scholarly journals Compositional changes due to hydrothermal alteration and mixing combined with differentiation and accumulation of igneous rocks from northern part of Mt. Shaku-dake, northern Kyushu, southwest Japan

2021 ◽  
Vol 127 (10) ◽  
pp. 605-619
Author(s):  
Keisuke Eshima
Keyword(s):  
Hydrothermal Alteration ◽  
Igneous Rocks ◽  
Southwest Japan ◽  
Compositional Changes

Isotopic age determinations on clay minerals from lavas and tuffs of the Derbyshire orefield

1972 ◽  
Vol 109 (6) ◽  
pp. 501-512 ◽  
Author(s):  
P. R. Ineson ◽  
J. G. Mitchell
Keyword(s):  
Clay Minerals ◽  
Hydrothermal Alteration ◽  
Igneous Rocks ◽  
The Other ◽  
Mineral Deposits ◽  
Isotopic Age ◽  
Hydrothermal Mineralization ◽  
Pumice Tuff ◽  
Southern Section ◽  
Age Determinations

SummaryEpisodic hydrothermal mineralization has previously been recognized in the northern section of the Pennine orefield. Igneous rocks from the southern section (the Derbyshire orefield) have yielded isotopic ages, some of which are thought to represent ages of hydrothermal metasomatism (deuteric or subsequent). In order to ascertain whether epicyclic hydrothermal events gave rise to the Derbyshire mineral deposits, samples of highly altered doleritic lava and pumice tuff were collected adjacent to areas of mineralization. Clay-mineral concentrates from 34 samples were dated by the potassium–argon method. The conclusions drawn from these analyses support a hypothesis of repeated hydrothermal alteration of the clay minerals, reflecting at least two episodes of mineralization, one about 270 m.y., the other about 235 m.y. The geo-chronological significance of these and other results is considered.

Igneous rocks and hydrothermal alteration at Bingham, Utah

1969 ◽  
Vol 64 (1) ◽  
pp. 34-49 ◽  
Author(s):  
R. Eldon Bray
Keyword(s):  
Hydrothermal Alteration ◽  
Igneous Rocks

scholarly journals Age relations and petrology of alkalic igneous rocks from Oki Dozen, Southwest Japan.

1997 ◽  
Vol 31 (3) ◽  
pp. 135-154 ◽  
Author(s):  
Paul A. Morris ◽  
Tetsumaru Itaya ◽  
Shigeru Iizumi ◽  
Hiroo Kagami ◽  
R. John Watling ◽  
...  
Keyword(s):  
Igneous Rocks ◽  
Southwest Japan ◽  
Age Relations

scholarly journals High Al contents in quartz and hydrothermal alteration of the "Roseki" deposits in the Mitsuishi district, Southwest Japan.

2002 ◽  
Vol 97 (4) ◽  
pp. 168-176
Author(s):  
Hidetomo HONGU ◽  
Akira YOSHIASA ◽  
Masanori KUROSAWA ◽  
Makio OHKAWA ◽  
Ryuji KITAGAWA ◽  
...  
Keyword(s):  
Hydrothermal Alteration ◽  
Southwest Japan

Early Carboniferous deformation and mineralization in the Cobequid shear zone, Nova Scotia: an 40Ar/39Ar geochronology study

2004 ◽  
Vol 41 (12) ◽  
pp. 1425-1436 ◽  
Author(s):  
Georgia Pe-Piper ◽  
Peter H Reynolds ◽  
Joe Nearing ◽  
David JW Piper
Keyword(s):  
Nova Scotia ◽  
Shear Zone ◽  
Hydrothermal Alteration ◽  
Early Carboniferous ◽  
Fault Zones ◽  
Igneous Rocks ◽  
Pluton Emplacement ◽  
History Of ◽  
Temperature Shear ◽  
Age Determinations

Latest Devonian to Early Carboniferous igneous rocks along the Cobequid shear zone of central Nova Scotia record a complex history of intrusion, volcanism, deformation, and hydrothermal alteration. Twenty new 40Ar/39Ar age determinations have been made on biotite and hornblende separates from rocks that constrain these events. The mafic plutons of the Cobequid shear zone are synchronous with the previously dated granitoid plutons (363–355 ± 4 Ma), with the exception of the younger Folly Lake gabbro (355–350 ± 4 Ma). High temperature shear deformation continued along the Cobequid shear zone during this entire period of pluton emplacement. Several samples from mylonitic and hydrothermally altered rocks with dates ca. 340 Ma indicate renewed movement along the Cobequid shear zone at this time, accompanied by minor magmatism. Younger ∼330–320 Ma ages reflect final movement along the Rockland Brook fault resulting in mid-Namurian uplift of the Cobequid Highlands. Following this regional Alleghenian event, there was no significant motion on the northern faults of the Cobequid shear zone and deformation moved southward to the Cobequid fault and its continuation in the Hollow and Chedabucto fault zones. Hydrothermal alteration, probably driven by a mid-crustal gabbro heat source, was widespread along the Cobequid and Rockland Brook faults in the early Carboniferous, resulting in albitization, potassic alteration, and iron mineralization.

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