Depth Extent Research Articles

Integrated geologic and geophysical modeling across the Bartlett Springs fault zone, northern California (USA): Implications for fault creep and regional structure

Abstract The rate and location at depth of fault creep are important, but difficult to characterize, parameters needed to assess seismic hazard. Here we take advantage of the magnetic properties of serpentinite, a rock type commonly associated with fault creep, to model its depth extent along the Bartlett Springs fault zone, an important part of the San Andreas fault system north of the San Francisco Bay, California (western United States). We model aeromagnetic and gravity anomalies using geologic constraints along 14 cross sections over a distance of 120 km along the fault zone. Our results predict that the fault zone has more serpentinite at depth than inferred by geologic relationships at the surface. Existing geodetic models are inconsistent and predict different patterns of creep along the fault. Our results favor models with more extensive creep at depth. The source of the serpentinite appears to be ophiolite thrust westward and beneath the Franciscan Complex, an interpretation supported by the presence of antigorite, a high-temperature serpent ine mineral stable at depth, in fault gouge near Lake Pillsbury.

Crustal structure of onshore-offshore Atlantic Canada and environs from constrained 3-D gravity inversion using variable mesh depths

SUMMARYAtlantic Canada encompasses geological evidence of the orogenic and rifting episodes that inspired the development of the theory of plate tectonics and the fundamental concept of the Wilson cycle. To provide a regional crustal-scale view that can complement surface mapping studies and sparse seismological investigations, an onshore–offshore 3-D constrained gravity inversion methodology is proposed involving incorporation of topography and an inversion mesh that is laterally variable in terms of its maximum depth extent. A 3-D density anomaly model for the entirety of Atlantic Canada and its environs is generated, with the inverted density distribution structure and extracted isodensity surfaces showing excellent correspondence with independent and co-located controlled source and passive seismic constraints. The full density model and crustal thicknesses from this work are made freely available so that they may be used for further study, for instance as inputs for deformable plate reconstruction modelling.

Kinematic Rupture Model of the 6 February 2023 Mw 7.8 Türkiye Earthquake from a Large Set of Near-Source Strong-Motion Records Combined with GNSS Offsets Reveals Intermittent Supershear Rupture

ABSTRACT The 2023 Mw 7.8 southeast Türkiye earthquake was recorded by an unprecedentedly large set of strong-motion stations very close to its rupture, opening the opportunity to observe the rupture process of a large earthquake with fine resolution. Here, the kinematics of the earthquake source are inferred by finite-source inversion based on strong-motion records and coseismic offsets from permanent Global Navigation Satellite Systems stations. The strong-motion records at stations NAR and 4615, which are the closest to the splay fault (SPF) where the rupture initiated and which were previously interpreted to contain the signature of supershear rupture speeds, are successfully modeled here by a subshear rupture propagating unilaterally to the northeast. Once the rupture on the SPF reaches the east Anatolian fault (EAF), it propagates on the EAF bilaterally, extending about 120 km northeast and 180 km southwest. To the south, the depth extent of the rupture decreases, as it passes a bend of the EAF. Although the rupture velocity remains globally subshear along the EAF, we identify three portions of the fault where the rupture is transiently supershear. The transitions to supershear speed coincide with regions of reduced fault slip, which suggests supershear bursts generated by the failure of local rupture barriers. Toward the southwest termination, the rupture encircles an asperity before its failure, which is a feature that has been observed only on rare occasions. This unprecedented detail of the inversion was facilitated by the proximity to the fault and the exceptional density of the accelerometric network in the area.

Geobody estimation by Bhattacharyya method utilizing nonlinear inverse modeling of magnetic data in Baba-Ali iron deposit, NW Iran

One of the essential geophysical concerns is the estimation of the physical and geometrical parameters of the reserve (geobody), which is done by exploiting the nonlinear inverse modeling of magnetic data. The present study includes preparing and modeling magnetic data to suggest the Baba Ali Iron ore deposit's drilling locations in NW Iran. The area is covered with 1000 points of geomagnetic reading with an almost 5 × 10 m2 regularly spaces grid trending WE. The areal and depth extent of the iron ore geobody was unknown. The Bhattacharyya method by MATLAB software coding was employed to underestimate the misfit function and re-construct potential field data, providing the most suitable fitting with measured magnetic data. In this order, the residual calculated anomaly exhibited an excellent two-dimensional conformation with forward modeling. Furthermore, 3D modeling correctly reconstructs the anomalies' productive resources' properties. After preparing full magnetic maps, the magnetic lenses distinguished in four anomalies of surface depths, 20, 50, and deeper than 50 m for this zone. This magnetite lens for the first zone was estimated based on analytical signal filters applied on the entire magnetic map so that the lens's depth is trivial and almost zero. Due to specific gravity calculated as 4.77 t/m3, initial storage capacity is suggested to be about 95,400 tons of magnetite, pyrite, and hematite minerals at most in an area about 6 Km2. Finally, to complete the preliminary explorations of the specified area, exploratory drilling is suggested for three points by inverse modeling. Regarding this study as the first try in magnetic reconnaissance step of Iron mineral exploration in the study area, there is no geological constraints available based on drilling evidences. However, the model is well satisfies the surface anomalies considering residual magnetic property.

Analysis and Interpretation of Regional Gravity Data in the Swayze greenstone belt of the Superior Province, Canada

The Swayze greenstone belt (SGB) is an Archean granitoid-greenstone terrain located in the central part of the Superior Province in Canada. The main objective of this project consisted in doing an analysis and modelling of public regional gravity data of the Swayze greenstone belt with the aim of examining the geometry and depth extent of the geological bodies that occur in the area of this greenstone belt. Gravity data from the Geophysical Data Repository of Natural Resources Canada was used to obtain forward 2.75D gravity models along three profiles, two transversal and one longitudinal to the geological structures of the Swayze greenstone belt. Gravity forward modelling along these profiles was performed using different constraints such as mapped geological contacts at the surface and petrophysical data of different type of rocks of the Abitibi greenstone belt. The models provide an attempt to characterize the geometry and depth extent of the geological units composing the SGB, using regional gravity data.

Newly discovered shallow creep along the Gozha Co fault in northwestern Tibet: Spatial extent, rate and temporal evolution

Whereas most continental faults are interseismically locked, some exceptions have been observed to exhibit aseismic slip over a range of depths in the Earth's upper crust, i.e. shallow creep. This unusual slip behaviour helps probe frictional properties of natural faults. Here, we investigate the kinematic features of a newly discovered shallow creeping fault, the Gozha Co fault in northwestern Tibet, using Sentinel-1 radar interferometry. High-resolution velocities derived from 4 tracks of Sentinel-1 data reveal a 120-km-long creeping section on the Gozha Co fault, with a mean surface fault-parallel rate of ∼3 mm/yr. We use a simple elastic dislocation model to invert for the rate and depth extent of creep. Results show that creep occurs at all depths in the crust at the tectonic loading rate, ∼5 mm/yr, indicating that the discovered shallow creep is steady-state in response to continued tectonic loading, which is supported by the analysis of surface creep time-series that yields a time-independent creep rate. The Sentinel-1 velocities also show that the Longmu Co fault, part of the commonly called Longmu-Gozha Co fault system, has no measurable motion, and therefore may be inactive. Present-day deformation within the Tianshuihai Terrane, 3.8±0.8 mm/yr E-W shear and 0.6±0.6 mm/yr N-S shortening as the GPS velocities show, is in fact accommodated by motion on the Gozha Co fault.

The important boundary role of Lianhuashan fault zone in late Mesozoic magmatism of South China: New insights from ambient noise tomography and teleseismic data

The Lianhuashan fault zone (LHSFZ), which divides the Cathaysia Block (CB) into the coastal volcanic and Cathaysian fold belts, is an important intraplate lineament in the CB. Its fine structure is crucial to understand the Late Mesozoic tectonic evolution of South China. Herein, the fine S-velocity structure of the LHSFZ above 6.0 km and its depth extent were studied by ambient noise tomography and teleseismic relative travel-time residual analysis using a dense (∼1 km station spacing) seismic array spanning 123 km at the southern end of the LHSFZ. Our results indicate that the area within 70 km of the coast has a higher S-wave velocity, which extends to the southeast below 6 km. We propose that the high velocity anomaly is a result of magma intrusion caused by the subduction of the Paleo-Pacific plate in the Late Mesozoic, and the magma upwelling trajectory occurs from the coast to the inland. In addition, a low-velocity anomaly is found beneath the core area of the LHSFZ at a depth of 3–6 km, which is more evident in the S-wave than in the P-wave and corresponds well with the presence of hot springs and earthquakes. We hypothesize that the low-velocity anomaly represents the existing fault system of the Late Mesozoic volcanoes, which now provides channels for fluid migration and facilitates seismicity. Our model suggests that the LHSFZ plays a key role in the evolution of the coastal areas of South China.

Shallow depth extent of the Lesutoskraal granophyre dike in the Vredefort impact structure: Geophysical surveys and trenching data

AbstractRecent observations and geophysical studies at the Vredefort impact structure have indicated that the impact melt dikes in the central uplift of the structure have small depth extents. In this study, we performed magnetic and electrical resistivity tomography (ERT) surveys of the Lesutoskraal granophyre dike (LGD) and trenched to confirm its depth extent. The ERT survey showed that outcrops of the LGD are associated with shallow resistive zones with <3 m depth extent, but such zones do not occur where outcrops are absent. Visual observations in the trench confirmed that the dike has a small depth extent (~0.75 m) at this location. However, the magnetic survey revealed anomalies along the entire strike of the dike, even where no outcrops occur. We suggest that remagnetization of the host rock within a metamorphic contact aureole could explain the presence of magnetic anomalies in the absence of outcrops. Considering the results of the ERT survey, the observations made in the trench, and the surface distribution of outcrops of the LGD, we confirm that this dike has a small depth extent (<3 m) along its entire length and propose that outcrops represent the intersection of the dike terminus with the current erosional surface.

The Thermal Regime of NW Canada and Alaska, and Tectonic and Seismicity Consequences

AbstractNW Canada and Alaska are the continuation of the North American Cordillera through Mexico, western USA and western Canada. I show that they have similar thermal regimes and thermal control of tectonics and seismicity. I first summarize the multiple constraints to crust and upper mantle temperatures and then discuss some consequences. There are bimodal crust and upper mantle temperatures characteristic of most subduction zones: cool forearc, uniformly hot backarc (Yukon Composite Terrane to Southern Brooks Range, and Mackenzie Mountains), and stable cratonic backstops (Arctic Alaska Terrane and Canadian Shield). The main constraints are as follows: (a) Heat flow measurements, (b) Temperature‐dependent upper mantle velocities and seismic attenuation, (c) Temperature‐dependent topographic elevations; thermal isostasy, (d) Depth and temperature of the seismic lithosphere‐asthenosphere boundary (LAB), (e) Origin temperature and depth of craton kimberlite xenoliths, (f) Geochemically inferred source temperature and depth of recent volcanic rocks. (g) Depth to the magnetic Curie temperature, (h) Depth extent of seismicity. The backarc lithosphere is thin, LAB at 50–85 km and ∼1,350°C ± 25°C. Moho temperatures at 35 km are 850°C ± 100°C compared to cool cratonic areas of 400°C–500°C. The consequences include the following: (a) Thin and weak backarc lithosphere that accommodates pervasive tectonic deformation indicated by wide‐spread seismicity and GPS‐defined motions, in contrast to the stable cratonic regions; (b) Weak backarc lower crust that flattens the Moho and allows detachment and thrusting of the upper crust over the cold strong Arctic Alaska Terrane and Canadian Shield. This article provides a model for how to estimate deep temperatures from multiple constraints.

Earthquake-Triggered Crustal Shear Velocity Change at the Erupting Turrialba Volcano

ABSTRACT Monitoring variations in seismic velocities surrounding active volcanoes provides insights into crustal deformation caused by eruptions and earthquakes. Turrialba volcano in Costa Rica has been erupting sporadically since 2010 and experienced a local seismic swarm in 2016, including the Mw 5.5 Capellades earthquake. It is thus an ideal natural laboratory to study crustal velocity changes associated with a seismic event at an active volcano. We use seismic noise-generated surface waves to characterize emergent upper crustal velocity variations following the earthquake sequence off the flank of the volcano. Our study highlights a rapid velocity drop immediately following the earthquake implying widespread damage and/or a readjustment of local stress. From the frequency dependence of surface waves, we find that the depth over which the velocities vary is localized to the upper ∼2.5 km of the crust, coinciding with the depth extent of the Capellades earthquake aftershock sequence as well as the shallow magma chamber feeding the Turrialban eruption. From the areal extent of the velocity decrease, crustal variations are likely tied to both damage following the seismic sequence and the evolution of the shallow magma reservoir feeding Turrialba.

Wet mantle transition zone beneath the Indian shield: Constraints from P-to-S receiver functions analysis

Indian plate passed over four plumes on its way toward the Eurasian plate. These interactions with plumes certainly affected the upper mantle and crust of the Indian plate as manifested by its thinned lithosphere and relatively low shear velocities both in the crust and upper mantle, but the depth extent of these effects of plume-lithosphere interaction remains ambiguous. In this study, we investigate the mantle transition zone beneath the Indian shield using P receiver functions computed at 23 stations covering the entirety of the Indian shield to investigate the depth extent of the imprints of the plume-lithosphere interaction as well as to study the lateral variations of transition zone beneath a stable intraplate setting like the Indian shield. Our results show good agreement with the results of previous studies as well as with the tomographic models in terms of the average apparent depths of the 410 and 660 discontinuities and the transition zone thickness. However, unlike previous studies, we find compelling evidence of a persistent mid-transition zone discontinuity beneath all the stations and a low-velocity layer beneath some regions. We also investigated the frequency dependence of amplitudes of receiver functions and found that most of the stations showed a strong dependence of amplitudes on frequency. Based on the evidence from our investigation, we demarcate the regions potentially containing relatively more weight percentage of water inside the otherwise considered as a ‘dry’ mantle transition zone. These regions should be further investigated in detail by a dense seismic network and a realistic 3-D velocity model.

Small crater relaxation and ice abundance at high northern latitudes on Mars

The cold, northern high-latitudes around the Phoenix landing site feature a population of small and very shallow craters known as palimpsest craters or boulder halos that could give insight into the subsurface ice content of the region. Notably there is also a split in the population by the size of craters that feature blocky ejecta: the smallest crater sizes that are <200–350 m in diameter typically do not feature blocky ejecta, while craters larger than this size range do. This has been interpreted as there being a less consolidated layer of mainly ice that sits over a more consolidated layer containing more silicate material from which the larger craters are able to excavate the blocky ejecta. This work focuses on determining whether these 200 m - 1 km shallow craters could be indicative of topographic relaxation due to substantial ice in the subsurface, with goals to determine the subsurface structure and most importantly the amount of ice present through its abundance and depth extent. We use finite element modeling of axisymmetric simple craters, employing the most recent characterizations of solid-state creep for water ice, silicate-rich ice, and CO2 ice, to determine the timescales and magnitudes of relaxation accommodated by an icy single or multiple material layered subsurface to determine the environment's properties. Our models include a 35 m thick layer of pure ice (water, or water and CO2) over a mobile substrate of particulate rich water ice of variable thicknesses able to accommodate relaxation for larger crater sizes up to 1 km in diameter. Our findings demonstrate that relaxation is able to account for significant flattening of crater topography, though for smaller craters the relaxation is incomplete, leaving about half the depth. The accommodated relaxation of our modeled subsurface does imply associated increases in ice abundances of 4 to 10 times greater than is currently estimated for the region, dependent on the extent of the mobile layer.

Structure and Dynamics of Lithosphere and Asthenosphere in Asia: A Seismological Perspective

AbstractKnowledge of lithospheric structure is essential for understanding the impact of continental collision and oceanic subduction on surface tectonic configurations. Full‐waveform tomographic images reveal lateral heterogeneities and anisotropy of the lithosphere and asthenosphere in Asia. Estimating lithospheric thickness from seismic velocity reductions at depth exhibits large variations underneath different tectonic units. The thickest cratonic roots are present beneath the Sichuan, Ordos, and Tarim basins and central India. Radial anisotropy signatures of 11 representative tectonic provinces uncover the different nature and geodynamic processes of their respective past and present deformation. The large‐scale continental lithospheric deformation is characterized by low‐velocity anomalies from the Himalayan Orogen to the Baikal rift zone in central Asia, coupled with the post‐collision thickening of the crust. The horizontal low‐velocity layer of ∼100–300 km depth extent below the lithosphere points toward the existence of the asthenosphere beneath East and Southeast Asia, with heterogeneous anisotropy indicative of channel flows.

Neutrophil-like Biomimic AIE Nanoparticles with High-Efficiency Inflammatory Cytokine Targeting Enable Precise Photothermal Therapy and Alleviation of Inflammation.

Although photothermal therapy (PTT) has thrived as a promising treatment for drug-resistant bacterial infections by avoiding the abuse of antibiotics, the remaining challenges that limit the treatment efficiency are the poor targeting properties of infected lesions and low penetration to the cell membrane of Gram-negative bacteria. Herein, we developed a biomimetic neutrophil-like aggregation-induced emission (AIE) nanorobot (CM@AIE NPs) for precise inflammatory site homing and efficient PTT effects. Due to their surface-loaded neutrophil membranes, CM@AIE NPs can mimic the source cell and thus interact with immunomodulatory molecules that would otherwise target endogenous neutrophils. Coupled with the secondary near-infrared region absorption and excellent photothermal properties of AIE luminogens (AIEgens), precise localization, and treatment in inflammatory sites can be achieved, thereby minimizing damage to surrounding normal tissues. Moreover, CM@AIE NP-mediated PTT was stimulated in vivo by a 980 nm laser irradiation, which contributed to the extent of the therapeutic depth and limited the damage to skin tissues. The good biocompatibility and excellent in vitro and in vivo antibacterial effects prove that CM@AIE NPs can provide a strategy for broad-spectrum antibacterial applications.

Rapid along-strike variations of shallow crustal structure in response to Indo-Burma subduction: Constraints from multi-type passive seismic data

Characteristics of the subducting crust and the attached sedimentary cover play a key role in shaping the structure and processes in the hanging wall of a convergent plate boundary. Such influence must be significant in the oblique Indo-Burma subduction zone. Yet, the poorly resolved shallow crustal velocity structure of the overriding Burma plate, especially its lateral variation along the subduction margin, hinders a comprehensive understanding of the Indo-Burma subduction dynamics. Here, we take advantage of the new and dense broadband seismic data in Myanmar to image the regional S-wave velocity (Vs) structure in the top 10 km of crust by joint inversion of Rayleigh-wave ellipticity, receiver function and P-wave polarization. The new velocity model not only matches surface geology and seismic reflection profiles, but also reveals new and rapidly varying near-surface features, including (1) the exhumed high-velocity metamorphic belt of the Indo-Burma accretionary prism, which is more prominent in the south with a shallower depth extent and greater Vs of ∼3.5 km/s; and (2) contrasting Vs structure beneath the two Quaternary volcanoes, that is, Vs of typical crystallized igneous rocks (∼3 km/s) beneath Monywa versus Vs slower than the adjacent basin sediments (<2.5 km/s) under Mt. Popa. Combining with existing knowledge, we propose that the observed along-strike changes in the shallow forearc structure could be attributed to the northward increase of the off-scraped/underplated Ganges-derived Bengal sediments in the inner accretionary prism and the uneven distribution of the sediment-derived fluids, the majority of which may be trapped within the prism in the north but be subducted to deeper sub-arc level in the south. These eventually result in slower exhumation of the metamorphic belt and less active shallow crustal magmatism in the north than the south. Further, we speculate that the Bengal sediment behavior and the upper plate crustal structure might be modulated by a transition of the incoming Indian plate from the continental lithosphere beneath Tibet and northern Myanmar to thin continental/oceanic nature in the south.

Increasing depth distribution of Arctic kelp with increasing number of open water days with light

Kelps are a dominant macrophyte group and primary producer in Arctic nearshore waters that provide significant services to the coastal ecosystem. The quantification of these services in the Arctic is constrained, however, by limited estimates of kelp depth extent, which creates uncertainties in the area covered by kelp. Here, we test the environmental drivers of the depth extent of Arctic kelp. We used Southampton Island (SI), Nunavut, Canada, as an example region after an initial survey found deep Arctic kelp (at depths to at least 50 m) with relatively low grazing pressure within diverse hydrographic conditions. We found abundant rocky substrata, but no influence of substratum type on kelp cover. The kelp cover increased with depth until 20 m and then decreased (the median maximum depth for all stations was 37 m). The best predictor of kelp depth extent was the number of annual open (ice-free) water days with light (r2 = 44–52%); combining depth extent data from SI with published data from Greenland strengthened this relationship (r2 = 58–71%). Using these relationships we estimated the maximum kelp-covered area around SI to be 27,000–28,000 km2, yielding potential primary production between 0.6 and 1.9 Tg Cyr−1. Water transparency was a key determinant of the underwater light environment and was essential for explaining cross-regional differences in kelp depth extent in SI and Greenland. Around SI the minimum underwater light required by kelp was 49 mol photons m−2 yr−1, or 1.4% of annual integrated incident irradiance. Future consideration of seasonal variation in water transparency can improve these underwater light estimations, while future research seeking to understand the kelp depth extent relationship with nutrients and ocean dynamics can further advance estimates of their vertical distribution. Improving our understanding of the drivers of kelp depth extent can reduce uncertainties around the role of kelp in Arctic marine ecosystems.

Concurrent elastic inversion of Rayleigh and body waves with interleaved envelope-based and waveform-based misfit functions

Rayleigh and body waves are both solutions of the same propagation equation, but correspond to different wavenumber regions and boundary conditions, so their interaction with the elastic parameters (Vp, Vs and density) provides independent constraints during inversion. We develop and illustrate concurrent, elastic, full-waveform inversion of P and S body- and Rayleigh-waves using interleaved envelope- and waveform-based misfit functions, in a gradually-increasing frequency, multi-scale, inversion strategy. A wavelet and its envelope have different effective bandwidths, spectral shapes, and provide complementary frequency and wavenumber weighting in concurrent inversion. Because of the greater depth extent sampled by the exponentially decaying tail of a Rayleigh wave, compared to a body waveform, the depth extent of the model required to support both body and surface waves in concurrent inversion is defined by the Rayleigh waves. Correlation coefficients provide quantitative measures of the contributions of the data subsets to the fits of the solutions. For both smooth and constant starting models, concurrent interleaved inversion gives smaller data misfits than the envelope-only and waveform-only solutions. Treating the whole wavefield as a single data set means that it is not necessary to separate, or even to identify, different types of body and surface waves.

Laser fluorescence is a predictor of lesion depth in non-cavitated root carious lesions - an in vitro study.

This in vitro study was designed to compare the assessment of carious root surfaces using laser fluorescence or visual assessment and µCT. A total of 107 extracted human teeth were included in the study. For the subsequent assessment, a clinical evaluation according to Ekstrand and Nyvad criteria, laser fluorescence measurements (DIAGNOdent-Pen©), and µCT imaging (Bruker Skyscan 1172) of the included root surfaces were performed. For cavitated lesions, the surface was reconstructed on µCT. Target parameters were: clinical appearance, laser fluorescence reading (0-99), and lesion depth in µm (µCT). The statistical analysis included chi² and Spearman-Rho tests. Laser fluorescence values were significantly higher (p<0.01) in leathery non-cavitated (median [IQR]: 73.50 [48.00]) and cavitated (88.50 [29.00]) surfaces than in hard intact surfaces (7.00 [35.00]). In addition, laser fluorescence values showed a significant correlation with lesion depth for non-cavitated surfaces (0.750; p<0.01). Further statistically significant correlations were not detectable. Regression analysis showed that the laser fluorescence values increased with increasing demineralization depth (β: 0.648, CI95: 0.631-1.053; p<0.01). Laser fluorescence measured by DIAGNOdent© is a predictor for the depth of demineralization in carious root caries lesions with intact surfaces. Considering the limitations of this in vitro study, laser fluorescence is suitable for assessing the depth extent of (non-cavitated) root caries lesions and is a tool for clinical diagnosing and assessing the course of lesion development.

Binocular treatment for amblyopic children: a review.

The narrative review was planned to investigate the efficiency of binocular treatment for amblyopic children, and to compare it with the standard methods. Literature search was conducted for articles in English language available on PubMed, Cochrane Library, Embase, Medline and PsycInfo databases as well as through bibliographies of peer-reviewed studies. Studies in the field of binocular treatment for amblyopia were included. Visual outcomes considered were visual acuity, types of amblyopia and stereoacuity. Studies on deprivation amblyopia, animal studies, literature review of amblyopia treatment, case reports, and trials targeting participants in whom previous amblyopia treatment had failed were excluded. Of the 40 studies found, 21(52.5%) met the inclusion criteria. Visual acuity and binocular function improved with binocular treatment for treating amblyopia in children by decreasing suppression depth extent and increasing stereopsis. Binocular treatment for amblyopic children was found to be an effective and fast process for the recovery of visual functions, especially in the critical time of visual development.

Soil organic carbon stocks by soil group for afforested soils in Ireland

Forest ecosystems are recognised as Natural Climate Solutions because forest soils are such important carbon stores, containing almost half of the total soil organic carbon of terrestrial ecosystems. Here we present the results of a synthesis of soil carbon stocks by World Reference Base soil group, and forest litter carbon stocks for afforested soils in the Republic of Ireland. We report soil carbon stocks of mineral soils separately from organo-mineral soils. We estimated mean soil carbon stocks in a 100 cm deep mineral soil to be between 162 ± 87 t C/ha (Gleysols) and 416 ± 0 t C/ha (Umbrisols, n = 1), and between 173 ± 65 t C/ha (Phaeozems) and 602 ± 226 t C/ha (Regosols) in a 100 cm deep organo-mineral soil; both less than the estimated soil carbon stocks in organic soils (Histosols): 645 ± 222 t C/ha. The entire soil carbon stocks in mineral Leptosols (100 ± 0 t C/ha, n = 1), Stagnosols (144 ± 39 t C/ha), Luvisols (159 ± 52 t C/ha) and Fluvisols (231 ± 0 t C/ha, n = 1) was contained in the upper 50 cm of soil. Based on a 100 cm deep soil, Histosols hold 1.6–4 times the amount of soil C than mineral soils and 1.1–3.7 times the amount in organo-mineral soils for the same profile depth. Certain mineral (e.g. Umbrisols) and organo-mineral soils (e.g Gleysols, Regosols) contain substantial soil carbon stocks relative to Histosols. We found considerable soil carbon stocks below 30 cm depth, which highlights the importance of depth extent for cumulative soil carbon stocks estimates. The upper third of the 100 cm profile contained 33% (Histosols) to 70% (Luvisols) of the soil carbon stocks and the upper half of a 100 cm profile contained the entire soil carbon stocks for Leptosols, Stagnosols, Luvisols and Fluvisols and organo-mineral Leptosols. Unfortunately, there were few samples available for mineral Leptosols, Umbrisols, Luvisols and Fluvisols, and the organo-mineral Stagnosols and Regosols, which precludes the drawing of conclusions for these groups. Relative to the soil carbon stocks, we found low mean forest litter stocks: 4.1 ± 5.5 t C/ha, 4.8 ± 3.3 t C/ha and 2.7 ± 2.9 t C/ha for broadleaf, coniferous and mixed forests respectively. Few exceptions existed for individual sites: 22.7 and 131.3 t C/ha for broadleaf forests. Our results are evidence that soil carbon stocks in mineral, organo-mineral and organic soils need to be protected, appropriately managed, and enhanced to be beneficial for greenhouse gas mitigation. Assessments are needed to identify which soil-site-management practice combinations risk soil carbon stock depletion. The large range observed in soil and litter carbon stocks stresses the importance of adequately accounting for soil group differences when GHG inventories are compiled. The synthesised dataset will contribute to improved SCS estimation for afforested lands in Ireland.