Elizabeth J. Catlos

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• PhD
• Professor (Associate) at University of Texas at Austin

Pressure‐temperature (P‐T) conditions and high‐resolution paths from eleven garnet‐bearing rocks collected across Himalayan fault systems exposed along the Bhagirathi River (Uttarakhand, NW India) reveal the tectonic conditions responsible for their growth. A garnet from the Tethyan metasedimentary unit has a 50.3±0.6 Ma (Th‐Pb, ±1σ) monazite inclu...

The Sikkim region of the Himalayas (NE India) may form an important microplate between Nepal and Bhutan. Here we report high-resolution pressure-temperature (P-T) paths taken from garnet-bearing rocks across the northern and eastern portion of the region’s Main Central Thrust (MCT) shear zone. The MCT separates units affiliated with the Greater Him...

The Hellenic arc, where the African (Nubian) slab subducts beneath the Aegean and Anatolian microplates, is a type-locality for understanding subduction dynamics. The subducting African slab is the driver for extension in the Aegean and Anatolian microplates and plays a significant role in accommodating the Anatolian microplate's westward extrusion...

The Himalayan orogen exposes assemblages from low-grade Indian shelf sediments of the Tethyan Formation to eclogite and ultra-high-pressure rocks from the suture zone between the Indian craton and Asian subcontinent. Barrovian-grade pelites in the Himalayan core comprise the Greater Himalayan Crystallines and Lesser Himalayan formations. These unit...

The Spongtang ophiolite (Ladakh, NW India) constrains the nature of oceanic lithosphere before Indo-Asia collision and key stages in the development of the Himalayas. We report whole-rock ⁴⁰ Ar/ ³⁹ Ar and in situ zircon ²³⁸ U– ²⁰⁶ Pb ages from its crustal and upper and lower mantle sequences. Major and trace elements from harzburgite minerals sugge...

Divergent mid-Silurian (late Wenlock) and latest Silurian–earliest Devonian (Pridoli–Lochkovian) ages have been proposed for the strata bearing the millipede Pneumodesmus newmani, the oldest known undoubted air-breathing land animal, marking a significant event in the evolution of the first land biota. The late Wenlock age is based on physically co...

The transition of vertebrates from aquatic to terrestrial environments during the late Devonian to early Carboniferous marks a crucial evolutionary milestone. However, this transition remains poorly understood due to a scarcity of early tetrapod fossils during the late Devonian to early Mississippian, creating a gap in the fossil record known as Ro...

The study of extensional tectonics harkens to the early days of plate tectonics, as the search for mechanisms driving large continental blocks to drift apart led to advances in paleomagnetism and geochronology. Divergent plate boundaries form extensive and continuous volcanic systems covering large portions of the Earth and are fundamental to under...

The North American Cordilleran metamorphic core complex belt provides insight into the tectonometamorphic evolution of North America. Garnet-bearing assemblages have been used to generate pressure-temperature (P-T) constraints on the metamorphic history in its northern and central segments. Such datasets are scarce in its southern segment. We revie...

Transfer zones, locations where strain is transferred from one structural element to another, are common features in the Aegean and Anatolian microplates. These features link fault systems and accommodate broader-scale tectonic processes in the area, including the extrusion of the microplates and extension driven by the rollback of the African (Nub...

Western Anatolia, at the boundary between the Aegean and Anatolian microplates, is considered a type-location for the significant transition between compressional and extensional tectonics. The region is marked by diverse tectonic events from the Paleoproterozoic through the Cambrian, Devonian, and Late Cretaceous, recorded by its suture zones, met...

Divergent mid-Silurian (late Wenlock) and latest Silurian-earliest Devonian (Pridoli-Lochkovian) ages have been proposed for the strata bearing the millipede Pneumodesmus newmani, the first recorded undoubtedly air-breathing land animal, marking a significant event in the evolution of the first land biota. The late Wenlock age is based on physicall...

Lineaments have long been enigmatic features of the Himalayan orogen, often regarded as potential but poorly understood tectonic structures. The Mw 7.8 25 April 2015 Gorkha earthquake renewed attention to lineaments as two (Judi and Gaurisankar) may have influenced its rupture dynamics. Using ArcGIS and earthquake data since 1990, we tested the hyp...

The Precambrian basement topography of the Indo-Gangetic plain has significantly shaped its depositional processes, marking the locations of major tectonic features directly south of the Himalayas. These basement tectonic features (from west to east) include the Sargodha-Lahore-Delhi Ridge, Aravalli-Delhi massif, Delhi-Hardiwar Ridge, Faizabad Ridg...

Himalayan garnet-bearing rocks have long been used to unravel subsurface pressure-temperature (P-T) conditions and paths, aiding in developing models for its tectonic history. However, garnets currently outcropped in the Himalayan hinterland were only recently exposed to the surface. Our knowledge of Himalayan development is thus fundamentally limi...

The emergence of vascular plants, such as Cooksonia, had a profound impact on Earth’s Early Paleozoic biogeochemical cycles (e.g. atmospheric oxygen, nitrogen and CO2), potentially triggering global environmental and biological changes. However, the timing of Cooksonia’s terrestrial emergence remains elusive as phylogenetic models, microfossils and...

As technological advances continue, the demand for Rare Earth elements (REEs) and other critical minerals has surged due to their essential applications in technology, energy, and national security. These elements have become some of the most valuable non-renewable resources in our modern society. However, the increasing depletion of certain elemen...

The Slate Islands (Ontario) is one of Canada's larger impact structures at 32 km in diameter and has been linked to the Ordovician meteorite event (OME). We report zircon U–Pb dates from two suevite and two syenite samples collected from the Slate Islands. Plagioclase ⁴⁰ Ar/ ³⁹ Ar dates were also obtained from one of the samples. The plagioclase an...

Himalayan evolution in the sands of time: Geochemical analysis of Siwalik garnets (Nepal). 2023 AGU Fall Meeting, San Francisco, CA, 11-15 Dec. https://agu.confex.com/agu/fm23/meetingapp.cgi/Paper/1432781

The Sikkim region of NE India plays a central role in developing ideas regarding the development of the Himalayan range. The region may form a microplate between Nepal and Bhutan. Here, the convergence vector is almost perpendicular to the Himalayan deformation front. Convergence is estimated to be ~450 km and is accommodated by the Main Central Th...

Some of the earliest stages of the Himalayan orogeny are recorded in Siwalik formation foreland basin sediments. We aim to understand the uplift and exhumation of the Himalayas recorded in the sedimentary record of Siwalik sandstones by exploiting compositional variations recorded by its detrital garnets. Garnet (Mg,Fe,Mn,Ca)3(Al2Si3O12) is conside...

Sedimentary rocks exposed at Dob's Linn, Scotland, have significantly influenced our understanding of how life evolved over the Ordovician to Early Silurian. The current interpreted chronostratigraphic boundary between the Ordovician and Silurian periods is a Global Boundary Stratotype Section and Point (GSSP), calibrated to 443.8 ± 1.5 Ma (Hirnati...

The Carpathian Mountains form the large collisional orocline stretching from Vienna, Austria to Bucharest, Romania. The Inner Western Carpathians include the High Tatra mountains, which feature the highest elevation peaks. Here we studied the exhumation history of an area east of Gerlachovský štít, the topographically highest point of the High Tatr...

Pore-fluid pressure is a key factor controlling the stress state and rock failure in Earth’s crust. Although its role in brittle deformation in the shallow crust (< 1-3 km) has been extensively examined, and in some cases quantified by direct bore-hole measurements, how pore-fluid pressure affects crustal deformation at brittle-ductile-transition d...

The evolution of vascular plants like Cooksonia likely increased weathering rates, soil development, and modified Earth's biogeochemical cycles (e.g., atmospheric oxygenation and the carbon cycle), which influenced climate and terrestrial ecosystems during the Early Paleozoic. These changes may have had an impact on global events such as the Great...

The Carpathian Mountains form the large collisional orocline stretching from Vienna, Austria to Bucharest, Romania. The Western and Inner Carpathians include the High Tatra mountains, which exhibit the highest elevation peaks of the entire mountain belt. Here we studied the exhumation history of an area near Gerlachovský štít, the topographically h...

The High Tatra Mountains (HTM) in northern Slovakia represent an anomalous uplifted portion of basement in the Western Carpathians and offer an excellent opportunity to study arcuate orogenesis, deep crust exhumation, and the transition between thin-skinned shortening and basement-involved transcurrent deformation as the HTM is comprised of large g...

Compressional and contractional tectonics are of interest to various researchers, from rock mechanics and engineering to those studying the hazards, dynamics, and evolution of plate boundaries. We summarize here the terminology regarding deformation associated with compressional and contractional tectonics. We describe the now largely discarded geo...

The Western and High Tatra Mountains (northern Slovakia, southern Poland) contain the best-exposed rocks record within the Carpathian orogenic belt. Petrological, geochemical, and geochronological data from granitic assemblages across the Western (n = 1) and High Tatra Mountains (n = 19) were used to understand how they responded to an extended tec...

Since the wide acceptance of Plate Tectonics Theory in the 1970s, our understanding of Extensional Tectonics from Continental Breakup to Formation of Oceanic Basins has improved substantially based on geological, geophysical, geochemical studies, and analog and computer modeling. Although it is widely accepted that oceanic basins initiate during th...

The Western and High Tatra Mountains (northern Slovakia, southern Poland) contain the best- exposed rocks record within the Carpathian orogenic belt. They are a logical location to study arcuate orogenesis, exhumation rates of the deep crust, and magnitudes and rates involved in the transfer of heat and mass during mountain-building events. Underst...

The Carpathian Mountains form the large collisional orocline stretching from Vienna, Austria to Bucharest, Romania. The Western and Inner Carpathians include the High Tatra mountains, which exhibit the highest elevation peaks of the entire mountain belt. Here we studied the exhumation history of an area near Gerlachovský štít, the topographically h...

In contrast to the ‘propaganda’ of the currently dominant vertebrates (i.e. us), arthropods not amphibians were the first land animals. And like many another great advance, they first appeared in Scotland. The first land animals were ‘millipedes’, which evolved with the first true land plants at the edges of Scottish mountain lakes about 425 Ma. Fr...

Re-assessing the Parakidograptus acuminatus biozone age using U-Pb zircon dates at Dob's Linn, Scotland. Sample closest to the Ordovician-Silurian boundary located in the Parakidograptus acuminatus biozone yields 2/3 zircon grains with a CA-ID-TIMS Maximum Depositional Age (MDA): 449±0.8 Ma. The results assign the Parakidograptus acuminatus biozone...

Dob's Linn (Scotland) is a location that has significantly influenced our understanding of how life evolved over the Ordovician to early Silurian. The current chronostratigraphic boundary between the Ordovician and Silurian periods is a Global Boundary Stratotype Section and Point (GSSP) at Dob's Linn calibrated to 443.8±1.5 Ma, partly based on bio...

Barrovian-grade pelites in the Greater Himalayan Crystallines and Lesser Himalayan Formations are exposed in the Himalayan core are separated by the Main Central Thrust (MCT). This fault system accommodated a significant amount of India-Asia convergence and is the focus of several models that explore ideas about the development of the range and col...

One of the most important factors controlling the stress state and rock failure in Earth’s crust is pore-fluid pressure. Although its role in brittle deformation in the shallow crust (< 1-3 km) has been extensively examined, and in some cases quantified by direct bore-hole measurements, how pore-fluid pressure affects crustal deformation at brittle...

The garnet chemical zoning method (GZM) is a reliable thermodynamic approach for forward modeling pressure-temperature (P-T) paths using observed garnet and bulk rock compositions. However, intracrystalline diffusion is known to compromise the integrity of GZM modeled garnet-growth P-T paths. For this reason, extracting reliable metamorphic estimat...

The Menderes Massif in western Turkey has global importance due to its role as the largest zone of active continental extension on Earth. The region is located at the boundary between the Aegean and Anatolian microplates and is considered a type-location for marking a significant transition between contractional and extensional tectonics across the...

Collisional tectonics preceded large-scale extension and metamorphic core complex formation In the Basins and Ranges of North America and the Aegean region of Eastern Europe. It occurred during the Cretaceous Sevier Orogeny in the Basin and Ranges and still continues to the NE of the region. In the Aegean region, collisional tectonics occurred duri...

United States Deciphering the assembly of the Aegean and Anatolian microplates and their past and present-day deformation drivers impacts our understanding of continental tectonics, subduction zone processes, lithospheric deformation, ore generation process, and hazards. Several units and structures can be correlated from Western Anatolia to the Ae...

The Hellenic arc, where the African (Nubian) slab subducts beneath the Aegean and Anatolian microplates, has emerged as a type-locality for understanding subduction dynamics, including slab tear, slab fragments, drips, and transfer zones. Based on field evidence and geophysical, tectonics, and geochemical studies, it has been recognized that the su...

Western Anatolia is located at the boundary between the Aegean and Anatolian microplates. It is considered a type-location for marking a significant transition between compressional and extensional tectonics across the Alpine-Himalayan chain. The onset of lateral extrusion in Western Anatolia and the Aegean during the Eocene is only one of its tran...

The Himalayan orogen exposes a range of metamorphosed assemblages, from low-grade Indian shelf sediments of the Tethyan Formation to eclogite and ultra-high pressure rocks documented near the suture zone between the Indian craton and Asian subcontinent. Barrovian-grade pelites and mafic protoliths are exposed in the Himalayan core and include the G...

The development of the NW Gondwanan Lower Paleozoic passive margin requires accurate dating of its Cambro-Ordovician rocks. In northern Portugal, major bimodal volcanism associated with rifting during the Cambrian to earliest Ordovician is poorly constrained biostratigraphically. To contribute to resolving the ages of these rocks, we dated zircons...

This study presents geochemical and geochronological data from rock samples collected from the Western Carpathian mountains, eastern Slovakia. Granite assemblages that intrude the Gemeric and Veporic Superunits were imaged using a petrographic microscope to determine rock textures and their mineral assemblages. Zircon grains from seven individual p...

The Gemeric and Veporic Superunits of the Western Carpathians correlate to the Lower and Middle Austroalpine tectonic units (nappes) of the Eastern Alps. The Gemeric Superunit is characterized by small exposures of rare-metal granites, and their ages impact understanding its tectonic history and how this portion of the Carpathians relates to other...

Tectonic models as a universal outcome generate predictions regarding the travel-time paths of rocks as they displace due to the application of particular input parameters and boundary conditions. A need for most of these models, either as a constraint for realistic input conditions or to gauge their relevance to a particular natural system, is pre...

The end of the Ordovician marks one of the greatest of the Earth's mass extinctions. One hypothesis explains this mass extinction as the result of a short-lived, major glaciation preceded by episodes of increased volcanism brought on by the Taconic orogeny. K-bentonites (weathered tephras), provide evidence for this volcanism. However, there is a l...

The Menderes Massif (Turkey) is a metamorphic core complex that records Alpine crustal shortening and extension. Here, nine garnet-bearing schist samples in the Central Menderes Massif (CMM) from below the Alaşehir detachment (AD) were studied to reconstruct their growth history. P-T estimates made using a chemical zoning approach, and petrological...

The Menderes Massif (Turkey) is a metamorphic core complex that records Alpine crustal shortening and extension. Here nine garnet-bearing schists samples in the Central Menderes Massif (CMM) from below the Alaşehir detachment (AD) have been studied to reconstruct their growth history. P-T estimates made using a chemical zoning approach, and petrolo...

The Ludlow Bone Bed (Welsh Basin) is a critical stratigraphic horizon and contains a rich assemblage of fish scales. Units above provide insights into the early evolution of animal and plant life. The bed has not yet been radioisotopically dated. Here, we report 207 secondary ion mass spectrometry (SIMS) ages from 102 zircon (ZrSiO 4 ) grains from...

Monazite [(Ce, Th)PO4] from a pegmatite in the Morefield Mine of the eastern Piedmont of central Virginia is used as an age standard but has unusually high and variable amounts of common Pb. Common Pb has led to problems for dating applications, interpretations regarding the significance of its age, and how it relates to nearby granite intrusions a...

Slovakia is located within the Central Western Carpathians (CWC), one of many connected curved mountain belts prominent throughout the Mediterranean area and Europe. It is divided into tectonic domains considered “superunits,” termed the Gemeric, Veporic, and Tatric that correlate to the lower, middle, and upper Austoalpine nappes. For example, gra...

Molecular clock calculations suggest a late Cambrian (~ 500 Ma) divergence of myriapod classes. Yet, the earliest myriapods only appear in the latest Silurian (~425 Ma). 75 million years later; though correlation with the standard marine-based geological time scale is difficult. We radiometrically dated (U/Pb method) zircons in sediments at 3 sites...

Molecular clock calculations suggest a late Cambrian (~500 Ma) divergence of myriapod classes. Yet, the earliest myriapods only appear in the latest Silurian (~425 Ma). 75 million years later; though correlation with the standard marine-based geological time scale is difficult. We radiometrically dated (U/Pb method) zircons in sediments at 3 sites...

For the past two years, The University of Texas at Austin Jackson School of Geosciences (JSG) has hosted an annual Enhancing Diversity in Geoscience Graduate Education (EDGE) Graduate School Preview. The two-day event is designed to encourage U.S. citizens and permanent residents traditionally underrepresented in the geosciences to apply. Selected...

Slovakia is located within the Central Western Carpathians (CWC), one of many connected curved mountain belts prominent throughout the Mediterranean area and Europe. Its geology is divided into tectonic domains considered “superunits,” termed the Gemeric, Veporic, and Tatric that correlate to the lower, middle, and upper Austoalpine nappes. The Gem...

T42B-02 presented at 2019 AGU Fall Meeting, San Francisco, CA 9-13 Dec. Garnet-bearing rocks have long been recognized as geochemical recorders of pressure-temperature (P-T) conditions that lend key insight into large-scale tectonic processes. The Menderes Massif of western Turkey, Earth's type-locality of a metamorphic core complex, exemplifies a...

Evidence of syntectonic magmatism associated with onset extension and unroofing of the Menderes Massif metamorphic core complex, western Turkey, is well documented. The Salihli and Turgutlu plutons, located along the Alasehir detachment in the Central Menderes Massif (CMM) and the Koyunoba and Eğrigöz Plutons located in the Northern Menderes Massif...

Approximately 470 million years ago, the breakup of the L-Chondrite Parent Body led to an increase in the amount of extraterrestrial material being delivered to Earth. Studies from Sweden have identified the long lasting (~20-50 my) nature of this Ordovician Meteorite Event (OME), while studies from China and Russia have confirmed it as a global oc...

A fundamental question in our understanding of how life appeared and transformed on this planet regards when critical sedimentary sections that record biotic changes in Earth's history were deposited. Sedimentary rocks exposed in Scotland and the Wales of the UK hold this information in their paleontology and geochronology, which help us decipher t...

The Menderes Massif, Turkey, is a type locality for deciphering the plate tectonic response from collision‐ to extension‐driven exhumation. Conventional thermobarometry and garnet pressure‐temperature (P‐T) paths from isochemical phase diagrams were calculated across a major fault (Selimiye Shear Zone, SSZ) bounding the southern edge of the Mendere...

Etzel, T.M. (2018) Modeling High-Resolution Pressure-Temperature Paths Across the Himalayan Main Central Thrust (Central Nepal): Implications for the Dynamics of Collision. Abstract V23B-06 presented at 2018 AGU Fall Meeting, Washington, D.C., 10-14 Dec. Plain Language Summary: The Main Central Thrust (MCT) is a major Himalayan fault system largely...

Geologic history of the Menderes Massif (MM), western Turkey is difficult to discern, partly due to a series of collisional and extensional events, each imparting a deformation fabric and, in some cases, producing recrystallization of prograde metamorphic minerals. To avoid recrystallization effects, we focused on garnet crystals, which commonly re...

2018) Deciphering the exhumation history of the crystalline core of the Himalayas: new insight from garnet-bearing assemblages (invited). Abstract (T43C-04) presented at 2018 AGU Fall Meeting, Washington, D.C., 10-14 Dec. The Greater Himalayan Crystallines (GHC) unit comprises a large portion of the Himalayan range and dominates much of its exposur...

Garnet-based pressure-temperature (P-T) paths have long been used to constrain tectonic models. Many of these models commonly focus on higher T tectonic processes, as garnets record how distinct packages are displaced by large-scale fault systems, for example. However, Theriak-Domino-based thermodynamic modeling now offers new possibilities to incr...

The Slate Islands Archipelago is the remnants of a highly eroded impact structure in Lake Superior. Although it’s origin as a meteorite crater is well established, the timing of this impact has not been identified. Numerous potential dates have been suggested for the impact, ranging from 1.1 Ga to 282 Ma. More importantly, it has been suggested tha...

High-resolution, garnet-based pressure-temperature (P-T) paths were obtained for nine rocks across the Himalayan Main Central Thrust (MCT) (Marsyangdi River transect, central Nepal). Paths were created using garnet and whole rock compositions as input parameters into a semiautomated Gibbs free-energy-minimization technique. The conditions recorded...

The focus of this contribution is constraining the timing of the tectonic evolution of the High Tatra Mountains in Slovakia, which are located in the Western Carpathian Mountains. Both monazite (REEThPO4) and zircon (ZrSiO4) grains were dated in rock thin section from the same samples of High Tatra granitoids to understand not only the tectonic evo...

The High Tatra Mountains of northern Slovakia are a prominent segment of the western Carpathian Mountain Belt. The range consists of polygenetic Variscan granitoid plutons emplaced during the closure of the Rheic Ocean (e.g., Gawęda et al. 2016). While crystallization is known to have occurred between ~340 Ma and ~370 Ma, uncertainties remain regar...

Monazite [(Ce,Th)PO4] is commonly reported to contain low amounts of common Pb and thus is ideal for U‐Th‐Pb geochronology. However, the Llallagua tin ore deposit in Bolivia and a pegmatite in the Amelia mining district of Virginia have monazite with unusually large and variable amounts of bulk abundance of common Pb or percentage of common to radi...

Geochronology and isotope (Sr, Nd and Pb) geochemistry of the Oligocene intrusions and associated hydrothermal mineralization in the northeast of Yenice, NW Turkey

Monazite [(Ce,Th)PO4] from the Llallagua tin ore deposit in Bolivia is characterized by low radiogenic element contents. Previously reported field evidence and mineral associations suggest the mineral formed via direct precipitation from hydrothermal fluids. Monazite compositions thus may provide insight into characteristics of the fluids from whic...

The oldest-known air-breathing land animal is the millipede Pneumodesmus newmani, found in the Cowie Harbour Fish Bed at Stonehaven, Scotland. Here we report the youngest, most concordant ²³⁸U-²⁰⁶Pb zircon age from ash below the fish bed of 413.7±4.4 Ma (±2σ), whereas the youngest age from a tuffaceous sandstone above the fish bed is statistically...

Six limestone assemblages along the North Anatolian Fault (NAF) Niksar pull-apart basin in northern Turkey were analyzed for δ¹⁸OPDB and δ¹³CPDB using bulk isotope ratio mass spectrometry (IRMS). Matrix-vein differences in δ¹⁸OPDB (−2.1 to 6.3‰) and δ¹³CPDB (−0.9 to 4.6‰) suggest a closed fluid system and rock buffering. Veins in one travertine and...

The Main Central Thrust (MCT) is the dominant crustal thickening structure in the Himalayas, juxtaposing high-grade Greater Himalayan Crystalline rocks over the lower-grade Lesser Himalaya Formations. The fault is underlain by a 2 to 12-km-thick sequence of deformed rocks characterized by an apparent inverted metamorphic gradient, termed the MCT sh...

The end of the Ordovician marks one of the greatest of the Earth’s mass extinctions. One hypothesis explains this mass extinction as the result of a short-lived, major glaciation preceded by episodes of increased volcanism brought on by the Taconic orogeny. K-bentonites, weathered volcanic ash, provide evidence for increased volcanism. However, the...

The Menghai batholith (Yunnan Province, China) is the southern extension of the ~370 km long Lincang granite body that syntectonically intruded the collisional zone between Gondwana (Baoshan block) and Laurasia (Simao block) terranes during closure of the Palaeo-Tethyan Ocean. Eight Menghai granodiorites were analysed across an ~45 km E–W transect...

Garnet-based thermobarometry is often used to develop models for the evolution of the central Menderes Massif, a large-scale metamorphic core complex in western Turkey. Menderes Massif P-T conditions constrain processes that worked to assemble western Turkey and link the massif to core complexes in the Aegean region. Here we report P-T conditions f...

The oldest air-breathing land animal found to date, the millipede Pneumodesmus newmani, was found in the Cowie harbour fish bed at Cowie, Aberdeenshire, Scotland. Despite it’s importance for concepts of land colonization, its age is debatable as the fossil occurs in a tectonically isolated, non-marine succession that is difficult to correlate with...

In response to the devastation caused by the 25 April 2015 MW 7.9 Nepal (Gorkha) earthquake and its aftershocks, the Geological Society of America convened an interdisciplinary session at its 2015 Annual Meeting in Baltimore. The forum allowed researchers from diverse disciplines to exchange information and develop meaningful paths toward reducing...

Monazite [(Ce,Th)PO4] from a pegmatite in the Morefield Mine of the eastern Piedmont of central Virginia has unusually high and variable amounts of common Pb, leading to problematic interpretations of its U-Th-Pb ages and how the monazite relates to nearby granite intrusions and faults. To address these issues, we analyze a single large monazite gr...

The end of the Ordovician marks one of the greatest of the Earth’s mass extinctions. One hypothesis explains this mass extinction as the result of a short-lived, major glaciation preceded by episodes of increased volcanism brought on by the Taconic orogeny. K-bentonites from many localities around the world provide evidence for increased volcanism....

The Nemazgah pluton, located in the Biga Peninsula of western Turkey, is a Miocene in age tourmaline bearing leucocratic porphyry formed in response to either subduction migration along the Hellenic arc or wide spread extension due to the closure of the Vardar Ocean. The Namazgah pluton is a high K–alkali, peraluminous, I type granitoid with a comp...

The Nemazgah pluton, located in the Biga Peninsula of western Turkey, is a Miocene in age tourmaline bearing leucocratic porphyry formed in response to either subduction migration along the Hellenic arc or wide spread extension due to the closure of the Vardar Ocean. Zoned tourmalines appear in acicular clusters and as larger columnar crystals with...