Rock Canyon near Provo, Utah is an ideal outdoor laboratory. Th e
canyon has been known and explo... more Rock Canyon near Provo, Utah is an ideal outdoor laboratory. Th e canyon has been known and explored for many years by scientists and students for its fascinating geology, biology, and botany. It is also a favorite location for rock climbers, hikers, and other outdoor enthusiasts. Geology is the focal point of this beautiful canyon with a history that stretches from the Precambrian (about 700 million years ago) to the Wasatch fault and Lake Bonneville, which covered much of western Utah at its peak roughly 18,000 years ago. Excellent exposures of the rocks allow visitors to see features clearly and piece together the history of the canyon.
A history and genealogy of the descendants of David Duers (or Dewers) and Deborah Sherman includi... more A history and genealogy of the descendants of David Duers (or Dewers) and Deborah Sherman including the first 6 generations. The book includes many photos and stories.
Photos and letters written by Lieutenant R. T. Kowallis and his wife Norma Jensen Kowallis while ... more Photos and letters written by Lieutenant R. T. Kowallis and his wife Norma Jensen Kowallis while he was stationed in the Pacific during World War II in 1945. A higher resolution version of this book is available from the author upon request.
Copies of this book may be obtained from the Department of Geological Sciences, Brigham Young Uni... more Copies of this book may be obtained from the Department of Geological Sciences, Brigham Young University (contact: [email protected]).
This is a completely revised and updated version of the most widely used book on the geology of Utah in print. This book supplements the published geologic maps of Utah (Hintze, 1980, 1997, 2000f) by providing a third dimension, thickness, to the many map units whose areal extent is shown on the maps. The book also summarizes how these map units relate to Earth’s plate tectonic system. Much new information regarding Utah’s geologic past has been discovered in the the twenty-two years since the last edition of this book was published. Updates have been particularly striking in our understanding of plate tectonics, knowledge of Precambrian rocks, concepts and ages of volcanic events in the last 30 million years, documenting the history of Lake Bonneville within the last 30,000 years, and characterizing the activity of the Wasatch Fault within the last 5000 years. Fourteen new stratigraphic charts have been added and all of the text and figures, including the stratigraphic and correlation charts, have been completely revised. The book is directed primarily toward students in geology, but professional geologists working in Utah will find the stratigraphic and correlation charts useful, as well as the source literature citation list. Other interested persons will find the broad sweep of Utah’s geologic history fascinating.
The Uinta Mountains are an east-west-trending, reverse fault-bounded, basement-cored Laramide upl... more The Uinta Mountains are an east-west-trending, reverse fault-bounded, basement-cored Laramide uplift. The Eocene Duchesne River Formation and Oligocene Bishop Conglomerate represent late stage, intermontane basin fill of the Uinta Basin in northeastern Utah. Detailed mapping (1:24,000 scale), clast counts in conglomerate beds, description of lithology and stratigraphic contacts, and radiometric dating of pyroclastic fall beds of the Duchesne River Formation and Bishop Conglomerate in the Vernal NW quadrangle in northeastern Utah reveal stratal geometries of middle Cenozoic depositional units, the uplift and unroofing history of the eastern Uinta Mountains, and give evidence for the pulsed termination of Laramide uplift related to rollback of the Farallon slab and lithospheric delamination. These relationships show the continuation of Laramide uplift in this region until after 37.9 Ma and before 34 Ma, an age younger than the previously reported 45 to 40 Ma. The Duchesne River Format...
Textural and compositional variations in titanite constrain the roles of magma mixing and hydroth... more Textural and compositional variations in titanite constrain the roles of magma mixing and hydrothermal alteration in two plutons in central Utah: the Jurassic Notch Peak and the Oligocene Little Cottonwood stocks. In the Notch Peak intrusion, magmatic titanite grains usually have oscillatory zones combined with BSE-bright sector zones, in some cases surrounding simple unzoned cores. These grains are frequently overprinted by hydrothermal titanite with low concentrations of high field strength elements (HFSE). Magmatic titanite has an average δ18O of 6.0‰ and post-magmatic titanite is 6.2‰, as analyzed by SIMS. Average Zr-in-titanite temperatures are also similar, with 718 °C for magmatic and 711 °C for hydrothermal titanite. These observations indicate simple magmatic growth, followed by hydrothermal alteration by magmatic fluids. Titanite in aplite dikes and sills has lower concentrations of all trace elements except F. Many titanite grains in the aplites have late overgrowths of h...
Titanite is an accessory mineral in many granites. Due to its incorporation of a wide variety of ... more Titanite is an accessory mineral in many granites. Due to its incorporation of a wide variety of trace elements, low elemental diffusion rates, and relative abundance, titanite is useful in the study of petrogenetic processes. In addition, titanite also retains clear growth zoning from past events. We sampled titanite from two localities, the Notch Peak Granite located in Western Utah, and the Little Cottonwood stock located near Salt Lake City, Utah in order to evaluate Titanite textures in interpreting magmatic and hydrothermal histories.
The Miocene rhyolites of the Spor Mountain Formation host Earth's largest beryllium deposit, whic... more The Miocene rhyolites of the Spor Mountain Formation host Earth's largest beryllium deposit, which produced 85% of the world's beryllium in 2010. The fresh lava is extremely enriched in Be (up to 75 ppm in matrix glass). We have examined the rhyolite to better understand the Be enrichment. The Spor Mountain rhyolite contains ~40% quartz, ~40% sanidine, ~10% biotite, and ~10% plagioclase, along with accessory fluorite, columbite, euxenite, fergusonite, monazite, thorite, and zircon. Two types of rhyolite are present within the Spor Mountain Formation, a less-evolved magma (1150 ppm Rb, 42 ppm Be, 0.7 wt% F in glass) and a more-evolved magma (1710 ppm Rb, 75 ppm Be, 1.6 wt% F in glass). Eruption temperatures estimated using two-feldspar (
Geological Society of America Abstracts with Programs, 2018
Conclusions-Fe/Al ratios u The atomic ratio of Fe/Al in titanite from both volcanic and plutonic ... more Conclusions-Fe/Al ratios u The atomic ratio of Fe/Al in titanite from both volcanic and plutonic rocks is typically close to 1:1 and almost always >1:2. u Volcanic titanite compositions typically cluster more tightly in terms Fe, Al, and F than do titanite compositions from any other environment. u Fe/Al ratios in titanite from peralkaline silica-undersaturated volcanic and plutonic rocks are typically >1:1. u Titanite from metamorphic, hydrothermal, and pegmatitic environments scatter widely in Fe/Al. u Titanite from eclogite tends to have the lowest Fe/Al ratios, typically <1:8. Conclusions-Charge Balancing u Charge balance in metamorphic, hydrothermal, and pegmatitic titanite due to Fe +3 and Al +3 substitution into the Ti +4 site is largely accomplished by the coupled substitution of Ffor O-2. u However, in volcanic and plutonic titanite the charge imbalance due to Fe +3 and Al +3 substitution appears to be mainly coupled with REE +3 and Y +3 substitution into the Ca +2 site with a more minor contribution from Fsubstitution. u In Si-undersaturated rocks, substitution into the Ti +4 site by Nb +5 coupled with Fe +3 is a major factor in charge balancing.
Rock Canyon near Provo, Utah is an ideal outdoor laboratory. Th e
canyon has been known and explo... more Rock Canyon near Provo, Utah is an ideal outdoor laboratory. Th e canyon has been known and explored for many years by scientists and students for its fascinating geology, biology, and botany. It is also a favorite location for rock climbers, hikers, and other outdoor enthusiasts. Geology is the focal point of this beautiful canyon with a history that stretches from the Precambrian (about 700 million years ago) to the Wasatch fault and Lake Bonneville, which covered much of western Utah at its peak roughly 18,000 years ago. Excellent exposures of the rocks allow visitors to see features clearly and piece together the history of the canyon.
A history and genealogy of the descendants of David Duers (or Dewers) and Deborah Sherman includi... more A history and genealogy of the descendants of David Duers (or Dewers) and Deborah Sherman including the first 6 generations. The book includes many photos and stories.
Photos and letters written by Lieutenant R. T. Kowallis and his wife Norma Jensen Kowallis while ... more Photos and letters written by Lieutenant R. T. Kowallis and his wife Norma Jensen Kowallis while he was stationed in the Pacific during World War II in 1945. A higher resolution version of this book is available from the author upon request.
Copies of this book may be obtained from the Department of Geological Sciences, Brigham Young Uni... more Copies of this book may be obtained from the Department of Geological Sciences, Brigham Young University (contact: [email protected]).
This is a completely revised and updated version of the most widely used book on the geology of Utah in print. This book supplements the published geologic maps of Utah (Hintze, 1980, 1997, 2000f) by providing a third dimension, thickness, to the many map units whose areal extent is shown on the maps. The book also summarizes how these map units relate to Earth’s plate tectonic system. Much new information regarding Utah’s geologic past has been discovered in the the twenty-two years since the last edition of this book was published. Updates have been particularly striking in our understanding of plate tectonics, knowledge of Precambrian rocks, concepts and ages of volcanic events in the last 30 million years, documenting the history of Lake Bonneville within the last 30,000 years, and characterizing the activity of the Wasatch Fault within the last 5000 years. Fourteen new stratigraphic charts have been added and all of the text and figures, including the stratigraphic and correlation charts, have been completely revised. The book is directed primarily toward students in geology, but professional geologists working in Utah will find the stratigraphic and correlation charts useful, as well as the source literature citation list. Other interested persons will find the broad sweep of Utah’s geologic history fascinating.
The Uinta Mountains are an east-west-trending, reverse fault-bounded, basement-cored Laramide upl... more The Uinta Mountains are an east-west-trending, reverse fault-bounded, basement-cored Laramide uplift. The Eocene Duchesne River Formation and Oligocene Bishop Conglomerate represent late stage, intermontane basin fill of the Uinta Basin in northeastern Utah. Detailed mapping (1:24,000 scale), clast counts in conglomerate beds, description of lithology and stratigraphic contacts, and radiometric dating of pyroclastic fall beds of the Duchesne River Formation and Bishop Conglomerate in the Vernal NW quadrangle in northeastern Utah reveal stratal geometries of middle Cenozoic depositional units, the uplift and unroofing history of the eastern Uinta Mountains, and give evidence for the pulsed termination of Laramide uplift related to rollback of the Farallon slab and lithospheric delamination. These relationships show the continuation of Laramide uplift in this region until after 37.9 Ma and before 34 Ma, an age younger than the previously reported 45 to 40 Ma. The Duchesne River Format...
Textural and compositional variations in titanite constrain the roles of magma mixing and hydroth... more Textural and compositional variations in titanite constrain the roles of magma mixing and hydrothermal alteration in two plutons in central Utah: the Jurassic Notch Peak and the Oligocene Little Cottonwood stocks. In the Notch Peak intrusion, magmatic titanite grains usually have oscillatory zones combined with BSE-bright sector zones, in some cases surrounding simple unzoned cores. These grains are frequently overprinted by hydrothermal titanite with low concentrations of high field strength elements (HFSE). Magmatic titanite has an average δ18O of 6.0‰ and post-magmatic titanite is 6.2‰, as analyzed by SIMS. Average Zr-in-titanite temperatures are also similar, with 718 °C for magmatic and 711 °C for hydrothermal titanite. These observations indicate simple magmatic growth, followed by hydrothermal alteration by magmatic fluids. Titanite in aplite dikes and sills has lower concentrations of all trace elements except F. Many titanite grains in the aplites have late overgrowths of h...
Titanite is an accessory mineral in many granites. Due to its incorporation of a wide variety of ... more Titanite is an accessory mineral in many granites. Due to its incorporation of a wide variety of trace elements, low elemental diffusion rates, and relative abundance, titanite is useful in the study of petrogenetic processes. In addition, titanite also retains clear growth zoning from past events. We sampled titanite from two localities, the Notch Peak Granite located in Western Utah, and the Little Cottonwood stock located near Salt Lake City, Utah in order to evaluate Titanite textures in interpreting magmatic and hydrothermal histories.
The Miocene rhyolites of the Spor Mountain Formation host Earth's largest beryllium deposit, whic... more The Miocene rhyolites of the Spor Mountain Formation host Earth's largest beryllium deposit, which produced 85% of the world's beryllium in 2010. The fresh lava is extremely enriched in Be (up to 75 ppm in matrix glass). We have examined the rhyolite to better understand the Be enrichment. The Spor Mountain rhyolite contains ~40% quartz, ~40% sanidine, ~10% biotite, and ~10% plagioclase, along with accessory fluorite, columbite, euxenite, fergusonite, monazite, thorite, and zircon. Two types of rhyolite are present within the Spor Mountain Formation, a less-evolved magma (1150 ppm Rb, 42 ppm Be, 0.7 wt% F in glass) and a more-evolved magma (1710 ppm Rb, 75 ppm Be, 1.6 wt% F in glass). Eruption temperatures estimated using two-feldspar (
Geological Society of America Abstracts with Programs, 2018
Conclusions-Fe/Al ratios u The atomic ratio of Fe/Al in titanite from both volcanic and plutonic ... more Conclusions-Fe/Al ratios u The atomic ratio of Fe/Al in titanite from both volcanic and plutonic rocks is typically close to 1:1 and almost always >1:2. u Volcanic titanite compositions typically cluster more tightly in terms Fe, Al, and F than do titanite compositions from any other environment. u Fe/Al ratios in titanite from peralkaline silica-undersaturated volcanic and plutonic rocks are typically >1:1. u Titanite from metamorphic, hydrothermal, and pegmatitic environments scatter widely in Fe/Al. u Titanite from eclogite tends to have the lowest Fe/Al ratios, typically <1:8. Conclusions-Charge Balancing u Charge balance in metamorphic, hydrothermal, and pegmatitic titanite due to Fe +3 and Al +3 substitution into the Ti +4 site is largely accomplished by the coupled substitution of Ffor O-2. u However, in volcanic and plutonic titanite the charge imbalance due to Fe +3 and Al +3 substitution appears to be mainly coupled with REE +3 and Y +3 substitution into the Ca +2 site with a more minor contribution from Fsubstitution. u In Si-undersaturated rocks, substitution into the Ti +4 site by Nb +5 coupled with Fe +3 is a major factor in charge balancing.
Geological Society of America Abstracts with Programs,, May 12, 2009
A Miocene transition from subduction-related intermediate and silicic volcanism to extensional ma... more A Miocene transition from subduction-related intermediate and silicic volcanism to extensional mafic volcanism is recorded by volcanic rocks in the Allens Ranch quadrangle which lies at the northern end of the East Tintic Mountains west of Utah Lake near the eastern margin of the Great Basin of central Utah. The Paleogene volcanic section is dominated by a suite of high-K calc-alkaline extrusive rocks. The oldest is a rhyolite ignimbrite that we have correlated with the Packard Quartz Latite with a type-locality to the ...
Geological Society of America Abstracts with Programs, Nov 7, 2012
The Brushy Basin Member of the Morrison Formation contains numerous volcanic ash beds thought to ... more The Brushy Basin Member of the Morrison Formation contains numerous volcanic ash beds thought to have erupted from a Late Jurassic volcanic arc along the west coast of North America. These sediments were deposited in a back bulge basin during the Nevadan orogeny. Phenocrysts in 31 ash beds from a section near Huntington, Utah were studied to better understand magma compositions and infer the tectonic setting of the magmatism. Glass has altered to clay and zeolites, but phenocrysts are preserved, including: quartz, ...
Titanite is an important mineral in petrochronology studies. Understanding chemical signatures of... more Titanite is an important mineral in petrochronology studies. Understanding chemical signatures of titanite from different environments can provide significant data in unraveling the complex histories recorded in their textures and compositions. Using a database of over 8500 titanite analyses from both the literature (3829) and our own data (4900), we found that the ratio of Fe/Al is useful for separating igneous titanite (Fe/Al is typically close to 1:1 and almost always > 1:2) from metamorphic titanite (Fe/Al ratio is < 1:2) with few exceptions. Volcanic titanite grains can also be separated from plutonic titanite grains due to their shorter crystallization histories with compositions clustered more tightly in terms of Fe, Al, and F. Compositions of titanite from plutonic rocks often have later metamorphic or hydrothermal overgrowths that are not found on volcanic titanite. Fe/Al ratios in titanite from silica-undersaturated volcanic and plutonic rocks are typically > 1:2 ...
Titanite has become an important mineral in petrochronology studies. Understanding the chemical s... more Titanite has become an important mineral in petrochronology studies. Understanding the chemical signatures of titanite from different environments can provide significant help in unraveling the complex histories observed in many titanite grains. We have compiled a database of over 7000 titanite analyses from the literature and supplemented it with our own data. We find that the ratio of Fe/Al is useful for separating volcanic and plutonic titanite (Fe/Al typically close to 1:1 and almost always >1:2) from metamorphic titanite (Fe/Al ratio is <1:2) with a few exceptions. Volcanic titanites can also be separated from plutonic titanites due to their shorter crystallization histories causing them to cluster more tightly in terms of their Fe, Al, and F. Compositions of titanite from plutonic rocks are typically more scattered than volcanic titanite suggesting longer histories of crystallization and, in many cases, later metamorphic or hydrothermal overgrowths that are not found on volcanic titanite. Fe/Al ratios in titanites from silica-undersaturated volcanic and plutonic rocks (phonolites, nepheline syenites, ijolites, etc.) are typically >1:2 and include titanite with the highest Fe/Al values. Although they overlap the field for normal volcanic and plutonic titanite, other elements (particularly high levels of Nb and low levels of Y) allow them to be separated. In most metamorphic rocks the Fe/Al ratio is <1:2 with the exception of a few metamorphic titanites that formed in mafic rocks, such as those from metabasalts or metabasites. Titanite from high pressure metamorphic rocks (eclogites, blue schists, etc.) tend to have the lowest Fe/Al ratios, typically <1:8. Titanite from hydrothermal and pegmatitic environments scatter widely in terms of Fe/Al even within single grains due to crystallization from fluids with highly variable compositions. Charge balancing in metamorphic, hydrothermal, and pegmatitic titanite due to Fe+3 and Al+3 substitution into the Ti+4 site is largely accomplished by the coupled substitution of F- for O-2. However, in volcanic and plutonic titanite the charge imbalance due to Fe+3 and Al+3 substitution appears to be mainly coupled with REE+3 or Y+3 substitution into the Ca+2 site with a more minor contribution from F-.
Annual Geological Society of America Meeting 2018, Indianapolis, Indiana
Titanite has become an i... more Annual Geological Society of America Meeting 2018, Indianapolis, Indiana Titanite has become an important mineral in petrochronology studies. Understanding the chemical signatures of titanite from different environments can provide significant help in unraveling the complex histories observed in many titanite grains. We have compiled a database of over 7000 titanite analyses from the literature and supplemented it with our own data. We find that the ratio of Fe/Al is useful for separating volcanic and plutonic titanite (Fe/Al typically close to 1:1 and almost always >1:2) from metamorphic titanite (Fe/Al ratio is <1:2) with a few exceptions. Volcanic titanites can also be separated from plutonic titanites due to their shorter crystallization histories causing them to cluster more tightly in terms of their Fe, Al, and F. Compositions of titanite from plutonic rocks are typically more scattered than volcanic titanite suggesting longer histories of crystallization and, in many cases, later metamorphic or hydrothermal overgrowths that are not found on volcanic titanite. Fe/Al ratios in titanites from silica-undersaturated volcanic and plutonic rocks (phonolites, nepheline syenites, ijolites, etc.) are typically >1:2 and include titanite with the highest Fe/Al values. Although they overlap the field for normal volcanic and plutonic titanite, other elements (particularly high levels of Nb and low levels of Y) allow them to be separated. In most metamorphic rocks the Fe/Al ratio is <1:2 with the exception of a few metamorphic titanites that formed in mafic rocks, such as those from metabasalts or metabasites. Titanite from high pressure metamorphic rocks (eclogites, blue schists, etc.) tend to have the lowest Fe/Al ratios, typically <1:8. Titanite from hydrothermal and pegmatitic environments scatter widely in terms of Fe/Al even within single grains due to crystallization from fluids with highly variable compositions. Charge balancing in metamorphic, hydrothermal, and pegmatitic titanite due to Fe+3 and Al+3 substitution into the Ti+4 site is largely accomplished by the coupled substitution of F- for O-2. However, in volcanic and plutonic titanite the charge imbalance due to Fe+3 and Al+3 substitution appears to be mainly coupled with REE+3 or Y+3 substitution into the Ca+2 site with a more minor contribution from F-.
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Books by Bart Kowallis
canyon has been known and explored for many years by scientists
and students for its fascinating geology, biology, and botany. It is
also a favorite location for rock climbers, hikers, and other outdoor
enthusiasts. Geology is the focal point of this beautiful canyon with a history that stretches from the Precambrian (about 700 million years ago) to the Wasatch fault and Lake Bonneville, which covered much of
western Utah at its peak roughly 18,000 years ago. Excellent
exposures of the rocks allow visitors to see features clearly and piece together the history of the canyon.
This is a completely revised and updated version of the most widely used book on the geology of Utah in print. This book supplements the published geologic maps of Utah (Hintze, 1980, 1997, 2000f) by providing a third dimension, thickness, to the many map units whose areal extent is shown on the maps. The book also summarizes how these map units relate to Earth’s plate tectonic system. Much new information regarding Utah’s geologic past has been discovered in the the twenty-two years since the last edition of this book was published. Updates have been particularly striking in our understanding of plate tectonics, knowledge of Precambrian rocks, concepts and ages of volcanic events in the last 30 million years, documenting the history of Lake Bonneville within the last 30,000 years, and characterizing the activity of the Wasatch Fault within the last 5000 years. Fourteen new stratigraphic charts have been added and all of the text and figures, including the stratigraphic and correlation charts, have been completely revised. The book is directed primarily toward students in geology, but professional geologists working in Utah will find the stratigraphic and correlation charts useful, as well as the source literature citation list. Other interested persons will find the broad sweep of Utah’s geologic history fascinating.
Papers by Bart Kowallis
canyon has been known and explored for many years by scientists
and students for its fascinating geology, biology, and botany. It is
also a favorite location for rock climbers, hikers, and other outdoor
enthusiasts. Geology is the focal point of this beautiful canyon with a history that stretches from the Precambrian (about 700 million years ago) to the Wasatch fault and Lake Bonneville, which covered much of
western Utah at its peak roughly 18,000 years ago. Excellent
exposures of the rocks allow visitors to see features clearly and piece together the history of the canyon.
This is a completely revised and updated version of the most widely used book on the geology of Utah in print. This book supplements the published geologic maps of Utah (Hintze, 1980, 1997, 2000f) by providing a third dimension, thickness, to the many map units whose areal extent is shown on the maps. The book also summarizes how these map units relate to Earth’s plate tectonic system. Much new information regarding Utah’s geologic past has been discovered in the the twenty-two years since the last edition of this book was published. Updates have been particularly striking in our understanding of plate tectonics, knowledge of Precambrian rocks, concepts and ages of volcanic events in the last 30 million years, documenting the history of Lake Bonneville within the last 30,000 years, and characterizing the activity of the Wasatch Fault within the last 5000 years. Fourteen new stratigraphic charts have been added and all of the text and figures, including the stratigraphic and correlation charts, have been completely revised. The book is directed primarily toward students in geology, but professional geologists working in Utah will find the stratigraphic and correlation charts useful, as well as the source literature citation list. Other interested persons will find the broad sweep of Utah’s geologic history fascinating.
Titanite has become an important mineral in petrochronology studies. Understanding the chemical signatures of titanite from different environments can provide significant help in unraveling the complex histories observed in many titanite grains. We have compiled a database of over 7000 titanite analyses from the literature and supplemented it with our own data. We find that the ratio of Fe/Al is useful for separating volcanic and plutonic titanite (Fe/Al typically close to 1:1 and almost always >1:2) from metamorphic titanite (Fe/Al ratio is <1:2) with a few exceptions. Volcanic titanites can also be separated from plutonic titanites due to their shorter crystallization histories causing them to cluster more tightly in terms of their Fe, Al, and F. Compositions of titanite from plutonic rocks are typically more scattered than volcanic titanite suggesting longer histories of crystallization and, in many cases, later metamorphic or hydrothermal overgrowths that are not found on volcanic titanite. Fe/Al ratios in titanites from silica-undersaturated volcanic and plutonic rocks (phonolites, nepheline syenites, ijolites, etc.) are typically >1:2 and include titanite with the highest Fe/Al values. Although they overlap the field for normal volcanic and plutonic titanite, other elements (particularly high levels of Nb and low levels of Y) allow them to be separated. In most metamorphic rocks the Fe/Al ratio is <1:2 with the exception of a few metamorphic titanites that formed in mafic rocks, such as those from metabasalts or metabasites. Titanite from high pressure metamorphic rocks (eclogites, blue schists, etc.) tend to have the lowest Fe/Al ratios, typically <1:8. Titanite from hydrothermal and pegmatitic environments scatter widely in terms of Fe/Al even within single grains due to crystallization from fluids with highly variable compositions. Charge balancing in metamorphic, hydrothermal, and pegmatitic titanite due to Fe+3 and Al+3 substitution into the Ti+4 site is largely accomplished by the coupled substitution of F- for O-2. However, in volcanic and plutonic titanite the charge imbalance due to Fe+3 and Al+3 substitution appears to be mainly coupled with REE+3 or Y+3 substitution into the Ca+2 site with a more minor contribution from F-.