scholarly journals Geology, igneous activity, and hydrothermal alteration in the Shimoda district, southern part of Izu Peninsula, central Japan

1985 ◽  
Vol 91 (1) ◽  
pp. 43-63_2 ◽  
Author(s):  
Ryo MATSUMOTO ◽  
Tetsuya KATAYAMA ◽  
Azuma IIJIMA
Keyword(s):  
Hydrothermal Alteration ◽  
Central Japan ◽  
Izu Peninsula ◽  
Igneous Activity

scholarly journals Opiliones of the Izu Peninsula, Central Japan

1972 ◽  
Vol 24 (2) ◽  
pp. 41-50 ◽  
Author(s):  
Seisho SUZUKI ◽  
Masahisa OHRUI
Keyword(s):  
Central Japan ◽  
Izu Peninsula

Coexistence of pyrophyllite, I-S, R1 and NH4+-rich illite in Silurian black shales (Sierra de Albarracín, NE Spain): metamorphic vs. hydrothermal origin

Clay Minerals ◽  
2010 ◽  
Vol 45 (3) ◽  
pp. 383-392 ◽  
Author(s):  
B. Bauluz ◽  
I. Subías
Keyword(s):  
Organic Matter ◽  
Clay Mineral ◽  
Hydrothermal Alteration ◽  
Black Shales ◽  
Low Grade ◽  
Lower Silurian ◽  
Igneous Activity ◽  
Upper Silurian ◽  
Ne Spain ◽  
Regional Tectonics

AbstractA set of Silurian black shales from Sierra de Albarracín (NE Spain) corresponding to two different sections was studied to determine the relative influence of diagenesis, igneous activity, and regional tectonics on the clay-mineral genesis. The coexistence of pyrophyllite, I-S interstratifications (R1), ammonium-rich illite, potassium illite, kaolin, and chlorite is not the result of prograde evolution during diagenesis – very low-grade metamorphism. Three different stages may be inferred: (1) sedimentation of black shales (Aeronian, Lower Silurian, to basal Ludfordian, Upper Silurian) and the subsequent diagenetic process producing the coexistence of quartz, illite, kaolinite, organic matter, etc.; (2) intrusion of andesitic sills producing hydrothermal alteration and crystallization of pyrophyllite, ammonium-rich illites, smectite, I-S R1 phases and jarosite; and (3) and folding of shales and sills and development of penetrative schistosity during the late Variscan leading to illite and paragonite recrystallization reaching the anchizone grade.

Carboniferous dikes of West Connacht, Ireland

1987 ◽  
Vol 78 (3) ◽  
pp. 133-151 ◽  
Author(s):  
J. G. Mitchell ◽  
P. Mohr
Keyword(s):  
Hydrothermal Alteration ◽  
North Atlantic ◽  
Late Carboniferous ◽  
Alkaline Basalt ◽  
Mid Ocean Ridge ◽  
Igneous Activity ◽  
Basalt Geochemistry ◽  
Granite Batholith ◽  
Ocean Ridge

ABSTRACTVigorous Carboniferous extensional tectonism and associated igneous activity is a feature of Ireland and the neighbouring areas of Newfoundland and Britain. In West Connacht, Ireland, dolerite dikes of late Carboniferous age are newly recognised and distinguished from Tertiary dolerites. In the N, the 320 Ma-old Logmor dike trends N–S across the Ordovician South Mayo Trough, and has an evolved, mildly alkaline basalt geochemistry. In the S, in Connemara, a diffuse and arcuate swarm of ENE–NE trending, 305 Ma-old dolerite dikes, the Teach Doite swarm, cuts the Galway Granite batholith and its envelope of Dalradian gneisses. These more tholeiitic dolerites reveal the mineralogical and geochemical effects of varying degrees of pervasive hydrothermal alteration, imposed on an original magmatic composition similar to that of mid-ocean ridge basalts. Variscan overprinting on k–Ar ages from West Connacht dolerites clusters at 300, 245 and 205 Ma. Overprinting is also a feature of much of the Galway Granite. Carboniferous diking in West Connacht may have responded to nascent opening of the proximate North Atlantic, its pattern related to domal uplift adjacent to the rifted zone.

Paleomagnetic Evidence of the Northward Drift of the Izu Peninsula, Central Japan

1985 ◽  
pp. 775-787 ◽  
Author(s):  
Kimio Hirooka ◽  
Toru Takahashi ◽  
Hideo Sakai ◽  
Tadashi Nakajima
Keyword(s):  
Central Japan ◽  
Izu Peninsula
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