the geologic history of Sedona rocks AZ, assignment help

Description

1 page summary of the geologic history of Sedona rocks AZ there is more details on the attachment picture

5 attachmentsSlide 1 of 5attachment_1attachment_1attachment_2attachment_2attachment_3attachment_3attachment_4attachment_4attachment_5attachment_5

Unformatted Attachment Preview

m
Pt
ar Anderson Canyon in
pre-volcanic erosion surface
the northeastern part of the quadrangle; truncated southwestward by
Kaibab Formation (Lower Permian)—Yellowish-gray to light-gray, silty
to sandy dolomite, limestone, commonly dolomitic and cherty, and
lenses of light-brown, fine-grained sandstone. In southern part of
quadrangle a conspicuous unit of brachiopodal limestone, about 7
(20 ft) thick, lies about 10 m (30 ft) above the base of the formation.
Uneven unconformity at base. Maximum thickness about 190 m (620
ft) near Blue Ridge Reservoir in southeastern part of quadrangle;
truncated irregularly southwestward by pre-volcanic erosion surface
Toroweap Formation (Lower Permian)-Light-gray to yellowish-gray,
very fine to fine-grained, quartzose sandstone in medium-scale sets of
crossbeds and rare horizontal beds. Base generally marked by
conspicuous horizontal recess in cliff formed by combination of
Toroweap with the Coconino Sandstone (Pc). Not recognized in
southern part of quadrangle near West and East Clear Creeks;
apparently merges with Coconino Sandstone. Commonly about 90 m
(300 ft) thick; attains maximum thickness of about 120 m (400 ft) in
Woods Canyon, east-southeast of Sedona in the northwestern part of
the quadrangle
Coconino Sandstone (Lower Permian)-Light-gray to yellowish-gray,
very fine to fine-grained quartzose sandstone, mostly in large-scale
sets of crossbeds; sparse lenses of horizontally bedded, reddish-gray,
fine-grained sandstone near base. Forms cliffs. Base of formation is
arbitrarily located in zone, 3-30 m (10-100 ft) thick, of transitional
lithology. Ranges in thickness from about 120-300 m (400-1,000 ft)
Toroweap Formation and Coconino Sandstone, undivided (Lower
Permian)
Pc
Ptc
Ptcs
Toroweap Formation, Coconino Sandstone, and upper part of the
Supai Formation, undivided (Lower Permian)
Supai Formation-On this map follows approximately the usage of Huddle
and Dobrovolny (1945) and of McKee (1945). Formations of the Supai
Group defined in the Grand Canyon by McKee (1975, 1982, p. 1-50)
have not been generally recognized in this quadrangle. Studies by
Blakey (1979a,b; 1980) and by Elston and DiPaolo (1979) have led to
different suggestions for major revisions in the formal nomenclature of
the strata here mapped as the Supai Formation
Upper part (Lower Permian)—Sandstone, siltstone, limestone, and
dolomitic limestone. Chiefly reddish-brown, very fine to fine-grained
sandstone and silty sandstone in medium to thick horizontal beds.
Limestone and dolomitic limestone, light gray to medium gray, fine
to four thin sets of thin to medium horizontal beds;
Psu
ka
Pt
ear Anderson Canyon in
the northeastern part of the quadrangle; truncated southwestward by
pre-volcanic erosion surface
Kaibab Formation (Lower Permian)—Yellowish-gray to light-gray, silty
to sandy dolomite, limestone, commonly dolomitic and cherty, and
lenses of light-brown, fine-grained sandstone. In southern part of
quadrangle a conspicuous unit of brachiopodal limestone, about 7 m
(20 ft) thick, lies about 10 m (30 ft) above the base of the formation.
Uneven unconformity at base. Maximum thickness about 190 m (620
ft) near Blue Ridge Reservoir in southeastern part of quadrangle;
truncated irregularly southwestward by pre-volcanic erosion surface
Toroweap Formation (Lower Permian)—Light-gray to yellowish-gray,
very fine to fine-grained, quartzose sandstone in medium-scale sets of
crossbeds and rare horizontal beds. Base generally marked by
conspicuous horizontal recess in cliff formed by combination of
Toroweap with the Coconino Sandstone (Pc). Not recognized in
southern part of quadrangle near West and East Clear Creeks;
apparently merges with Coconino Sandstone. Commonly about 90 m
(300 ft) thick; attains maximum thickness of about 120 m (400 ft) in
Woods Canyon, east-southeast of Sedona in the northwestern part of
the quadrangle
Coconino Sandstone (Lower Permian)—Light-gray to yellowish-gray,
very fine to fine-grained quartzose sandstone, mostly in large-scale
sets of crossbeds; sparse lenses of horizontally bedded, reddish-gray,
fine-grained sandstone near base. Forms cliffs. Base of formation is
arbitrarily located in zone, 3-30 m (10-100 ft) thick, of transitional
lithology. Ranges in thickness from about 120-300 m (400-1,000 ft)
Toroweap Formation and Coconino Sandstone, undivided (Lower
Permian)
Pc
Ptc
Ptcs
Toroweap Formation, Coconino Sandstone, and upper part of the
Supai Formation, undivided (Lower Permian)
Supai Formation-On this map follows approximately the usage of Huddle
and Dobrovolny (1945) and of McKee (1945). Formations of the Supai
Group defined in the Grand Canyon by McKee (1975, 1982, p. 1-50)
have not been generally recognized in this quadrangle. Studies by
Blakey (1979a,b; 1980) and by Elston and DiPaolo (1979) have led to
different suggestions for major revisions in the formal nomenclature of
the strata here mapped as the Supai Formation
Upper part (Lower Permian)-Sandstone, siltstone, limestone, and
dolomitic limestone. Chiefly reddish-brown, very fine to fine-grained
sandstone and silty sandstone in medium to thick horizontal beds.
Limestone and dolomitic limestone, light gray to medium gray, fine
to four thin sets of thin to medium horizontal beds;
1
Psu
ОГ
Groundniass is glassy.
15 pm
blende that average 2 mm in diameter and are as much as 6 mm and
phenocrysts of plagioclase that average 2 mm in diameter and are as
much as 4 mm. Forms prominent lava dome on south flank of
Mormon Mountain and small dome northeast of Coyote Basin, both
in north-central part of quadrangle
Sedimentary rocks (Miocene or older Tertiary)-Chiefly conglom-
erate, locally interbedded with sandstone, mudstone, and limestone;
light brown to light gray; semiconsolidated to well indurated; stream,
lake, and fan deposits of several generations and different source
areas (Peirce and others, 1979; Peirce and Nations, 1986; and Conway
and others, 1986). Mainly pre-volcanic but also rarely interbedded
with older basalt as in Rarick Canyon (G. H. Billingsley, oral
commun., 1985); in part assigned to Hickey Formation (Levings,
1980). Pebbles and cobbles are well rounded; composed of Precam-
brian igneous and metamorphic rocks derived primarily from southern
terranes, and (or) resistant Paleozoic rocks, chiefly the Kaibab
Formation and the Coconino Sandstone from the plateau on the
north. Distinctive clasts of black rhyolite and rhyodacite porphyry in
the deposits on Blue Ridge are identical to rocks exposed only in the
New River Mountains, about 80 km (50 mi) south-southwest of the
quadrangle (C. M. Conway, oral commun., 1985). Interbedded with
the conglomerate in a generally upward-fining sequence are fluvial and
lacustrine sandstone, mudstone, and limestone.
The sedimentary rocks rest unconformably on uneven, locally
markedly channeled, surfaces truncating Mesozoic and Paleozoic
rocks, commonly overlain unconformably by Tertiary volcanic rocks.
Discontinuous; thickness variable, generally less than 15 m (50 ft)
thick, but as much as 37 m (120 ft) thick on Blue Ridge in the
southeastern part of the quadrangle and in paleochannel exposed
along walls of canyon of Wet Beaver Creek in the southwestern part
of the quadrangle (Ulrich and others, 1983), and more than 110 m (360
ft) thick along West Clear Creek, (Ulrich and Bielski, 1983)
tul
ba
do on
Tb
PS
ilicic and mostly very fire gr
un lluvial deposits, composed mostly of granules to boulders of
ilesser dacite and minor admixtures of Paleozoic dolomite,
limestone, and sandstone; in part crossbedded and in cut-
an tructures. Along the margin of the basin the clastic facies
loc atertongues with volcanic rocks, chiefly basalt flows and
de
pyroclastic deposits. Maximum thickness of formation esti-
m by Nations and others (1981, p. 134) to be more than 945 m
(jft)
Volcac rocks (Pliocene? and Miocene)
Basaltic volcanic rocks, undifferentiated—Mainly medium gray to dark
gray, weathering dark grayish brown, aphanitic to coarse grained,
commonly porphyritic; locally vesicular; outcrop yields irregular
blocks. Groundmass is generally micrograined to very fine grained,
composed of acicular plagioclase, clinopyroxene, olivine, and opaque
oxides. Olivine phenocrysts average 1-2 mm in diameter in finer
grained rock and 3-4 mm in coarser grained rock and are as much as 4
cm across; clinopyroxene phenocrysts average 1-2 mm and are as
much as 1 cm across; plagioclase phenocrysts average 1-2 mm and
are as much as 1 cm across; less common quartz xenocrysts average
1-2 mm and are as much as 8 mm across. Mafic and ultramafic
xenoliths occur in several cinder cones and their associated lava
flows; mafic xenoliths are gabbroic and are as much as 5 cm in
diameter; ultramafic xenoliths are olivine pyroxenite and dunite and
are as much as 8 cm in diameter.
The basaltic rocks are commonly vesicular and in flow units 6-12 m
(20-40 ft) thick; also include basaltic tuffs, dikes, cinder cones, and
vent deposits too small to show separately. Map unit includes sparse
thin but conspicuous, light-colored silicic ash deposits (mainly dacite)
and some andesite in thin flows and small intrusions.
For the most part, the volcanic rocks unconformably overlie the
Permian Kaibab Formation (Pk); in the eastern part of the quadrangle
they overlie the truncated Triassic Moenkopi Formation (km); locally,
as on Blue Ridge in the southeastern part of the quadrangle, they
overlie Tertiary sedimentary rocks; a few flows are intercalated in the
Verde Formation (Tv).
Basaltic rocks on and near Casner Mountain in the northwestern part
of the quadrangle and in the Black Hills in the southwestern part of the
quadrangle have been assigned to the Hickey Formation of Miocene
age (Levings, 1980; Wolfe, 1983). Isotopically dated basalt flows in the
quadrangle range in age from 15.4 to 5.5 Ma (Peirce and others, 1979,
p. 7-9; McKee and Anderson, 1971, p. 2770).
Thickness of volcanic rocks differs markedly from place to place
because of original variations in deposition and subsequent erosion.
Aggregate flows commonly range from about 15 to 90 m (50-300 ft) in
thickness on uplands but generally thicken to more than 300 m (1,000
ft) along the margin of Verde Valley
Basaltic vent deposits-Complex deposits of basalt, commonly form
small shield volcanoes or eroded cones. Consist mainly of lavas,
agglomerate, spatter, and relatively small amounts of cinder. Com-
comnlexes. Vent deposits not mapped
Psum
PPs!
Tbv
ur
n
Tb
PS
tu
ilicic and mostly very
lluvial deposits, composed mostly of granules to boulders of
ba i lesser dacite and minor admixtures of Paleozoic dolomite,
do
limestone, and sandstone; in part crossbedded and in cut-
ar tructures. Along the margin of the basin the clastic facies
lo ntertongues with volcanic rocks, chiefly basalt flows and
d pyroclastic deposits. Maximum thickness of formation esti-
by Nations and others (1981, p. 134) to be more than 945 m
luft)
Volca c rocks (Pliocene? and Miocene)
Basaltic volcanic rocks, undifferentiated—Mainly medium gray to dark
gray, weathering dark grayish brown, aphanitic to coarse grained,
commonly porphyritic; locally vesicular; outcrop yields irregular
blocks. Groundmass is generally micrograined to very fine grained,
composed of acicular plagioclase, clinopyroxene, olivine, and opaque
oxides. Olivine phenocrysts average 1-2 mm in diameter in finer
grained rock and 3-4 mm in coarser grained rock and are as much as 4
cm across; clinopyroxene phenocrysts average 1-2 mm and are as
much as 1 cm across; plagioclase phenocrysts average 1-2 mm and
are as much as 1 cm across; less common quartz xenocrysts average
1-2 mm and are as much as 8 mm across. Mafic and ultramafic
xenoliths occur in several cinder cones and their associated lava
flows; mafic xenoliths are gabbroic and are as much as 5 cm in
diameter; ultramafic xenoliths are olivine pyroxenite and dunite and
are as much as 8 cm in diameter.
The basaltic rocks are commonly vesicular and in flow units 6-12 m
(20-40 ft) thick; also include basaltic tuffs, dikes, cinder cones, and
vent deposits too small to show separately. Map unit includes sparse
thin but conspicuous, light-colored silicic ash deposits (mainly dacite)
and some andesite in thin flows and small intrusions.
For the most part, the volcanic rocks unconformably overlie the
Permian Kaibab Formation (Pk); in the eastern part of the quadrangle
they overlie the truncated Triassic Moenkopi Formation (km); locally,
as on Blue Ridge in the southeastern part of the quadrangle, they
overlie Tertiary sedimentary rocks; a few flows are intercalated in the
Verde Formation (Tv).
Basaltic rocks on and near Casner Mountain in the northwestern part
of the quadrangle and in the Black Hills in the southwestern part of the
quadrangle have been assigned to the Hickey Formation of Miocene
age (Levings, 1980; Wolfe, 1983). Isotopically dated basalt flows in the
quadrangle range in age from 15.4 to 5.5 Ma (Peirce and others, 1979,
p. 7-9; McKee and Anderson, 1971, p. 2770).
Thickness of volcanic rocks differs markedly from place to place
because of original variations in deposition and subsequent erosion.
Aggregate flows commonly range from about 15 to 90 m (50-300 ft) in
thickness on uplands but generally thicken to more than 300 m (1,000
ft) along the margin of Verde Valley
Basaltic vent deposits-Complex deposits of basalt, commonly form
small shield volcanoes or eroded cones. Consist mainly of lavas,
agglomerate, spatter, and relatively small amounts of cinder. Com-
dile complexes. Vent deposits not mapped
Psum
PPs!
Tbv

Purchase answer to see full
attachment

User generated content is uploaded by users for the purposes of learning and should be used following Studypool’s honor code & terms of service.