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NARROW
GeoRef Subject
-
all geography including DSDP/ODP Sites and Legs
-
Africa
-
Central Africa (1)
-
East Africa
-
Kenya
-
Kenya Rift valley (1)
-
-
-
East African Rift (1)
-
North Africa
-
Egypt
-
Eastern Desert (1)
-
-
-
West Africa
-
Benue Valley (1)
-
Niger (1)
-
Nigeria
-
Jos Plateau (1)
-
-
-
-
Antarctica
-
Transantarctic Mountains
-
Queen Maud Range (1)
-
-
-
Asia
-
Arabian Peninsula
-
Saudi Arabia (5)
-
-
Buryat Russian Federation (1)
-
Far East
-
Japan
-
Honshu
-
Mino Belt (1)
-
-
-
-
Khakasiya Russian Federation (1)
-
Middle East
-
Israel
-
Makhtesh Ramon (1)
-
-
-
Sayan
-
Eastern Sayan (1)
-
-
Transbaikalia (1)
-
Tuva Russian Federation (1)
-
-
Atlantic Ocean
-
North Atlantic
-
North Sea (1)
-
-
-
Atlantic Ocean Islands
-
Azores
-
Sao Miguel Island (1)
-
-
-
Australasia
-
New Zealand (1)
-
Papua New Guinea (2)
-
-
Caledonides (1)
-
Cameroon Line (1)
-
Canada
-
Western Canada
-
British Columbia (6)
-
Canadian Cordillera (1)
-
-
-
Commonwealth of Independent States
-
Russian Federation
-
Buryat Russian Federation (1)
-
Khakasiya Russian Federation (1)
-
Transbaikalia (1)
-
Tuva Russian Federation (1)
-
-
-
Craters of the Moon (1)
-
East Pacific Ocean Islands
-
Hawaii
-
Hawaii County Hawaii
-
Hawaii Island
-
Kohala (1)
-
-
-
-
-
Espanola Basin (1)
-
Europe
-
Central Europe
-
Hungary (1)
-
Slovakia (1)
-
-
Southern Europe
-
Italy
-
Calabria Italy (1)
-
Sardinia Italy (1)
-
Sicily Italy
-
Lipari Islands
-
Lipari Island (1)
-
-
Mount Etna (1)
-
-
-
-
Western Europe
-
United Kingdom
-
Great Britain
-
England
-
East Midlands (1)
-
West Midlands (1)
-
-
Wales
-
South Wales (1)
-
Welsh Basin (1)
-
-
-
-
-
-
Grand Canyon (2)
-
Indian Ocean
-
Red Sea (1)
-
-
Indian Ocean Islands
-
Mauritius (1)
-
-
Mediterranean region (1)
-
Mediterranean Sea
-
Strait of Sicily (1)
-
-
Mexico
-
Colima Mexico (1)
-
Guanajuato Mexico (1)
-
Jalisco Block (1)
-
Jalisco Mexico
-
Guadalajara Mexico (1)
-
-
Michoacan-Guanajuato volcanic field (2)
-
Nayarit Mexico
-
Sanganguey (2)
-
-
Sierra Madre Occidental (1)
-
Sonora Mexico (2)
-
Trans-Mexican volcanic belt (4)
-
-
Midlands (1)
-
North America
-
Basin and Range Province (2)
-
North American Cordillera
-
Canadian Cordillera (1)
-
-
Rio Grande Rift (1)
-
-
North Island (1)
-
Oceania
-
Polynesia
-
French Polynesia
-
Marquesas Islands (1)
-
Tuamotu Islands
-
Mururoa Atoll (2)
-
-
-
Hawaii
-
Hawaii County Hawaii
-
Hawaii Island
-
Kohala (1)
-
-
-
-
-
-
Pacific Ocean
-
East Pacific
-
Northeast Pacific
-
Bowie Seamount (1)
-
Clarion fracture zone (1)
-
Hawaiian Ridge (2)
-
-
-
North Pacific
-
Northeast Pacific
-
Bowie Seamount (1)
-
Clarion fracture zone (1)
-
Hawaiian Ridge (2)
-
-
Northwest Pacific
-
Emperor Seamounts (2)
-
-
-
West Pacific
-
Northwest Pacific
-
Emperor Seamounts (2)
-
-
-
-
Red Sea region (3)
-
San Pedro (1)
-
Southern Ocean
-
Ross Sea
-
McMurdo Sound (1)
-
-
-
United States
-
Arizona
-
Graham County Arizona
-
Geronimo volcanic field (1)
-
-
Mohave County Arizona (2)
-
-
California
-
Mono County California
-
Mono Craters (1)
-
-
San Bernardino County California
-
Cima volcanic field (1)
-
-
-
Colorado Plateau (1)
-
Hawaii
-
Hawaii County Hawaii
-
Hawaii Island
-
Kohala (1)
-
-
-
-
Idaho (1)
-
Nevada
-
Nevada Test Site (1)
-
Nye County Nevada
-
Yucca Mountain (1)
-
-
-
New Mexico (2)
-
Texas
-
West Texas (1)
-
-
Trans-Pecos (2)
-
Utah
-
Washington County Utah (2)
-
-
-
-
commodities
-
glass materials (1)
-
metal ores
-
base metals (1)
-
gold ores (2)
-
silver ores (1)
-
-
-
elements, isotopes
-
carbon
-
C-13/C-12 (1)
-
C-14 (1)
-
-
chemical ratios (2)
-
halogens
-
chlorine
-
Cl-36 (1)
-
-
-
hydrogen
-
D/H (1)
-
-
isotope ratios (7)
-
isotopes
-
radioactive isotopes
-
C-14 (1)
-
Cl-36 (1)
-
Pb-206/Pb-204 (4)
-
Pb-207/Pb-204 (1)
-
Pb-208/Pb-204 (1)
-
-
stable isotopes
-
C-13/C-12 (1)
-
D/H (1)
-
Nd-144/Nd-143 (8)
-
O-18/O-16 (2)
-
Pb-206/Pb-204 (4)
-
Pb-207/Pb-204 (1)
-
Pb-208/Pb-204 (1)
-
S-34/S-32 (1)
-
Sr-87/Sr-86 (10)
-
-
-
metals
-
alkaline earth metals
-
magnesium (1)
-
strontium
-
Sr-87/Sr-86 (10)
-
-
-
iron (2)
-
lead
-
Pb-206/Pb-204 (4)
-
Pb-207/Pb-204 (1)
-
Pb-208/Pb-204 (1)
-
-
precious metals (1)
-
rare earths
-
neodymium
-
Nd-144/Nd-143 (8)
-
-
-
titanium (1)
-
-
oxygen
-
O-18/O-16 (2)
-
-
sulfur
-
S-34/S-32 (1)
-
-
-
geochronology methods
-
Ar/Ar (3)
-
exposure age (1)
-
K/Ar (7)
-
Pb/Pb (1)
-
Sm/Nd (1)
-
U/Pb (1)
-
-
geologic age
-
Cenozoic
-
Quaternary
-
Holocene
-
upper Holocene
-
Roman period (1)
-
-
-
Pleistocene
-
middle Pleistocene (1)
-
upper Pleistocene (2)
-
-
-
Tertiary
-
Neogene
-
Miocene
-
Crater Flat Tuff (1)
-
upper Miocene (2)
-
-
Pliocene
-
lower Pliocene (1)
-
upper Pliocene (1)
-
-
-
Paleogene
-
Eocene (1)
-
-
upper Tertiary (2)
-
-
upper Cenozoic (3)
-
-
Mesozoic
-
Cretaceous
-
Upper Cretaceous (3)
-
-
Jurassic (1)
-
-
Paleozoic
-
Carboniferous
-
Upper Carboniferous
-
Westphalian (1)
-
-
-
Silurian (1)
-
-
Precambrian (1)
-
-
igneous rocks
-
igneous rocks
-
picrite (1)
-
plutonic rocks
-
diorites (1)
-
gabbros (3)
-
granites
-
charnockite (1)
-
-
monzonites (1)
-
syenites (2)
-
ultramafics
-
peridotites
-
spinel lherzolite (1)
-
-
pyroxenite (1)
-
-
-
volcanic rocks
-
andesites (8)
-
basalts
-
alkali basalts
-
alkali olivine basalt (6)
-
hawaiite (55)
-
mugearite (27)
-
trachybasalts (1)
-
-
mid-ocean ridge basalts (2)
-
olivine basalt (1)
-
tholeiite (4)
-
tholeiitic basalt (3)
-
-
basanite
-
ankaramite (1)
-
-
benmoreite (6)
-
glasses
-
volcanic glass (1)
-
-
latite (1)
-
nephelinite
-
olivine nephelinite (1)
-
-
phonolites (3)
-
pyroclastics
-
ignimbrite (1)
-
pumice (1)
-
scoria (1)
-
tuff (2)
-
-
rhyolites (6)
-
trachytes (6)
-
-
-
volcanic ash (1)
-
-
metamorphic rocks
-
metamorphic rocks
-
granulites (1)
-
schists
-
greenstone (1)
-
-
-
-
minerals
-
carbonates
-
calcite (1)
-
-
minerals (1)
-
oxides
-
chromite (2)
-
ilmenite (1)
-
iron oxides (1)
-
spinel (1)
-
spinel group (1)
-
titanomagnetite (1)
-
ulvospinel (1)
-
-
phosphates
-
apatite (2)
-
-
silicates
-
chain silicates
-
aenigmatite group
-
rhonite (1)
-
-
amphibole group
-
clinoamphibole
-
hornblende (1)
-
-
-
pyroxene group
-
clinopyroxene
-
augite (1)
-
diopside (1)
-
-
orthopyroxene
-
hypersthene (1)
-
-
-
-
framework silicates
-
feldspar group
-
plagioclase (3)
-
-
silica minerals
-
quartz (1)
-
-
-
orthosilicates
-
nesosilicates
-
garnet group (1)
-
olivine group
-
olivine (6)
-
-
zircon group
-
zircon (1)
-
-
-
-
sheet silicates
-
clay minerals
-
nontronite (1)
-
saponite (1)
-
smectite (2)
-
-
corrensite (1)
-
mica group
-
biotite (1)
-
celadonite (1)
-
-
-
-
sulfides
-
pyrrhotite (1)
-
sphalerite (1)
-
-
-
Primary terms
-
absolute age (13)
-
Africa
-
Central Africa (1)
-
East Africa
-
Kenya
-
Kenya Rift valley (1)
-
-
-
East African Rift (1)
-
North Africa
-
Egypt
-
Eastern Desert (1)
-
-
-
West Africa
-
Benue Valley (1)
-
Niger (1)
-
Nigeria
-
Jos Plateau (1)
-
-
-
-
Antarctica
-
Transantarctic Mountains
-
Queen Maud Range (1)
-
-
-
Asia
-
Arabian Peninsula
-
Saudi Arabia (5)
-
-
Buryat Russian Federation (1)
-
Far East
-
Japan
-
Honshu
-
Mino Belt (1)
-
-
-
-
Khakasiya Russian Federation (1)
-
Middle East
-
Israel
-
Makhtesh Ramon (1)
-
-
-
Sayan
-
Eastern Sayan (1)
-
-
Transbaikalia (1)
-
Tuva Russian Federation (1)
-
-
Atlantic Ocean
-
North Atlantic
-
North Sea (1)
-
-
-
Atlantic Ocean Islands
-
Azores
-
Sao Miguel Island (1)
-
-
-
Australasia
-
New Zealand (1)
-
Papua New Guinea (2)
-
-
Canada
-
Western Canada
-
British Columbia (6)
-
Canadian Cordillera (1)
-
-
-
carbon
-
C-13/C-12 (1)
-
C-14 (1)
-
-
Cenozoic
-
Quaternary
-
Holocene
-
upper Holocene
-
Roman period (1)
-
-
-
Pleistocene
-
middle Pleistocene (1)
-
upper Pleistocene (2)
-
-
-
Tertiary
-
Neogene
-
Miocene
-
Crater Flat Tuff (1)
-
upper Miocene (2)
-
-
Pliocene
-
lower Pliocene (1)
-
upper Pliocene (1)
-
-
-
Paleogene
-
Eocene (1)
-
-
upper Tertiary (2)
-
-
upper Cenozoic (3)
-
-
chemical analysis (2)
-
clay mineralogy (2)
-
crust (6)
-
crystal growth (1)
-
crystal structure (1)
-
East Pacific Ocean Islands
-
Hawaii
-
Hawaii County Hawaii
-
Hawaii Island
-
Kohala (1)
-
-
-
-
-
Europe
-
Central Europe
-
Hungary (1)
-
Slovakia (1)
-
-
Southern Europe
-
Italy
-
Calabria Italy (1)
-
Sardinia Italy (1)
-
Sicily Italy
-
Lipari Islands
-
Lipari Island (1)
-
-
Mount Etna (1)
-
-
-
-
Western Europe
-
United Kingdom
-
Great Britain
-
England
-
East Midlands (1)
-
West Midlands (1)
-
-
Wales
-
South Wales (1)
-
Welsh Basin (1)
-
-
-
-
-
-
faults (3)
-
fractures (2)
-
geochemistry (25)
-
geochronology (3)
-
geomorphology (3)
-
hydrogen
-
D/H (1)
-
-
igneous rocks
-
picrite (1)
-
plutonic rocks
-
diorites (1)
-
gabbros (3)
-
granites
-
charnockite (1)
-
-
monzonites (1)
-
syenites (2)
-
ultramafics
-
peridotites
-
spinel lherzolite (1)
-
-
pyroxenite (1)
-
-
-
volcanic rocks
-
andesites (8)
-
basalts
-
alkali basalts
-
alkali olivine basalt (6)
-
hawaiite (55)
-
mugearite (27)
-
trachybasalts (1)
-
-
mid-ocean ridge basalts (2)
-
olivine basalt (1)
-
tholeiite (4)
-
tholeiitic basalt (3)
-
-
basanite
-
ankaramite (1)
-
-
benmoreite (6)
-
glasses
-
volcanic glass (1)
-
-
latite (1)
-
nephelinite
-
olivine nephelinite (1)
-
-
phonolites (3)
-
pyroclastics
-
ignimbrite (1)
-
pumice (1)
-
scoria (1)
-
tuff (2)
-
-
rhyolites (6)
-
trachytes (6)
-
-
-
inclusions
-
fluid inclusions (3)
-
-
Indian Ocean
-
Red Sea (1)
-
-
Indian Ocean Islands
-
Mauritius (1)
-
-
intrusions (5)
-
isotopes
-
radioactive isotopes
-
C-14 (1)
-
Cl-36 (1)
-
Pb-206/Pb-204 (4)
-
Pb-207/Pb-204 (1)
-
Pb-208/Pb-204 (1)
-
-
stable isotopes
-
C-13/C-12 (1)
-
D/H (1)
-
Nd-144/Nd-143 (8)
-
O-18/O-16 (2)
-
Pb-206/Pb-204 (4)
-
Pb-207/Pb-204 (1)
-
Pb-208/Pb-204 (1)
-
S-34/S-32 (1)
-
Sr-87/Sr-86 (10)
-
-
-
lava (25)
-
magmas (34)
-
mantle (11)
-
Mediterranean region (1)
-
Mediterranean Sea
-
Strait of Sicily (1)
-
-
Mesozoic
-
Cretaceous
-
Upper Cretaceous (3)
-
-
Jurassic (1)
-
-
metal ores
-
base metals (1)
-
gold ores (2)
-
silver ores (1)
-
-
metals
-
alkaline earth metals
-
magnesium (1)
-
strontium
-
Sr-87/Sr-86 (10)
-
-
-
iron (2)
-
lead
-
Pb-206/Pb-204 (4)
-
Pb-207/Pb-204 (1)
-
Pb-208/Pb-204 (1)
-
-
precious metals (1)
-
rare earths
-
neodymium
-
Nd-144/Nd-143 (8)
-
-
-
titanium (1)
-
-
metamorphic rocks
-
granulites (1)
-
schists
-
greenstone (1)
-
-
-
metamorphism (2)
-
metasomatism (4)
-
Mexico
-
Colima Mexico (1)
-
Guanajuato Mexico (1)
-
Jalisco Block (1)
-
Jalisco Mexico
-
Guadalajara Mexico (1)
-
-
Michoacan-Guanajuato volcanic field (2)
-
Nayarit Mexico
-
Sanganguey (2)
-
-
Sierra Madre Occidental (1)
-
Sonora Mexico (2)
-
Trans-Mexican volcanic belt (4)
-
-
mineralogy (1)
-
minerals (1)
-
North America
-
Basin and Range Province (2)
-
North American Cordillera
-
Canadian Cordillera (1)
-
-
Rio Grande Rift (1)
-
-
ocean floors (2)
-
Oceania
-
Polynesia
-
French Polynesia
-
Marquesas Islands (1)
-
Tuamotu Islands
-
Mururoa Atoll (2)
-
-
-
Hawaii
-
Hawaii County Hawaii
-
Hawaii Island
-
Kohala (1)
-
-
-
-
-
-
orogeny (1)
-
oxygen
-
O-18/O-16 (2)
-
-
Pacific Ocean
-
East Pacific
-
Northeast Pacific
-
Bowie Seamount (1)
-
Clarion fracture zone (1)
-
Hawaiian Ridge (2)
-
-
-
North Pacific
-
Northeast Pacific
-
Bowie Seamount (1)
-
Clarion fracture zone (1)
-
Hawaiian Ridge (2)
-
-
Northwest Pacific
-
Emperor Seamounts (2)
-
-
-
West Pacific
-
Northwest Pacific
-
Emperor Seamounts (2)
-
-
-
-
paleogeography (1)
-
Paleozoic
-
Carboniferous
-
Upper Carboniferous
-
Westphalian (1)
-
-
-
Silurian (1)
-
-
paragenesis (2)
-
petrology (19)
-
phase equilibria (4)
-
plate tectonics (9)
-
pollution (2)
-
Precambrian (1)
-
Red Sea region (3)
-
sedimentary rocks
-
clastic rocks (2)
-
-
Southern Ocean
-
Ross Sea
-
McMurdo Sound (1)
-
-
-
spectroscopy (1)
-
stratigraphy (3)
-
sulfur
-
S-34/S-32 (1)
-
-
tectonics (2)
-
tectonophysics (5)
-
United States
-
Arizona
-
Graham County Arizona
-
Geronimo volcanic field (1)
-
-
Mohave County Arizona (2)
-
-
California
-
Mono County California
-
Mono Craters (1)
-
-
San Bernardino County California
-
Cima volcanic field (1)
-
-
-
Colorado Plateau (1)
-
Hawaii
-
Hawaii County Hawaii
-
Hawaii Island
-
Kohala (1)
-
-
-
-
Idaho (1)
-
Nevada
-
Nevada Test Site (1)
-
Nye County Nevada
-
Yucca Mountain (1)
-
-
-
New Mexico (2)
-
Texas
-
West Texas (1)
-
-
Trans-Pecos (2)
-
Utah
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Washington County Utah (2)
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volcanology (12)
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waste disposal (1)
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X-ray analysis (1)
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sedimentary rocks
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sedimentary rocks
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clastic rocks (2)
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hawaiite
Origin of low Mg# hawaiites carrying peridotite xenoliths from the Cima volcanic field, California, USA: Evidence of rapid magma mixing during ascent along intersecting fractures
Origin of alkali olivine basalts and hawaiites in the western Mexican arc: Evidence of rapid phenocryst growth and magma mixing during ascent along fractures
Abstract This study discusses the petrological and geochemical features of two monogenetic Miocene volcanoes, Mount Early and Sheridan Bluff, which are the above-ice expressions of Earth's southernmost volcanic field located at c. 87° S on the East Antarctic Craton. Their geochemistry is compared to basalts from the West Antarctic Rift System to test affiliation and resolve mantle sources and cause of melting beneath East Antarctica. Basaltic lavas and dykes are olivine-phyric and comprise alkaline (hawaiite and mugearite) and subalkaline (tholeiite) types. Trace element abundances and ratios (e.g. La/Yb, Nb/Y, Zr/Y) of alkaline compositions resemble basalts from the West Antarctic rift and ocean islands (OIB), while tholeiites are relatively depleted and approach the concentrations levels of enriched mid-ocean ridge basalt (E-MORB). The magmas evolved by fractional crystallization with contamination by crust; however, neither process can adequately explain the contemporaneous eruption of hawaiite and tholeiite at Sheridan Bluff. Our preferred scenario is that primary magmas of each type were produced by different degrees of partial melting from a compositionally similar mantle source. The nearly simultaneous generation of lower degrees of melting to produce alkaline types and higher degrees of melting forming tholeiite was most likely to have been facilitated by the detachment and dehydration of metasomatized mantle lithosphere.
The timing and compositional evolution of volcanism within northern Harrat Rahat, Kingdom of Saudi Arabia
Petrology and geochemistry of the Valle de Santiago lower-crust xenoliths: Young tectonothermal processes beneath the central Trans-Mexican volcanic belt
Micro-FTIR imaging: an advanced method for the determination of CO 2 and H 2 O concentration gradients in silicate glasses
Archaeometric study of the hopper-rubber and rotary Morgantina-type volcanic millstones of the Greek and Roman periods found in the Aeolian archipelago (southern Italy)
Rhönite in alkali basalts: silicate melt inclusions in olivine phenocrysts
Alkaline magmatism along the Cameroon Line has been active for at least 67 m.y. and is currently defined by an almost SW-NE geological lineament (mean value: N30°E). Available petrological, geochemical, and structural data obtained over the last 20 yr lead us to reappraise its mechanism of emplacement. Known as the second most important geological curiosity in Africa, after the East African Rift system, it displays a continental part and an oceanic part, a unique feature in Africa and even in the world. The continental part contains both plutonic and volcanic massifs, and the oceanic part consists only of volcanic massifs. Plutonic rocks as a whole define a complete series of gabbro-diorite-monzonite-syenite-granite type, whereas volcanic rocks display abundant basic (basalt-hawaiite) and felsic (trachyte-phonolite-rhyolite) lavas with very few intermediate ones (mugearite-benmoreite). The formerly entire alkaline nature of these rocks is here ruled out by the discovery of volcanoes with geochemically transitional affinities in some areas of the continental sector. On the other hand, new K-Ar and 40 Ar/ 39 Ar dates confirm the absence of any age migration associated with the SW-NE linear trend. This lack of steady time-space migration and the SW-NE trend have also been observed in the magmatic provinces of Nigeria and Benue Trough, which share similar geochemical features with the Cameroon Line, and along the NE-SW major igneous lineaments in South Africa. The mechanism of such episodic emplacement of alkaline magmatism can be better explained in terms of complex interactions between hotspots and lithospheric fractures during African plate motion.
CLAY MINERALS IN BASALT-HAWAIITE ROCKS FROM MURUROA ATOLL (FRENCH POLYNESIA). I. MINERALOGY
CLAY MINERALS IN BASALT-HAWAIITE ROCKS FROM MURUROA ATOLL (FRENCH POLYNESIA). II. PETROGRAPHY AND GEOCHEMISTRY
Origin and evolution of the Pleistocene magmatism of Linosa Island (Sicily Channel, Italy)
The geochemical peculiarity of “Plio-Quaternary” volcanic rocks of Sardinia in the circum-Mediterranean area
Late Cenozoic volcanic rocks on the island of Sardinia are mildly alkaline-transitional lavas, dominantly hawaiites, mugearites, and transitional basalts with minor phonolites and trachytes, which form ∼80% of the entire sample population. Tholeiitic basaltic andesites form the remaining 20% of the analyzed rocks. The oldest lavas, the ca. 6.6–4.4 Ma radiogenic Pb volcanic group, are in southern Sardinia; they have geochemical characteristics very similar to most Circum-Mediterranean Anorogenic Cenozoic Igneous Province rocks. After a gap of ∼0.5 m.y., volcanism occurred in central and northern Sardinia, from ca. 3.9 to ca. 0.1 Ma. These products, the unradiogenic Pb volcanic group, are geochemically very different. Their geochemical characteristics (relatively high SiO 2 , low CaO, and CaO/Al 2 O 3 , relatively high Ni, relatively low high field strength elements, low heavy rare earth elements, high Ba/Nb and La/Nb, slightly high 87 Sr/ 86 Sr, and unradiogenic 143 Nd/ 144 Nd and 206 Pb/ 204 Pb ratios) are considered to be derived from an orthopyroxene-rich lithospheric mantle source. The origin of this enrichment in orthopyroxene is a consequence of SiO 2 -rich melt derived from delaminated and detached ancient lower continental crust reacting with mantle peridotite. The presence of two distinct groups of rocks (unradiogenic Pb volcanics and radiogenic Pb volcanics) in a very close geographic position is related to the existence of a lithospheric discontinuity running roughly E-W in southern Sardinia.
The San Pedro–Cerro Grande volcanic complex (Nayarit, México): Inferences on volcanology and magma evolution
This study focuses on two issues that are still a matter of debate in subduction zones, particularly in western México: (1) the close association within the same volcanic complex of typical amphibole-free andesites to rhyolites and amphibole-bearing andesites to rhyolites, characteristic of the hydrated front of the Mexican arc; and (2) the occurrence of bimodal magmatism without evidence for interaction between mafic and intermediate to silicic magmas, which are in addition characterized by different petrogenetic affinities. Our case study is the San Pedro–Cerro Grande volcanic complex, a Quaternary silicic to intermediate dome complex located in western Mexico. Volcanic activity has been divided into two periods. In the middle Pleistocene, andesitic to dacitic magmas were emplaced along WNW-trending faults in the southern portion of the complex. The Las Cuevas pyroclastic sequence (older than ca. 500 ka) was emplaced during this episode, most likely from a local source. This first period of activity ended before ca. 280 ka with the emplacement of the Cuastecomate Plinian deposit, which is related to the formation of the San Pedro caldera, an ∼4-km-wide subcircular depression that is today partially buried by younger volcanic products. During the second period of activity (ca. 280–30 ka), rhyolitic and dacitic domes were mostly emplaced along the caldera rim and inside the caldera. In addition, hawaiites and mugearites built the Amado Nervo shield volcano on the caldera rim. Intermediate- to high-silica lava and pyroclastic rocks are subalkaline, whereas the Amado Nervo mafic lavas are transitional toward the alkaline series (Na-alkaline). No genetic relationships have been found between subalkaline and transitional Na-alkaline rocks, which are thought to represent different batches of magma from different mantle sources. Petrographic, geochemical, and isotopic variations observed in the transitional Na-alkaline Amado Nervo lavas point to a parental magma from a mantle melt that underwent limited olivine separation during its ascent to the surface. Among subalkaline rocks, two groups showing contrasting petrographical and geochemical features are recognized based on the presence of amphibole. Amphibole-bearing intermediate to silicic rocks are characterized by lower Ce and other incompatible trace element contents and lower 87 Sr/ 86 Sr (0.70382–0.70401) compared to amphibole-free rocks (0.70411–0.70424). On the basis of petrological characteristics, the two groups of magmas are interpreted to have evolved in two different magmatic reservoirs under different pressures and water contents in the mid-upper crust. Both groups of magmas were differentiated by open-system processes. We propose that assimilation and equilibrium crystallization (AEC) processes account for the amphibole-bearing rocks. Hotter and less evolved magmas interacted to a higher degree with the crust than the more evolved and colder magmas. This produced the observed higher 87 Sr/ 86 Sr in the less differentiated rocks of the amphibole-bearing group. On the other hand, amphibole-free rocks have chemical and isotopic characteristics that can be modeled by assimilation and fractional crystallization (AFC) processes. All data suggest that the two groups of subalkaline rocks have been generated by a common parental hydrous magma, but evolved in two different reservoirs. Amphibole-bearing magmas underwent amphibole fractionation in a mid-upper crustal reservoir and show assimilation of two types of basement: one akin to Oaxaquia and another akin to the Guerrero terrane. Amphibole-free magma only shows assimilation of an Oaxaquia-type basement.