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Lava field

A lava field, also referred to as a lava flow field, is an extensive area of solidified basaltic lava flows produced by one or more effusive volcanic eruptions, where molten rock spreads across the landscape to form broad, relatively flat terrains.^[1] These fields typically result from low-viscosity basaltic magma, which allows flows to travel distances of tens of kilometers, creating dramatic, dark rock surfaces that dominate volcanic landscapes.^[1] Unlike explosive volcanic deposits, lava fields represent the accumulation of fluid lava that cools and solidifies on the Earth's surface without fragmenting into ash or pyroclasts.^[2] Lava fields form primarily during non-explosive eruptions from shield volcanoes, fissure vents, or monogenetic cones, where high eruption rates and gentle slopes enable the lava to advance as broad sheets, channeled streams, or through subsurface tubes.^[1] The basaltic composition, with low silica content (around 45-52%),^[3] imparts high fluidity to the lava, facilitating flow speeds up to 30 km per hour in tubes and covering areas from a few square kilometers to over 1,000 km² in larger fields.^[1] Topography, eruption duration, and cooling rates influence the field's morphology, with some fields developing complex networks of tubes and caves that preserve heat and extend flow lengths.^[1] The surface textures of lava fields vary distinctly based on flow dynamics: pahoehoe flows produce smooth, ropy, or billowy surfaces from slower, cooler movement, while ʻaʻā flows create rough, jagged, clinkery terrains from faster, more turbulent advance.^[1] These features not only record the eruption's conditions but also affect erosion, vegetation, and human use of the land.^[4] Many lava fields are polygenetic, built from multiple eruptions over thousands to millions of years, as seen in the Craters of the Moon lava field in Idaho, which spans about 1,600 km² with over 60 flows from various vents dating from about 15,000 to 2,000 years ago.^[5] Prominent examples illustrate the global distribution and diversity of lava fields, often associated with hotspots or rift zones. The Hell's Half Acre lava field in Wyoming covers 400 km² and exemplifies young basaltic activity in the Snake River Plain, with flows as recent as 5,200 years old.^[6] In New Mexico, the Zuni-Bandera volcanic field includes extensive ʻaʻā and pahoehoe flows from over 100 cinder cones, forming rugged terrains preserved in El Malpais National Monument.^[7] Such fields contribute to geological understanding of mantle plumes and plate tectonics, while hosting specialized ecosystems adapted to nutrient-poor, rocky substrates.^[5]

Definition and Formation

Definition and Characteristics

A lava field is defined as a large, mostly flat expanse of solidified basaltic lava flows, typically resulting from one or more effusive eruptions, covering areas ranging from a few square kilometers to hundreds of square kilometers. Lava fields can form from a single large eruption, such as the 1783-1784 Laki event that produced the Eldhraun field in Iceland, which spans approximately 565 square kilometers, illustrating the scale possible from major effusive events.^[8]^[9]^[10] These features form broad, low-relief landscapes where the lava has spread extensively due to its fluid nature during emplacement. Key characteristics of lava fields include their predominant basaltic composition, which contains low silica content (typically 45-52%), enabling low viscosity and allowing the molten material to flow rapidly over great distances before solidifying.^[3] This results in flat or gently undulating topography with minimal elevation changes, in stark contrast to the steep profiles of volcanic cones or domes. Lava fields commonly develop in extensional tectonic settings, such as rift zones along divergent plate boundaries or intraplate hotspots, where magma ascends easily to the surface.^[11]^[12] Surfaces may exhibit textures like smooth pahoehoe or rough aa, reflecting variations in flow dynamics.^[1] Lava fields differ from volcanic fields, which encompass clusters of multiple vents, cinder cones, and other edifices across a broader region prone to localized eruptions, whereas lava fields emphasize the expansive, overlapping sheets of flows without prominent central structures.^[13] They also contrast with individual lava flows, which represent singular eruptive episodes rather than the buildup from one or more events that defines a field, where successive flow lobes or layers can bury earlier deposits, creating a cohesive, low-gradient terrain.^[14] The earliest documented observations of lava fields date to 18th-century explorations in Iceland, where the 1783–1784 Laki eruption produced vast flows that were meticulously recorded by local priest Jón Steingrímsson, influencing modern geological terminology for such features.^[15]

Formation Processes

Lava fields primarily form through effusive eruptions of basaltic magma from fissure vents or low-relief shield volcanoes, where non-explosive activity allows molten lava to spread laterally across extensive areas rather than building up steeply.^[1] These eruptions occur when low-viscosity basaltic lava, characterized by its fluid nature due to low silica content, emerges at the surface and flows outward, covering landscapes over distances of tens to hundreds of kilometers.^[1] The formation process begins with magma ascent from the mantle, driven by partial melting at hotspots or along rift zones, where upwelling heat reduces the melting point of peridotite.^[16] As magma rises through the crust, it undergoes degassing near the surface, releasing volatiles like water and carbon dioxide.^[17] Upon eruption, the lava advances at typical rates of 1 to 10 meters per second, influenced by slope and channel development, before cooling begins.^[1] Initial crust formation occurs within hours to days via radiative and convective cooling at the surface, while full solidification of thicker flows (4-5 meters) can take over 130 days to reach temperatures around 200°C, with complete cooling to ambient levels extending into years due to insulation by the outer crust and conductive heat loss at the base.^[18] Tectonic settings play a crucial role, with most lava fields associated with divergent plate boundaries such as mid-ocean ridges, where plate separation facilitates magma upwelling, or intraplate hotspots like those beneath Iceland or Hawaii, generating persistent volcanic activity.^[16] Underlying topography influences flow paths by channeling lava into valleys or depressions, enhancing lateral spread and thickness buildup in low-relief areas.^[19] Over time, lava fields develop through repeated eruptions spanning thousands to millions of years, with successive flows stacking to form layers 10 to 50 meters thick, as seen in continental flood basalt provinces.^[20]

Classification and Types

By Lava Composition and Viscosity

Lava fields are primarily classified by the chemical composition of their constituent lavas, which directly influences viscosity and thus the scale, shape, and extent of the resulting fields.^[21] Basaltic lava fields dominate globally due to their low silica content, typically 45-52 wt% SiO₂, which imparts high fluidity and enables the formation of vast, expansive fields covering hundreds of square kilometers.^[22] In contrast, andesitic and rhyolitic lava fields are rarer, as their higher silica contents—57-63 wt% SiO₂ for andesite and over 69 wt% SiO₂ for rhyolite—result in greater polymerization of the melt, leading to more viscous flows that produce shorter, thicker, and more confined fields.^[22]^[21] Viscosity, a key rheological property, governs how far and how thinly lava spreads to form fields, with low-viscosity basaltic lavas (typically 10-1000 Pa·s at eruption temperatures around 1000-1200°C) allowing rapid, far-reaching flows that create broad, flat expanses.^[23] Higher-viscosity andesitic lavas (around 10³-10⁴ Pa·s) and especially rhyolitic lavas (10⁴-10⁶ Pa·s) resist flow, resulting in stubby, dome-like or blocky fields with limited lateral extent, often less than a few kilometers across.^[21]^[24] This viscosity-driven variation affects field morphology, as basaltic flows cool slowly over distance to form coherent sheets, while siliceous ones fracture and pile up due to internal stresses.^[23] Within basaltic fields, subtypes like tholeiitic and alkalic basalts further modulate flow behavior; tholeiitic basalts, common in hotspot settings such as Hawaii, are iron-rich and subalkaline, forming larger fields, while alkali-enriched alkalic basalts are found in ocean island margins.^[25] Intermediate compositions, such as basaltic andesites, occur rarely in transitional tectonic settings like continental rifts, where they produce moderately extensive fields blending basaltic fluidity with andesitic resistance.^[26] Examples include the predominantly basaltic Columbia River Basalts in the U.S., expansive tholeiitic fields covering over 160,000 km², versus rarer rhyolitic fields in Yellowstone National Park, where viscous flows form confined plateaus like the Upper Basin.^[22] Andesitic examples are seen in the Mount Edgecumbe Volcanic Field in Alaska, where intermediate lavas create rugged, limited fields amid more dominant basalts.^[27] Geochemical analysis is essential for classifying lava field compositions, with techniques like X-ray fluorescence (XRF) spectroscopy widely used to quantify major elements such as SiO₂ from rock samples, providing precise viscosity proxies without destructive sampling.^[28] XRF's non-invasive nature allows rapid assessment of field-wide variations, confirming, for instance, the low-silica dominance in basaltic provinces.^[29]

By Morphological Features

Lava fields are classified morphologically based on the surface textures, landforms, and structural complexities resulting from the flow dynamics during eruption, which reflect variations in flow velocity, viscosity, and environmental interactions. These features provide insights into the eruptive behavior and can be observed directly on the surface without requiring subsurface analysis. Predominantly basaltic lava fields exhibit these morphologies due to their low viscosity, enabling diverse flow patterns. Texture-based subtypes form the primary morphological distinction in lava fields. Pahoehoe-dominated fields feature smooth, ropy, or billowy surfaces formed by slow-moving, laminar flows that develop through folding and shearing of the plastic crust, often covering extensive areas with undulating lobes up to several meters wide. In contrast, aa-dominated fields display rough, jagged, clinkery surfaces with spinose fragments and rubble, arising from faster, more turbulent flows where the crust breaks repeatedly, typically advancing at rates exceeding 10-30 meters per hour. Transitional or block lava fields combine elements of both, with slabby or blocky textures emerging from flows that accelerate mid-eruption, producing entrained blocks up to 1-2 meters in size embedded in a fragmented matrix. Landform variations further differentiate lava fields by their topographic expression. Shield-like fields develop gentle slopes (typically 1-5 degrees) from prolonged, low-effusion-rate eruptions that build broad, convex-up profiles resembling volcanic shields, with flows radiating outward over distances of kilometers. Plateau fields, conversely, form on relatively flat terrain through high-volume effusions that spread laterally without significant elevation gain, creating expansive, nearly level expanses bounded by steep flow fronts. Tube-fed fields are characterized by channeled flows within insulated lava tubes, resulting in surface features like linear ridges, collapse pits (skylights up to 10-20 meters wide), and drained channels that indicate subsurface transport over long distances. The scale and complexity of lava fields vary with eruption duration and flow interactions, influencing morphological development. Simple fields consist of single or few overlapping flows with minimal structural features, often from short-lived eruptions lasting days to weeks, covering areas of 1-10 square kilometers. Complex fields arise from prolonged eruptions (months to years), where repeated flows create levees—raised embankments 2-10 meters high formed by solidified flow margins—and pressure ridges, which are compressional folds up to 5-15 meters high resulting from flow inflation and stagnation. Longer eruption durations promote greater complexity by allowing thermal insulation and repeated inundation, enhancing feature diversity. Morphological identification in the field relies on observable criteria such as surface texture, flow front characteristics, and structural elements. For instance, aa flows are distinguished by their steep, rubble-strewn fronts 1-5 meters high, contrasting with the more gradual, intact lobes of pahoehoe (often less than 1 meter high). Field criteria also include the presence of vesicles, cooling cracks, and flow direction indicators like aligned ropes or blocks, enabling rapid classification during surveys.

Physical Morphology and Structure

Surface Morphology

The surface morphology of lava fields is dominated by primary features that emerge during the emplacement and cooling of basaltic flows, including flow lobes, tumuli, and squeeze-ups. Flow lobes represent the bulbous, advancing fronts of pahoehoe lava, formed as molten material extends incrementally with a thin, cooling crust that insulates the interior. Tumuli, or inflation blisters, appear as low, dome-like mounds typically less than 10 m high, resulting from internal pressure buildup that buckles the solidified crust over confined lava pathways. Squeeze-ups occur as viscous lava extrudes through cracks in the crust, forming bulbous or wedge-shaped protrusions up to 0.7 m in size, often enriched in phenocrysts. During cooling, a glassy rind develops on the surface within hours, trapping gas bubbles that create vesicles—small, rounded voids—while the underlying crust thickens to protect the still-molten core.^[4]^[30]^[4] Texture variations on lava field surfaces reflect the rheological behavior of the flows, with pahoehoe exhibiting smooth, ropy, or billowy forms and 'a'ā displaying rough, jagged profiles. In pahoehoe, shelves form as flat, overhanging extensions of the crust along flow margins, while toes develop as small, bulbous extensions at the advancing edge, created by low-velocity extrusion of fluid lava that skins over rapidly. 'A'ā textures consist of clinkers—sharp, spinose blocks—and rubble, generated when faster-moving, viscous lava fractures its cooling surface into loose, angular fragments that accumulate as the flow advances. Over centuries, weathering through oxidation alters these textures, producing red-black patinas as iron minerals in the basalt convert to hematite, dulling the initial shiny black or iridescent rind and creating a mottled appearance.^[31]^[4]^[32] Topographically, lava fields exhibit gentle undulations with overall slopes typically less than 5°, fostering broad, low-relief expanses that extend for kilometers. These subtle elevations and depressions arise from the irregular advance of flow lobes and inflation features, creating a hummocky terrain. Drainage patterns are often impeded by the impermeable flows, which dam pre-existing valleys and force water to divert around margins, resulting in irregular networks that serve as indicators of underlying volcanic geology. On older surfaces, vegetation colonization follows primary succession patterns, beginning with pioneer species like lichens and ferns in moisture pockets, progressing to shrubs and trees over decades to centuries, with denser cover on windward, wetter slopes compared to arid exposures.^[33]^[34]^[35] Evolutionary changes in surface morphology transition from initial post-eruption instability, where fragile, thin crusts collapse under thermal stress or minor loading, to long-term stability as the flows solidify fully. This instability phase, lasting days to weeks, involves spalling and minor slumps of the glassy rind, exposing incandescent interiors. Over time, in arid climates, erosion proceeds at low rates of 0.001–0.005 mm/year, primarily through chemical weathering and occasional physical breakdown, preserving the overall form while gradually rounding edges and deepening fissures.^[4]^[36]

Internal Structure and Layering

Lava fields exhibit distinct layering patterns resulting from sequential emplacement and cooling of multiple flow units. Individual flows often display superimposed layers with chilled margins at their bases and tops, formed by rapid cooling against the underlying substrate or atmosphere. These margins are typically glassy or finely crystalline, transitioning inward to coarser interiors. Rubbly bases, characterized by fragmented and brecciated material, arise from shear zones where the flow base interacts with the ground, leading to autobrecciation during movement. Thickness variations are common, with flows generally thinner at their lateral edges due to faster cooling and spreading, and thicker centrally where insulation preserves heat longer, allowing greater accumulation.^[37] Internal features within these layers include systematic vesicle distributions, where dense, vesicle-poor bases grade upward into more vesicular zones and spongy, highly porous tops. This pattern reflects degassing dynamics, with bubbles initially trapped at the flow base and migrating upward as the lava cools and crystallizes. Autobrecciation can occur in flow interiors, particularly in more viscous lavas, producing internal breccias from tensile stresses during flow. Additionally, crystal segregation during emplacement leads to zones enriched in phenocrysts, such as olivine or plagioclase, separated from the melt by gravitational settling or flow-induced sorting.^[38]^[39]^[40] Geophysical methods reveal these internal structures through contrasts in physical properties. Seismic velocity profiles show cyclic patterns corresponding to individual flows, with lower velocities in vesicular upper crusts and higher velocities in dense cores, highlighting density contrasts from porosity variations. Magnetic anomalies arise from cooling-induced alignments of magnetic minerals like magnetite, producing dipolar patterns that delineate flow boundaries and thicknesses, especially in basaltic fields.^[41]^[42]^[43] Specific structures form through cooling and degassing processes. Pipe vesicles develop in basal zones as dissolved volatiles exsolve into bubbles that rise vertically through the semi-molten lava, creating elongated pipes up to several meters long. In rare cases, thermal contraction during slow cooling produces columnar jointing, where perpendicular fractures form hexagonal prisms in the flow interior, accommodating shrinkage stresses. These features, while internal, may subtly influence overlying surface textures through differential weathering.^[38]^[44]^[45]

Scientific Study and Applications

Mapping and Remote Sensing Techniques

Ground-based mapping of lava fields involves detailed field surveys to delineate flow boundaries and document stratigraphic features. Scientists employ GPS-enabled devices to precisely record the edges of lava flows, often supplemented by drone-based photogrammetry for high-resolution aerial imagery that captures flow extents in challenging terrains. For instance, during eruptions in Hawaii, the U.S. Geological Survey (USGS) uses handheld GPS units and unmanned aerial vehicles (UAVs) to map active flow fronts and channels in real-time, enabling accurate boundary delineation with positional errors typically under 1 meter.^[46] Stratigraphic logging of outcrops further reveals layering and compositional variations, achieved through on-site sampling and direct observation to construct cross-sectional profiles of the lava field. Remote sensing techniques have revolutionized lava field documentation by providing broad-scale, non-invasive data. Satellite imagery from platforms like Landsat utilizes thermal infrared bands to detect heat signatures and estimate flow ages through changes in vegetation cover, as older flows show increased near-infrared reflectance due to revegetation. LiDAR (Light Detection and Ranging) systems generate 3D topographic models with resolutions better than 1 meter, facilitating precise mapping of flow morphology even under vegetation; for example, airborne LiDAR surveys of Kīlauea volcano have quantified volume changes in active flows with centimeter-level vertical accuracy.^[47] Hyperspectral imaging enhances composition mapping by capturing narrow spectral bands that distinguish mineralogies, such as distinguishing basaltic from andesitic lavas in fields like Krafla, Iceland, through unique reflectance signatures in the visible to shortwave infrared range. Mapping approaches have evolved significantly from historical methods to modern computational techniques. In the 19th century, lava fields were documented via manual sketches and rudimentary surveys, as seen in early geological maps of Mount Etna by Waltershausen (1845–1859), which relied on field observations without geospatial precision.^[48] Post-2010s advancements incorporate AI-assisted analysis, including machine learning classifiers applied to multispectral data for automated flow detection; supervised random forest algorithms, for instance, achieve over 90% accuracy in delineating recent lava extents on Mount Etna using Sentinel-2 imagery.^[49] Recent studies as of 2023 continue to refine these techniques for near-real-time monitoring. These modern methods outperform historical techniques by integrating temporal data series for dynamic monitoring. Data integration in geographic information systems (GIS) unifies these datasets into comprehensive lava field databases. Layers from ground surveys, LiDAR DEMs, and satellite imagery are overlaid with eruption chronologies in tools like QGIS, enabling spatial analysis of flow evolution; the open-source Q-LAVHA plugin, for example, facilitates probabilistic inundation modeling within QGIS environments for hazard-prone regions.^[50] This approach supports global databases, such as those maintained by the USGS for Hawaiian volcanoes, where integrated maps correlate flow ages with morphological features like pahoehoe and aa surfaces.

Hazard Assessment and Prediction

Hazard assessment for lava fields primarily evaluates risks associated with active or potential flows, focusing on direct threats to human life, infrastructure, and ecosystems. Key hazards include flow inundation, where advancing lava engulfs and destroys structures, roads, and landscapes in its path. Hot lava flows can also ignite vegetation and buildings, leading to widespread wildfires that exacerbate damage beyond the flow itself. Additionally, fresh lava surfaces create barren, infertile substrates that hinder vegetation regrowth and agricultural use for decades, though long-term soil enrichment may occur through weathering. Probability models for these hazards often rely on recurrence intervals derived from geological records of past eruptions in basaltic fields. For monogenetic basaltic volcanic fields, repose intervals typically range from hundreds to several thousand years (e.g., 100-3000 years), informing long-term risk zoning.^[51] These models integrate historical data to estimate eruption likelihood, such as one event every few centuries in fields like Craters of the Moon, where intervals approximate 2000 years but vary locally.^[51] Prediction methods combine geophysical monitoring and numerical simulations to forecast eruption onset and flow progression. Eruption forecasting employs seismic swarms—clusters of earthquakes signaling magma movement—and ground deformation detected via Interferometric Synthetic Aperture Radar (InSAR), which measures surface uplift or subsidence with millimeter precision to anticipate vent locations. Flow simulation software, such as the DOWNFLOW probabilistic model, predicts advance rates and paths by incorporating topography, rheology, and effusion rates, enabling real-time hazard mapping during outbreaks.^[52] Mitigation strategies emphasize proactive planning to minimize impacts. Zoning laws restrict development in high-risk zones around established lava fields, designating areas prone to inundation as protected or limited-use. Evacuation planning accounts for initial flow velocities, which can reach up to 10 km/h on steep slopes for basaltic lavas, though channelized flows may accelerate to 50 km/h briefly, necessitating rapid alerts and predefined routes to ensure safe egress.^[1] Global databases like the Smithsonian Institution's Global Volcanism Program provide trend analysis of eruption histories and hazards, supporting updated probabilistic models for fields worldwide.

Geological Significance and Examples

Role in Volcanic Landscapes

Lava fields play a pivotal role in the geological evolution of volcanic landscapes by contributing to crustal thickening, particularly in rift zones where repeated effusions of basaltic lava fill topographic lows and accumulate in layers averaging 250 meters thick, thereby reducing basin rugosity and adding substantial volume to the lithosphere.^[53] These accumulations modify rift topography, creating structural highs that influence sediment routing and enhance overall crustal stability during post-rift stages.^[53] Furthermore, lava fields serve as critical archives for paleovolcanology, preserving detailed records of ancient eruptive processes through their landforms, such as scoria cones and varied lava morphologies ranging from 'a'ā to pāhoehoe, which document styles from effusive to explosive activity driven by magmatic volatiles.^[54] The internal structures of these flows, including vesicular and massive layers, remain largely intact in ancient terrains, allowing reconstruction of magma ascent paths and eruption dynamics over Quaternary timescales.^[55] In addition, established lava fields can influence subsequent magmatism by altering local stress regimes and thermal profiles, facilitating shear-driven melt segregation in intraplate settings and promoting recurrent basaltic activity along tectonic lineaments.^[54] Ecologically, lava fields initiate primary succession on barren substrates, where pioneer species such as lichens and algae first colonize the surface, breaking down rock through weathering and nitrogen fixation to enable soil development.^[35] Over centuries, this progresses to mosses, ferns, and vascular plants, eventually supporting shrublands and forests as organic matter accumulates, with full canopy closure occurring in less than 150 years in wet regions on basaltic substrates, though longer in drier areas.^[35] The weathering of lava produces fertile andisols, characterized by high organic content and water retention, which foster nutrient-rich soils capable of sustaining productive ecosystems after prolonged exposure.^[56] Fragmented lava fields, with their mosaic of flows and cracks, create heterogeneous habitats that enhance biodiversity, serving as refugia for endemic species and promoting ecological connectivity in volcanic regions.^[57] Lava fields interact with global climate systems through contrasting processes of gas release and long-term sequestration. During formation, large effusive events emit substantial CO₂, with individual flood basalt episodes releasing millions of tons into the atmosphere, contributing to transient greenhouse warming as seen in historical large igneous provinces.^[58] Conversely, post-emplacement basaltic weathering sequesters CO₂ via mineral carbonation, accounting for 30–35% of natural global drawdown, as rainwater reacts with silicates to form stable carbonates over millennia.^[59] From a human perspective, lava fields provide essential resources, including crushed basalt aggregates for construction, valued for their durability and derived from ancient volcanic quarries that yield high-quality material for infrastructure.^[60] Culturally, these landscapes hold profound significance for indigenous communities, embodying spiritual entities like the Hawaiian goddess Pele, where eruptions are honored through ceremonies, prayers, and offerings that reinforce ancestral ties to the land.^[61] Recent 2020s research highlights their potential in enhanced weathering for carbon capture, where finely crushed basaltic rocks from lava fields are applied to agricultural soils to accelerate CO₂ mineralization, improving fertility while removing up to several tons of carbon per hectare annually in tropical settings.^[62]

Notable Lava Fields Worldwide

One of the most prominent examples of a historical lava field is the Laki lava field in Iceland, formed during the 1783–1784 eruption along a 27-km-long fissure in the Eastern Volcanic Zone. This event produced approximately 14–15 km³ of basaltic lava, covering 565 km² primarily with pāhoehoe flows, including slabby and rubbly variants that exemplify insulated transport in low-viscosity basaltic eruptions.^[63] The Columbia River Basalt Group in the northwestern United States represents a classic flood basalt province, erupted during the Miocene epoch from about 17.5 to 6 million years ago, covering over 210,000 km² across Oregon, Washington, and Idaho. Composed mainly of tholeiitic basalt flows, it exemplifies large-scale, repetitive effusive volcanism with individual flows reaching thicknesses of 10–50 m and volumes exceeding 1,000 km³ in major formations like the Grande Ronde Basalt.^[64]^[65]^[66] In diverse environmental contexts, the Toomba lava field in northeastern Australia highlights Holocene volcanism adapted to semi-arid conditions. Erupted around 13,000 years ago from a monogenetic vent in the Nulla Volcanic Province, it produced a remarkably long, tube-fed pāhoehoe flow extending 120 km eastward, with rise ridges indicating sustained distal flow in a low-gradient, dry landscape.^[67]^[68]^[69] Remnants of the Deccan Traps in west-central India provide insight into ancient, extinction-linked lava fields from the late Cretaceous period, approximately 66 million years ago. This continental flood basalt province originally covered an estimated 1,000,000–1,500,000 km² with stacked flows up to 3 km thick, now eroded but exposing about 500,000 km²; its massive volatile emissions, including sulfur and CO₂, are temporally correlated with the Cretaceous-Paleogene mass extinction event.^[70]^[71]^[72] The San Francisco Volcanic Field in northern Arizona, USA, illustrates monogenetic vent-dominated lava fields spanning the Pleistocene to Holocene. Encompassing over 600 basaltic vents within a 5,000 km² area, it features short-lived cinder cones and associated 'a'ā and pāhoehoe flows, such as those from Sunset Crater's 1085 CE eruption, demonstrating clustered, low-volume effusions in a continental rift setting.^[73]^[74]^[75] Australia's Newer Volcanics Province in southeastern Victoria and South Australia exemplifies an active, intraplate basaltic field spanning the last 4.5 million years. Covering about 15,000 km² with over 400 monogenetic vents and extensive flows, it poses ongoing eruption threats due to its youth and proximity to urban areas like Melbourne, with Holocene activity including the ~5,000-year-old Mount Schank scoria cone and older features like Mt. Eccles (~37,000 years ago).^[76]^[77]^[78] A modern analog is the series of eruptions at Fagradalsfjall and nearby Sundhnúkur on Iceland's Reykjanes Peninsula, beginning in 2021. The initial subglacial-to-surface event from March to September 2021 produced about 0.15 km³ of basaltic lava, covering 4.85 km² with diverse pāhoehoe and 'a'ā flows. This was the first on the peninsula in over 800 years, offering insights into rift-zone dynamics and serving as a smaller-scale comparison to historical fields like Laki, with effusion rates peaking at 20 m³/s. Subsequent eruptions occurred in 2022–2025, with cumulative lava volume exceeding 0.3 km³ and area over 6 km² as of November 2025, highlighting ongoing reactivation of the rift.^[79]^[80]^[81]

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[PDF] Ambient effects on basalt and rhyolite lavas under Venusian ...
The viscosity of basaltic melt, with few bridging oxygens, typically ranges from hundreds to thousands of Pa s whereas rhyolitic melt, which is more polymerized ...
[25]
[PDF] Chapter 3 Growth and Degradation of Hawaiian Volcanoes
Late-shield strata extend the silica range as alkali basalt and even hawaiite lava flows are sparsely interlayered with tholeiite at some volcanoes. Rare are ...
[26]
FAQ Volcanoes: Naming Volcanic Rocks
Volcanic rocks are named based on silica, iron, magnesium, and alkalinity. Examples include rhyolite, basalt, andesite, dacite, latite, and trachyte.
[27]
[PDF] The Mount Edgecumbe Volcanic Field - Alaska Volcano Observatory
Andesitic lava flows erupted by Mount Edgecumbe, heavily covered by air fall ash and pumice and by pyroclastic-flow deposits erupted by. Crater Ridge crater.
[28]
[PDF] 35. xrf analyses of volcanic rocks from leg 152 by laboratories
The lavas were cored at Sites 915, 917, and 918 and were sampled for geochemical analysis, mainly X-ray fluorescence spectrometry (XRF), in both Edinburgh and ...
[29]
[PDF] GEOCHEMISTRY OF THE INYO VOLCANIC CHAIN, AND ...
X-ray fluorescence (XRF) has been used for over 50 years to determine the elemental composition of many types of materials including igneous rocks.
[30]
Morphology and development of pahoehoe flow-lobe tumuli and ...
These tumuli are characterized by low, dome-like mounds, lava-inflation clefts, and squeeze ups. Flow-lobe tumuli are of various shapes and sizes, which are ...
[31]
What are the different types of basaltic lava flows and how do they ...
A'a is characterized by a rough, jagged, spinose, and generally clinkery surface. Aa lava flows tend to be relatively thick compared to pahoehoe flows. During ...
[32]
Volcano Watch — Lava rocks come in many colors - USGS.gov
Eventually, with exposure to the elements, the color of the rock turns to black. As older lava flows weather, the minerals in the rocks oxidize and often turn ...Missing: patina | Show results with:patina
[33]
Can Lava Flow Like Water? Assessing Applications of Critical Flow ...
Aug 25, 2022 · This consistency indicates that in Hawaiʻi, where flow slopes are typically ∼0.01 to 0.1 m/m (∼0.5°–6°), velocities sufficient to form ...Missing: degrees | Show results with:degrees<|separator|>
[34]
Lava Flow - an overview | ScienceDirect Topics
The length of an eruption is a factor frequently controlling the width of the lava flow field. Longer lasting eruptions are associated with complex lava flow ...
[35]
Volcano Watch — From lava flow to forest: Primary succession
The process of colonization of such flows by plants and animals is called primary succession, and it is also found on other newly formed surfaces.
[36]
Erosion after an extreme storm event in an arid fluvial system of the ...
May 11, 2020 · The calculated mean erosion rates of 0.03–0.08 mm yr−1 during the last 6–10 Myr do not reach the total degradation of the Miocene surfaces ...Missing: lava crust collapse
[37]
[PDF] Report (pdf) - USGS Publications Warehouse
lava flow) were mapped separately and will be described in subsequent ... (<_ 10 m) near its edges and thicker in the center. North of. Morgan Mountain ...
[38]
Reevaluation of vesicle distributions in basaltic lava flows
We demonstrate that fundamental features of the flow structure—a thick upper vesicular crust that diminishes downward in overall vesicularity, a dense flow ...
[39]
[PDF] 37. origin of segregation vesicles in volcanic rocks from the lau ...
I present here the results of a detailed geochemical study of these segregations and of their host lavas and suggest a mechanism for their development.
[40]
[PDF] Cooling history and emplacement dynamics within rubbly lava flows ...
Lavas cool faster at the upper surface than the base of the flow due to radiative cooling and the effects of wind and rainfall. Thus, the final depth of ...
[41]
[PDF] 3. the effect of cracks on the seismic velocities of basalt from site 990 ...
Cyclic velocity patterns are evident throughout the profile. Each full cycle (i.e., low velocity–high velocity–low veloc- ity) corresponds to a single lava flow ...
[42]
Compressional-wave seismic velocity, bulk density, and their ...
Jul 19, 2023 · Compressional-wave seismic velocity (velocity) and bulk density (density) data were compiled from published sources for rock suites and earth materials
[43]
The Magnetic Thickness of a Recent Submarine Lava Flow
Mar 1, 1997 · The new lava flow produces an extremely strong near-bottom magnetic field anomaly of approximately 15,000 nano Teslas (units of magnetic field ...
[44]
Columnar Jointing | Volcano World - Oregon State University
Columnar jointing forms in lava flows, sills, dikes, ignimbrites (ashflow tuffs), and shallow intrusions of all compositions.Missing: thermal contraction
[45]
Disclosing the temperature of columnar jointing in lavas - PMC
Apr 12, 2018 · Columnar joints form by cracking during cooling-induced contraction of lava, allowing hydrothermal fluid circulation.
[46]
The interactions of volcanism and clastic sedimentation in rift basins ...
Dec 23, 2021 · Volcanism in the late syn-rift and early post-rift occurs as thick lava flow and pyroclastic facies that infill rift topographic lows and ...
[47]
Quaternary basaltic volcanic fields of the American Southwest
Nov 2, 2021 · Volcanic fields typically have lifespans on the order of a few million years and can contain hundreds of individual volcanoes down to a single ...
[48]
Volcano Geology Applications to Ancient Volcanism-Influenced ...
This chapter discusses how to apply the most significant aspects and concepts of modern volcanology to the study the ancient volcanic terrains.3. Volcanic Deposits · 3.1 Lithological... · 3.1. 1 Lava FlowsMissing: landscapes | Show results with:landscapes
[49]
Hawai'i forest review: ecology, evolution, conservation
Andisols develop from ash, cinder, pumice or other ejecta, and weather into soils that hold high amounts of organic matter and water; they support the most ...
[50]
A multi-taxa analysis to identify priority conservation areas in a ...
Preserving and protecting the biodiversity of these fragments may be relevant to promoting the ecological connectivity between the National Parks. However, ...Missing: lava field
[51]
Mass extinctions of life and catastrophic flood basalt volcanism - PNAS
Climatic cooling from volcanic aerosols in the upper atmosphere has been suggested, as has warming resulting from magmatic carbon dioxide emissions. However, ...<|separator|>
[52]
Unraveling the rapid CO2 mineralization experiment using ... - Nature
Apr 6, 2024 · Available studies demonstrate that natural reactions involving basalts on the Earth's surface account for 30–35% of natural CO2 sequestration ...
[53]
[PDF] HAWAIIAN VOLCANIC AGGREGATES
The great historic lava flows of Hawaii have usually originated from rifts or cracks along the flanks of Mauna Loa in one or more lava or fire fountains (See ...
[54]
As Mauna Loa erupts, Native Hawaiians honor their natural and ...
Dec 2, 2022 · For many, the lava flow is a time to pray, sing, dance and make offerings to Pele, the Hawaiian deity of volcanoes and fire.
[55]
Adding Crushed Rock to Farmland Pulls Carbon Out of the Air
Oct 24, 2023 · UC Davis researchers find adding crushed volcanic rock to farmlands can remove carbon dioxide from the air. This 'enhanced' rock weathering works even in dry ...Missing: human significance lava extraction indigenous landscapes 2020s
[56]
Laki, Iceland - 1783 | Volcano World - Oregon State University
The Laki eruption lasted eight months during which time about 14 cubic km of basaltic lava and some tephra were erupted. Haze from the eruption was reported ...Missing: field composition
[57]
Columbia River basalts | Idaho State University
The Columbia River basalts were deposited between 17.5 and 6 million years ago and cover an area of approximately 210,000 km2. Five main episodes of ...
[58]
[PDF] Revisions in Stratigraphic Nomenclature of the Columbia River ...
The age of the group is revised to early, middle, and late Miocene, on the basis of potassium- argon dates ranging from about 16.5 to about 6 m.y. and ...
[59]
[PDF] Overview of Columbia River Basalts (Tolan et al., 2009)
The Miocene Columbia River Basalt Group (CRBG) covers a large part of Ore- gon, Washington, and Idaho and is one of the youngest and perhaps the best studied.
[60]
[PDF] Holocene-Neogene volcanism in northeastern Australia
The Pliocene-Holocene volcanism in southeastern Australia (the Newer Volcanics) and northern Queensland are both widespread, covering >19,000 and >20,000 km2,.Missing: Tooi | Show results with:Tooi
[61]
Nulla Volcanic Province
... lava flows covering an area of 7,500 km2. The youngest volcano, Toomba, is only 13,000 years old, and produced a massive 120 km long lava flow. Three other ...Missing: field | Show results with:field
[62]
Lava rise ridges of the Toomba basalt flow, north Queensland ...
Nov 10, 1998 · Unusually long lava rises occur in the distal portion of the Toomba basalt flow, up to 120 km from the source. In the Lolworth creek region, ...Missing: Holocene | Show results with:Holocene
[63]
Did volcanoes kill the dinosaurs? New evidence points to 'maybe'
Mar 4, 2019 · Keller, a professor of geosciences, has argued for decades that the eruption of the Deccan Traps caused the dinosaur mass extinction.
[64]
[PDF] An evaluation of Deccan Traps eruption rates using geochronologic ...
Apr 16, 2021 · The Deccan Traps, India, is the youngest LIP that is temporally associated with a mass extinction, spanning the Cretaceous–Paleogene Boundary ( ...
[65]
[PDF] Triggering of the largest Deccan eruptions by the Chicxulub impact
Apr 30, 2015 · The Cretaceous-Paleogene mass extinction, the Chicxulub impact, and the enormous Wai. Subgroup lava flows of the Deccan Traps conti- nental ...
[66]
Volcanoes of the San Francisco volcanic field | AZGS
The majority of vents in the field are monogenetic, short-lived cinder cones, such as Sunset Crater. The eastern part of the field formed during the Pleistocene ...
[67]
[PDF] A Geologic Field Guide to S P Mountain and its Lava Flow, San ...
Though the San Francisco Volcanic Field has more than 600 volcanic vents and flows, this guide will focus on S P Mountain (known locally as S P Crater, located ...
[68]
Volcanology and associated hazards of the San Francisco volcanic ...
Sep 4, 2019 · Within the ~5000 km2 area, more than 600 volcanoes are primarily monogenetic and basaltic, but silicic stratovolcanoes and domes are present as ...
[69]
Magnetotelluric support for edge-driven convection and shear ...
Apr 4, 2023 · Within Australia, the threat of eruptions is largely contained within the Newer Volcanics Province (NVP) of southeast Australia, a young (4.5 ...
[70]
The Origin of Intraplate, Monogenetic Volcanism in Southeastern ...
The Newer Volcanic Province (NVP) is the youngest and most extensive occurrence of Cenozoic intraplate volcanism in Australia. This widespread (15,000 km2) ...Missing: threats | Show results with:threats
[71]
Volcano tectonic setting of the intraplate, Pliocene‐Holocene, Newer ...
Jul 30, 2008 · The Pliocene-Holocene Newer Volcanic Province in Victoria, southeast Australia, is a wide volcanic field site of the most recent volcanic activity of Australia.Missing: Tooi | Show results with:Tooi
[72]
Fagradalsfjall - Global Volcanism Program
During 23-31 July the lava effusion rate decreased to 5 m3/sec and the total erupted volume was about 15.9 million m3. The flow field covered an area of 1.5 km2 ...
[73]
Report on Fagradalsfjall (Iceland) — September 2022
Sep 30, 2022 · The area of the flow field was about 4.85 km2, and the total volume erupted was 150 million cubic meters, based on 30 September measurements.
[74]
Fagradalsfjall Continues to Erupt - NASA Earth Observatory
Jul 2, 2021 · As of June 15, the lava flows were estimated to cover a total area of 3 square kilometers (about 1 square mile), with an estimated volume of 63 ...