The December 2010 Lithosphere issue presents various studies on tectonic histories, fault activity, and mantle deformation. Researchers analyze the Llano Uplift in Texas, the Kern Canyon fault in California, and the Twin Sisters ultramafic body in Washington State, among other locations.
A team of geophysicists led by Harry Green at UC Riverside presents evidence contradicting the widely-held view that large amounts of water are carried to the deep mantle in subducting slabs. The study suggests that these slabs are essentially dry, with no pathway for significant amounts of water to enter the lower mantle.
Scientists have used a new seismic method to investigate the collision process between India and Tibet, revealing a more pronounced boundary between rigid lithosphere and softer asthenosphere. The study provides insights into the processes involved in the collision and aims to reduce earthquake risk in the region.
Researchers examine how silicic magma contributes to continental crust growth, the dynamics of the Tibetan Plateau's formation, and the nature of earthquakes in the Eastern Carpathians. New data suggest that continental delamination may be responsible for seismic activity in this region.
Researchers use seismic technique to detect boundary between old and new lithosphere beneath the North American continent. The study reveals a layer cake of ancient rock on top of newer material, challenging traditional theories on continental formation.
This article explores various geological phenomena, including the origin of rhyolites from South Mountain, Pennsylvania, growth faults in the Kaiparowits Basin, Utah, and extension of the Anaconda metamorphic core complex. The studies provide new information on volcanic magmas, tectonic deformation, and Earth's crust behavior.
Researchers have discovered an active strike-slip fault on the island of Trinidad, highlighting a major seismic hazard. The study also found that the lower crust is significantly weaker than the mantle at the Moho, and K/U ratio in the mantle records a snapshot of early Earth weathering.
Researchers present new slip rate estimates for the Alpine fault near Inchbonnie, New Zealand, yielding dextral, vertical, and reverse-slip rates of ~13.6, ~3, and ~3.4 mm/yr. These values have important implications for understanding plate boundary kinematics and comparing short-term strain with medium-term geologic rates.
Researchers are working together to understand intraplate earthquakes in an effort to minimize the loss of life and property. By deploying seismic recorders and analyzing data from two large experiments, the team aims to advance knowledge of earthquake causes and hazards.
Researchers have made significant findings on the state of stress in central and eastern North American seismic zones, providing insights into earthquake-generating stresses. Additionally, studies have mapped the depth domains of the Eastern Ghats Belt in India, offering clues to understanding ancient collisions.
The February issue of Lithosphere highlights the evolution of the northwestern Red Sea, with two main tectonic events contributing to its formation. The study also explores the Fish Lake Valley fault in eastern California and the incision of major rivers into the Tibetan Plateau's bedrock.
The study examines crustal melting during continental subduction, revealing evidence of igneous diapirism and its impact on mountain belts. Researchers also investigate the weight of the Andes affecting the continental crust and correlate the Mocha fracture zone with orogenic uplift.
A new study by an international team has used seafloor seismometers to image the Hawaiian mantle, revealing a high-temperature plume from the lower mantle. The findings suggest that the Hawaiian hot spot is the result of this upwelling plume, which tilts southeastward as it extends downward.
Seismic images of a mantle plume extending to depths of at least 1,500 kilometers reveal the roots of Hawaii's volcanic hotspot. The PLUME project provides high-resolution seismic images of the structure beneath the island of Hawaii.
Researchers have mapped the deep origins of the Hawaiian Hotspot using a large network of sea-floor seismometers. The study provides strong support for the existence of a mantle plume beneath Hawaii, with implications for the Earth's composition and evolution over time.
Karl E. Karlstrom received the GSA Distinguished Service Award for his exceptional leadership in publishing and editorial board service, while Bruce F. Molnia was awarded the GSA Public Service Award for enhancing public understanding of earth sciences through his photography and public outreach.
Researchers have developed a new model that explains the formation of banded iron formations, offering insights into the early ocean floor's composition and geochemical conditions. The study suggests that interactions between rocks, water, and air played a crucial role in creating these iconic formations.
Recent studies uncover new insights into the Miocene structural reorganization of the South Tibetan detachment, eastern Himalaya, and its implications for understanding continental collision. Additionally, researchers have developed a one-dimensional modeling approach to quantify dip and velocity of continental subduction from high-pre...
Researchers from Oregon State University create the most complete seismic image of the Earth's crust and upper mantle beneath the Himalayas. The study reveals unusual geologic features that help explain how the region has evolved and advances research on various fronts, including strain accumulation prior to large earthquakes.
A team of scientists has deployed a seismic network around Isla Isabela in the Galapagos to study Sierra Negra volcano. The new data will provide the first 3-D pictures of the volcanic plumbing system, helping to clarify its depth and extent.
Scientists are presenting research on coupled biogeochemical cycles, which study the interactions between Earth's biology, chemistry, and geology. The study highlights the importance of understanding these interconnected processes in addressing human impacts such as global warming and acid rain.
The article discusses four main questions: Subducted oceanic asthenosphere flow beneath the Juan de Fuca slab, Arkosic rocks from the San Andreas Fault Observatory at Depth (SAFOD) borehole, long-term strain records of the Parkfield Earthquake Prediction Experiment, and mechanisms responsible for map-view curvature over a range of scal...
Researchers at Rice University and Harvard University developed a new model to explain how noble gases are lost from the Earth's interior during mantle convection. The model suggests that both the upper and lower mantle are involved in convection, but they affect each other differently.
Researchers found a large cylindrical blob of cold material, known as a lithospheric drip, beneath the Great Basin in central Nevada. The finding provides new insights into fine-scale mantle convection processes and their connections to volcanism and mountain-building.
Recent research includes the documentation of Holocene rupture on major faults in Lake Tahoe Basin and evidence for a large paleolake in Western Desert, Egypt. A study on groundwater system in southern Colorado Plateau-Arizona Transition Zone also sheds light on seismic hazards in western Washington State.
Studies investigate the relationship between mantle cooling, crustal thickness, and sea-level rise. Researchers also explore the impact of tectonic stretching on fault formation and the behavior of Earth's plates.
Recent observations from the USArray transportable array and EarthScope instruments have shed new light on seismic wave propagation and the evolution of the Yellowstone hotspot. The analysis suggests a common mantle source for the region's unique topographic features, providing valuable insights into geological processes.
The first issue of Lithosphere features studies on Holocene surface ruptures in New Zealand, a fluid factory in solid Earth, and the erosion of the Wasatch Mountains. Researchers found evidence of five surface-rupturing earthquakes in New Zealand and proposed a new model for fluids in Earth's interior.
The Dead Sea's subsidence is attributed to a tectonic concurrence between the African and Arabian plates, resulting in a pull-apart basin. The basin's evolution is controlled by four parameters: brittle layer thickness, basin width, strike-slip displacement length, and upper mantle viscosity.
A research team led by Purdue Professor Eric Calais has captured the first recorded event of a 'dyking' process that breaks apart tectonic plates and weaks the Earth's lithosphere. This process, previously only theorized, can lead to the formation of oceans and continents.
The EUROCORES programme TOPO-EUROPE explores Europe's changing topography, combining solid Earth and climate scientists to understand past, present, and future changes. The project aims to refine sea level estimations and inform geological surveys on geothermal energy, seismic hazards, and slope instabilities.
Researchers found a special geochemical signature in Arctic volcanic rocks that resembles the one found only in the southern hemisphere. The discovery suggests that processes at work in the Indian Ocean might have an analog in the northern hemisphere, and sheds light on the origin of the Dupal anomaly.
Researchers isolated the signal of ocean global warming by analyzing historical temperature records. Volcanic loading in Hawaii triggered earthquakes with divergent mechanisms. Climate scientists found anticorrelated precipitation patterns between China and Brazil, suggesting oceanic circulation triggers abrupt climate events.
Researchers used satellite data to monitor inflation in the Lastarria-Cordon del Azufre volcanic complex, detecting a long wavelength signal indicating possible magmatic activity. A short wavelength signal was also found, likely linked to hydrothermal fluid circulation.
UC Berkeley scientists discovered that Mars' shoreline variations can be explained by the movement of its spin axis, and thus its poles. The team calculated that an initial shift of 50 degrees from today's pole would disrupt the Arabia shoreline.
A team of Canadian and U.S. researchers have found evidence that ragged features on Mars' surface were once shorelines of massive ancient oceans. The study suggests that a shift in Mars' spin axis within the past 2-3 billion years deformed these shorelines.
Geologists use seismic waves to locate missing rock under Tibet, clarifying how continents behave when they collide. The research helps solve a long-standing mystery and provides key evidence for understanding the full dynamics of continental collision.
Geologist Robert D. Hatcher Jr has made significant contributions to the field of geology, including applying plate tectonics to the southern Appalachians and pioneering new seismic exploration techniques. He is recognized for his work through the prestigious Penrose Medal from the Geological Society of America.
Dr. George Papanicolaou was chosen for his significant contributions to mathematics and its applications, including imaging in random media and financial mathematics.
A team of seismologists detected a slab of sunken ocean floor at the Earth's core-mantle boundary, shedding light on mechanisms that give rise to volcanoes and earthquakes. The discovery suggests whole mantle circulation and provides new insights into the movement of tectonic plates.
Scientists have discovered a subducted slab of oceanic lithosphere at the base of the Earth's mantle, providing direct evidence for its presence. The finding reveals new insights into the processes driving tectonic plate movement, suggesting that ancient seafloor can sink to the bottom of the mantle.
Researchers from UC Berkeley found no signature of life in Earth's topography, contrary to previous assumptions. Instead, they suggest that life's influence is more subtle, shaping landforms like rounded hills and meandering rivers, but not creating unique features.
A graduate student's seismic study has found a sharp dividing line between the lithosphere and asthenosphere, contradicting the idea that the transition is gradual. The research suggests water or partly molten rock must be present in the asthenosphere to cause such an abrupt change.
Dr Christine Thomas has discovered a previously undetected seismic layer near the Earth's core-mantle boundary, allowing researchers to measure internal temperatures and study whole mantle convection. The new layer enables scientists to examine the fate of subducted lithosphere and hot material rising from the core-mantle boundary.
Researchers propose alternative explanation for fault formation at mid-ocean ridges, citing role of magma and rotation of faults. The study suggests that large offset 'oceanic core complex' faults may form due to bending of lithosphere, contradicting the previous standard model.
Scientists study hydrogen's effect on upper mantle melting, revealing new data for improving earthquake hazard estimates. A computing technique analyzes seismic data to monitor active volcanoes worldwide. Comets may help track solar ejections and heliospheric conditions.
The combined database will help researchers determine the origin of magnetic signals in Earth's crust. With over 36,000 rock samples, it will improve our understanding of Earth's structure and development.
Researchers analyze Martian flood channels, estimate Mercury's crust depth and simulate earthquake dynamics. New data also reveals details on sprites and interstellar hydrogen shadows.
A team of UC Berkeley scientists resolves a long-standing puzzle in earth science by clarifying the depth of the continental lithosphere. By re-examining earthquake-generated seismic waves, they determine that the boundary between the lithosphere and asthenosphere lies at 200-250 kilometers.
Researchers found that small-magnitude earthquakes and micro-cracking in a region called the process zone precede propagation, followed by nucleation of the rift axis and upwelling of magma. This new understanding can be applied to more complex rift settings in oceans and continents.
Studies reveal steady rate of oceanic lithosphere creation over past 180 million years, contrasting with decreasing estimates. Researchers analyze structural investigation of San Juan thrust system and kinematic history of central Andean fold-thrust belt to build high plateaus.
Researchers are studying the chemical signatures of lavas from the Rift Valley in Turkana to understand the evolution of mantle plumes and how continents split apart. The study suggests that a mantle plume was present in the area 35 million years ago, contributing to the formation of the African Rift Valley.
Scientists investigated subducting lithosphere and deep earthquakes near Fiji, finding a group of deep earthquakes off to the side that cannot be connected to the actively subducting lithosphere. The researchers suggest that similar slabs may exist elsewhere, preserving a significant primordial component of the mantle.
Researchers created a wax experiment that replicates ocean floor spreading, allowing them to study millions of years of geological time. The experiments revealed the formation of microplates, tiny chunks of solid wax that roll up and rotate in a spiral shape, mirroring the Earth's natural phenomenon.
Researchers have identified a 150-million-year-old piece of Earth's crust submerged in the mantle beneath Siberia's Lake Baikal. The study provides evidence that subducted slabs eventually sink to the Earth's core, shedding light on the planet's internal dynamics.
Researchers Norman H. Sleep and Cindy J. Ebinger find that a single giant plume of magma rose from Earth's mantle 45 million years ago, shaping Africa's striking geological features such as Mount Kilimanjaro and the Ethiopian plateau.
A new model of Venus suggests that crustal plateaus and volcanic rises were formed by a mechanism similar to hot spot plumes, a process still active on Earth. The thickening of the Venusian lithosphere approximately one billion years ago largely shut down the creation of crustal plateaus.
A revised ocean depth model developed by Northwestern University geologists significantly better fits observed data, correcting inconsistencies in existing models. By adjusting the assumed thickness of the lithosphere to 95 kilometers, the new model accurately predicts ocean depths surrounding the Hawaiian Islands.