, James N.; Brewer, Tim S.
In: Geology, Vol. 28, No. 9, 2000, p. 823-826.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Episodic rapakivi magmatism due to distal orogenesis?
T2 - Correlation of 1.69 - 1.50 Ga orogenic and inboard, "anorogenic" events in the Baltic Shield
AU - Åhäll, (Karl-Inge
AU - Connelly, James N.
AU - Brewer, Tim S.
PY - 2000
Y1 - 2000
N2 - The temporal overlap of 1.69-1.55 Ga westward growth of the Baltic Shield and voluminous, episodic, 1.65-1.50 Ga rapakivi magmatism in the Svecofennian domain to the east has long been recognized. New U-Pb data from southwest Sweden indicate that this westward growth occurred in at least three distinct stages involving convergent-margin magmatism (Gothian orogenesis) at 1.69-1.65, 1.62-1.58, and 1.56-1.55 Ga. This improved resolution along the margin reveals an interesting temporal correlation between these events and the intracratonic rapakivi magmatism. Each stage of convergent-margin magmatism was echoed by a phase of bimodal rapakivi magmatism at 1.65-1.62, 1.58-1.56, and 1.55-1.50 Ga. In addition to this temporal correlation, rapakivisuites form distinct north-trending arrays that are subparallel to, but 500-1500 km east of, the active margin. These temporal and spatial links suggest that recurring subduction along oceanward-stepping zones provided first-order control(s) on episodic mantle melting and consequent bimodal rapakivi magmatism in distal, inboard settings. At the very least, emerging constraints from Baltica do not support previous, purely anorogenic models for the 1.65-1.50 Ga rapakivi magmatism or models that singularly implicate lingering effects from the preceding Svecofennian orogeny.
AB - The temporal overlap of 1.69-1.55 Ga westward growth of the Baltic Shield and voluminous, episodic, 1.65-1.50 Ga rapakivi magmatism in the Svecofennian domain to the east has long been recognized. New U-Pb data from southwest Sweden indicate that this westward growth occurred in at least three distinct stages involving convergent-margin magmatism (Gothian orogenesis) at 1.69-1.65, 1.62-1.58, and 1.56-1.55 Ga. This improved resolution along the margin reveals an interesting temporal correlation between these events and the intracratonic rapakivi magmatism. Each stage of convergent-margin magmatism was echoed by a phase of bimodal rapakivi magmatism at 1.65-1.62, 1.58-1.56, and 1.55-1.50 Ga. In addition to this temporal correlation, rapakivisuites form distinct north-trending arrays that are subparallel to, but 500-1500 km east of, the active margin. These temporal and spatial links suggest that recurring subduction along oceanward-stepping zones provided first-order control(s) on episodic mantle melting and consequent bimodal rapakivi magmatism in distal, inboard settings. At the very least, emerging constraints from Baltica do not support previous, purely anorogenic models for the 1.65-1.50 Ga rapakivi magmatism or models that singularly implicate lingering effects from the preceding Svecofennian orogeny.
KW - Anorogenic magmatism
KW - Baltic Shield
KW - Orogenic growth
KW - Proterozoic
KW - Rapakivi granites
U2 - 10.1130/0091-7613(2000)28<823:ERMDTD>2.0.CO;2
DO - 10.1130/0091-7613(2000)28<823:ERMDTD>2.0.CO;2
M3 - Journal article
AN - SCOPUS:84879882263
VL - 28
SP - 823
EP - 826
JO - Geology
JF - Geology
SN - 0091-7613
IS - 9
ER -
ID: 334860757