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Daniel F Stockli - One of the best experts on this subject based on the ideXlab platform.
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applications and limitations of u pb Thermochronology to middle and lower crustal thermal histories
Chemical Geology, 2018Co-Authors: Andrew J Smye, Pieter Vermeesch, Jeffrey Marsh, J M Garber, Daniel F StockliAbstract:Abstract Volume diffusion of Pb occurs over micron length scales in apatite and rutile at temperatures relevant to the evolution of the middle and lower crust. Continuous thermal history information can be resolved from inversion of intracrystalline U-Pb date profiles preserved within individual grains. Recent developments in microbeam analysis permit rapid measurement of these age profiles at sub-micron spatial resolution, thus heralding a new era for U-Pb Thermochronology. Here, we review the theoretical, experimental and empirical basis for U-Pb Thermochronology and show that rutile, in particular, presents an exceptional opportunity to obtain high-resolution thermal history information from the deep crust. We present a Bayesian procedure that is well suited to the inversion of U-Pb date profile datasets and balances computational efficiency with a full search of thermal history coordinate space. Complications relevant to accurate application of U-Pb Thermochronology are discussed i) theoretically and ii) empirically, using a rutile U-Pb dataset from the lower crust of the Grenville orogeny. Purely diffusive date profiles are shown to be the exception to uniform, or step-like, young profiles, suggesting that processes other than thermally-activated volume diffusion may control U-Pb systematics in rutile residing in the lower crust. However, the data obtained from apparent diffusive profiles systematically match cooling histories inferred from other thermochronometers. This result emphasises the importance of integrating microtextural observations, and trace-element concentrations, with U-Pb age data in order to discriminate between diffusive and non-diffusive Pb transport mechanisms in accessory phases and thus minimize the risk of generating spurious thermal histories.
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Low-temperature Thermochronology of Anticosti Island: A case study on the application of conodont (U-Th)/He Thermochronology to carbonate basin analysis
Marine and Petroleum Geology, 2018Co-Authors: Jeremy Powell, James R. Metcalf, Fred Gaidies, André Desrochers, Rebecca M Flowers, David Schneider, Daniel F StockliAbstract:Abstract The Ordovician to Silurian carbonate succession preserved on Anticosti Island is a near continuous record of the changing depositional and tectonic history of the Early Paleozoic Laurentian margin. These strata are a prime natural laboratory to test the applicability of conodont apatite (U-Th)/He Thermochronology (CAHe) for carbonate basin analysis in a setting with a well-understood burial history and abundant paleotemperature constraints. We report 63 CAHe dates from seven samples collected from two boreholes. X-ray micro-computed tomography (XR-μCT) was used to assess individual conodont element size, volume and alpha ejection correction. CAHe dates are negatively correlated with effective uranium concentration (eU), with single conodont dates enigmatically older than the age of deposition to conodont dates as young as 2.7 ± 0.2 Ma. We rationalize this dispersion as a product of several factors, including diagenetic processes and pervasive conodont crystalline porosity and permeability. Additionally, one basement and two sandstone samples were collected for apatite and zircon (U-Th)/He (AHe, ZHe) and apatite fission track (AFT) Thermochronology. In the Precambrian basement, ZHe dates range from 581.7 ± 46.5 Ma to 761.2 ± 60.9 Ma (n: 4) and AHe dates range from 26.7 ± 1.6 to 48.4 ± 2.9 Ma (n: 4). AHe dates from two Lower Ordovician sandstones (n: 8) are positively correlated with eU, increasing from 13.7 ± 0.8 Ma to 105.2 ± 6.3 Ma over a range of 186 ppm eU. Thermal history modeling of these data suggests two plausible thermal histories, both of which are novel as they imply that far-field effects related to the opening of the Atlantic Ocean have influenced the thermal history of Anticosti Island. Ultimately, these data highlight the complexities associated with, and necessity of, low-temperature Thermochronology in carbonate basins.
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constraints on the magnitude and rate of co2 dissolution at bravo dome natural gas field
Proceedings of the National Academy of Sciences of the United States of America, 2014Co-Authors: Kiran J Sathaye, Marc A Hesse, Martin Cassidy, Daniel F StockliAbstract:The injection of carbon dioxide (CO2) captured at large point sources into deep saline aquifers can significantly reduce anthropogenic CO2 emissions from fossil fuels. Dissolution of the injected CO2 into the formation brine is a trapping mechanism that helps to ensure the long-term security of geological CO2 storage. We use Thermochronology to estimate the timing of CO2 emplacement at Bravo Dome, a large natural CO2 field at a depth of 700 m in New Mexico. Together with estimates of the total mass loss from the field we present, to our knowledge, the first constraints on the magnitude, mechanisms, and rates of CO2 dissolution on millennial timescales. Apatite (U-Th)/He Thermochronology records heating of the Bravo Dome reservoir due to the emplacement of hot volcanic gases 1.2–1.5 Ma. The CO2 accumulation is therefore significantly older than previous estimates of 10 ka, which demonstrates that safe long-term geological CO2 storage is possible. Integrating geophysical and geochemical data, we estimate that 1.3 Gt CO2 are currently stored at Bravo Dome, but that only 22% of the emplaced CO2 has dissolved into the brine over 1.2 My. Roughly 40% of the dissolution occurred during the emplacement. The CO2 dissolved after emplacement exceeds the amount expected from diffusion and provides field evidence for convective dissolution with a rate of 0.1 g/(m2y). The similarity between Bravo Dome and major US saline aquifers suggests that significant amounts of CO2 are likely to dissolve during injection at US storage sites, but that convective dissolution is unlikely to trap all injected CO2 on the 10-ky timescale typically considered for storage projects.
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discriminating rapid exhumation from syndepositional volcanism using detrital zircon double dating implications for the tectonic history of the eastern cordillera colombia
Geological Society of America Bulletin, 2012Co-Authors: Joel E Saylor, Daniel F Stockli, Brian K Horton, Andres MoraAbstract:Lag time is the difference between the closure age of a thermochronologic system and the depositional age of host strata. Lag-time analysis of sedimentary basin fi ll provides insight into the exhumation history of adjacent eroded orogens. In a case study of the Paleogene Floresta basin in the Eastern Cordillera fold-thrust belt of Colombia, variations in lag time refl ect changes in both sediment source areas and exhumation patterns. However, near-zero lag times can be produced by either syndepositional volcanism or rapid exhumation. We applied U-Pb geochronology and (U-Th)/He (ZHe) Thermochronology to individual zircon grains and identifi ed zircons of volcanic origin as those for which the U-Pb age is within the 2σ uncertainty of their ZHe age. Consistent discrimination of young ZHe ages as the products of either rapid exhumation or volcanism reveals three stages in the history of the northern Andean hinterland. (1) Early to late Paleocene: The appearance of syndepositional and Mesozoic volcanic zircons marks the initial infl ux of magmatic arc detritus. (2) Middle to late Eocene: Near-zero lag times point to rapid, regionally extensive exhumation attributable to thrust-induced uplift of the Magdalena Valley basement. (3) Late Eocene to late Oligocene: Increased lag time is interpreted as recycling of shallowly buried foreland-basin strata possibly due to movement on basinbounding thrust systems. The presence of volcanic zircons with ZHe ages younger than or indistinguishable from the youngest exhumationally cooled zircons underscores the need for double dating to reliably identify volcanic infl uence in detrital Thermochronology datasets. These data highlight the utility of double-dated ZHe results for extracting tectonic histories and reliably excluding volcanic zircons from lag-time analysis.
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rapid cooling rates at an active mid ocean ridge from zircon Thermochronology
Earth and Planetary Science Letters, 2011Co-Authors: Axel K. Schmitt, Daniel F Stockli, M R Perfit, K H Rubin, Matthew Smith, Laurie A Cotsonika, Georg F Zellmer, Ian W Ridley, Oscar M LoveraAbstract:article i nfo Oceanic spreading ridges are Earth's most productive crust generating environment, but mechanisms and rates of crustal accretion and heat loss are debated. Existing observations on cooling rates are ambiguous regarding the prevalence of conductive vs. convective cooling of lower oceanic crust. Here, we report the discovery and dating of zircon in mid-ocean ridge dacite lavas that constrain magmatic differentiation and cooling rates at an active spreading center. Dacitic lavas erupted on the southern Cleft segment of the Juan de Fuca ridge, an intermediate-rate spreading center, near the intersection with the Blanco transform fault. Their U-Th zircon crystallization ages (29.3�4.6 +4.8 ka; 1σ standard error s.e.) overlap with the (U-Th)/He zircon eruption age (32.7±1.6 ka) within uncertainty. Based on similar 238
Peter W. Reiners - One of the best experts on this subject based on the ideXlab platform.
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using Thermochronology to understand orogenic erosion
Annual Review of Earth and Planetary Sciences, 2006Co-Authors: Peter W. Reiners, Mark T. BrandonAbstract:Erosion of orogenic mountain ranges exhumes deeply buried rocks and controls weathering, climate, and sediment production and transport at a variety of scales. Erosion also affects the topographic form and kinematics of orogens, and it may provide dynamic feedbacks between climate and tectonics by spatially focused erosion and rock uplift. Thermochronology measures the timing and rates at which rocks approach the surface and cool as a result of exhumation. Relatively well-understood noble gas and fission-track thermochronometric systems have closure temperatures ranging from ∼60 to ∼550 ◦ C, making them sensitive to exhumation through crustal depths of about one to tens of kilometers. Thus, Thermochronology can constrain erosion rates and their spatial-temporal variations on timescales of ∼10 5 –10 7 years, commensurate with orogenic growth and decay cycles and possible climate-tectonic feedback response times. Useful methods for estimating erosion rates include inverting ages for erosion rates using crustal thermal models, vertical transects, and detrital approaches. Spatial-temporal patterns of thermochronometrically determined erosion rates help constrain flow of material through orogenic wedges, orogenic growth and decay cycles, paleorelief, and relationships with structural, geomorphic, or climatic features.
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past present and future of Thermochronology
Reviews in Mineralogy & Geochemistry, 2005Co-Authors: Peter W. Reiners, Todd A Ehlers, Peter K ZeitlerAbstract:In one form or another, geochronologists have been practicing Thermochronology 1 , the use of radioisotopic dating to constrain thermal histories of rocks and minerals, for over 40 years. Building from lessons learned over these four decades, Thermochronology continues to evolve due to technical developments, increasingly sophisticated theoretical models, and an expanding range of applications in geologic and planetary science. Most recently, interest in earth-surface processes and interactions between tectonics, erosion, and climate has drawn attention to techniques that can address the timing and rates of processes operating at temperatures below about 300 °C. The purpose of this RiMG volume is to assess the current state of Thermochronology, as of circa 2005, which is, coincidentally, the 100th anniversary of the first radioisotopic date (Rutherford 1905; 1906). Excellent review papers and books on specific topics within this field have been published, but no single volume has yet provided a comprehensive review of current practices, basic theory, and illustrative examples. The motivation for this volume stems from these considerations. Knowing that in a fast-developing field a book like this can quickly become dated, we tried to include sufficient review of fundamentals and the literature to offer students and new users a useful introduction to Thermochronology that may have some staying power. In this chapter, we first review the salient points of Thermochronology’s history before assessing our current capabilities and challenges and then taking the risk of suggesting where the field is headed. We do not provide a comprehensive history of the method that does full justice to the work of the large and growing cohort of thermochronologists. In this short space, we instead opted to give our perspectives on where the intellectual and technological roots of the discipline lie, which run deeper and go back farther than is sometimes appreciated. …
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zircon u th he thermochronometry
Reviews in Mineralogy & Geochemistry, 2005Co-Authors: Peter W. ReinersAbstract:A number of features of zircon (ZrSiO4), including high U-Th concentrations, high abundance in a wide range of lithologies, refractory nature under metamorphic and some magmatic conditions, and resistance to physical and chemical weathering, make it highly suitable for geochronology and Thermochronology and thus a versatile tool for examining a wide range of earth processes. Like apatite and many other minerals, radioisotopic dating of zircon was first performed using the (U-Th)/He system, but the thermochronologic significance of zircon He ages has emerged only in the last few years. In this chapter, I review the current status of zircon He dating in the earth sciences, primarily as applied to Thermochronology, including the controls on He diffusivity, the role of radiation damage, analytical techniques for measuring zircon He ages, special considerations unique to zircon He dating, and a series of case studies. Several examples from the literature are briefly summarized to illustrate the diversity of geologic problems accessible by zircon He dating and highlight the future potential of the system and outstanding unresolved issues. Exemplary applications include determining the timing and rates of orogenic exhumation and constraining provenance, depositional ages, and source terrain histories using He-Pb double dating of detrital zircons. ### Historical perspective Previous geo- and thermochronometric studies of zircon have utilized a wide range of decay schemes, including Pb-α (e.g., Webber et al. 1956), U/Pb, Pb/Pb, Th/Pb (Larsen et al. 1952; Vinogradov et al. 1952; Tilton et al. 1955; Wetherill 1955; Silver and Deutsch 1963; Parrish and Noble 2003; Ireland and Williams 2003; Bowring and Schmitz 2003), U-series (Scharer 1984; Reid et al. 1997), fission-track (Naeser et al. 1981; Brandon and Vance 1992; Bernet and Garver 2005; Tagami 2005), Lu/Hf (in concert with other phases; e.g., Pettingill and Patchett 1981), Sm/Nd …
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late cenozoic evolution of the eastern margin of the tibetan plateau inferences from 40ar 39ar and u th he Thermochronology
Tectonics, 2002Co-Authors: Michael A Krol, K V Hodges, Peter W. Reiners, Kenneth A. Farley, W. Tang, Kelin X Whipple, Eric Kirby, Zhiliang ChenAbstract:High topography in central Asia is perhaps the most fundamental expression of the Cenozoic Indo-Asian collision, yet an understanding of the timing and rates of development of the Tibetan Plateau remains elusive. Here we investigate the Cenozoic thermal histories of rocks along the eastern margin of the plateau adjacent to the Sichuan Basin in an effort to determine when the steep topographic escarpment that characterizes this margin developed. Temperature-time paths inferred from ^(40)Ar/^(39)Ar Thermochronology of biotite, multiple diffusion domain modeling of alkali feldspar ^(40)Ar release spectra, and (U-Th)/He Thermochronology of zircon and apatite imply that rocks at the present-day topographic front of the plateau underwent slow cooling ( 30°–50°C/m.y.) coincident with exhumation from inferred depths of ∼8–10 km, at denudation rates of 1–2 mm/yr. Samples from the interior of the plateau continued to cool relatively slowly during the same time period (∼3°C/m.y.), suggesting limited exhumation (1–2 km). However, these samples record a slight increase in cooling rate (from <1 to ∼3°C/m.y.) at some time during the middle Tertiary; the tectonic significance of this change remains uncertain. Regardless, late Cenozoic denudation in this region appears to have been markedly heterogeneous, with the highest rates of exhumation focused at the topographic front of the plateau margin. We infer that the onset of rapid cooling at the plateau margin reflects the erosional response to the development of regionally significant topographic gradients between the plateau and the stable Sichuan Basin and thus marks the onset of deformation related to the development of the Tibetan Plateau in this region. The present margin of the plateau adjacent to and north of the Sichuan Basin is apparently no older than the late Miocene or early Pliocene (∼5–12 Ma).
Paul G Fitzgerald - One of the best experts on this subject based on the ideXlab platform.
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low temperature thermal history and landscape development of the eastern adirondack mountains new york constraints from apatite fission track Thermochronology and apatite u th he dating
Geological Society of America Bulletin, 2011Co-Authors: Joshua P Taylor, Paul G FitzgeraldAbstract:The Adirondack Mountains in northern New York State form an elongate, domal exposure of mainly high-grade metamor- phic tectonites in a mountainous setting with topographic relief of ~1 km. The origin of the Adirondack Mountains and this relief has long been enigmatic, since the Adirondacks presently lie within an intracratonic setting, inboard of the North American passive mar- gin and far from any active plate boundaries. Through the application of apatite fi ssion- track (AFT) Thermochronology and apatite (U-Th)/He (AHe) dating within the eastern Adirondack Mountains, this study provides constraints on both the thermal and ero- sional effects of Mesozoic passage near a hot- spot and the timing of relief development. AFT Thermochronology and AHe dating record relatively stable thermal conditions within the eastern Adirondacks from the Middle Jurassic into the Early Cretaceous. During the Early Cretaceous (ca. 130- 120 Ma), the region underwent heating as- sociated with progressive movement near the Great Meteor hotspot, resulting in the temporary establishment of an elevated geo- thermal gradient. Following regional heat- ing, cooling rates increased considerably (ca. 105-95 Ma), likely due to both thermal doming, producing an increase in erosion rate, and the relaxation of isotherms after passage near the hotspot. The regional distribution of AFT ages across the eastern Adirondacks reveals no systematic age gradient from core to periph- ery, which would be expected under con- ditions of persistent high relief during the decay of a crustal root over many tens to hun- dreds of millions of years. Instead, thermo- chronological data suggest that the present relief developed during the Late Cretaceous- Cenozoic through plateau dissection during periodic base-level changes.
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south virgin white hills detachment fault system of se nevada and nw arizona applying apatite fission track Thermochronology to constrain the tectonic evolution of a major continental detachment fault
Tectonics, 2009Co-Authors: Paul G Fitzgerald, Ernest M Duebendorfer, James E Faulds, Paul B OsullivanAbstract:The South Virgin-White Hills detachment (SVWHD) in the central Basin and Range province with an along-strike extent of similar to 60 km is a major continental detachment fault system. Displacement on the SVWHD decreases north to south from similar to 17 to <6 km. This is accompanied by a change in fault and footwall rock type from mylonite overprinted by cataclasite to chlorite cataclasite and then fault breccia reflecting decreasing fault displacement and footwall exhumation. Apatite fission track (AFT) Thermochronology was applied both along-strike and across-strike to assess this displacement gradient. The overall thermal history reflects Laramide cooling (similar to 75 Ma) and then rapid cooling beginning in the late early Miocene. Age patterns reflect some complexity but extension along the SVWHD appears synchronous with rapid cooling initiated at similar to 17 Ma due to tectonic exhumation. Slip rate is more rapid (similar to 8.6 km/Ma) in the north compared to similar to 1 km/Ma in the south. The displacement gradient results from penecontemporaneous along-strike motion and formation of the SVWHD by linkage of originally separate fault segments that have differential displacements and hence differential slip rates. East west transverse structures likely play a role in linkage of different fault segments. The preextension paleogeothermal gradient is well constrained in the Gold Butte block as 18-20 degrees C/km. We present a new thermochronologic approach to constrain fault dip during slip, treating the vertical exhumation rate and the slip as vectors, with the angle between them used to constrain fault dip during slip through the closure temperature of a particular thermochronometer. AFT data from the western rim of the Colorado Plateau. Citation: Fitzgerald, P. G., E. M. Duebendorfer, J. E. Faulds, and P. O'Sullivan (2009), South Virgin-White Hills detachment fault system of SE Nevada and NW Arizona: Applying apatite fission track Thermochronology to constrain the tectonic evolution of a major continental detachment fault, Tectonics, 28, TC2001, doi:10.1029/2007TC002194.
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low temperature Thermochronology and modeling strategies for multiple samples 1 vertical profiles
Earth and Planetary Science Letters, 2005Co-Authors: Kerry Gallagher, Roderick Brown, John Stephenson, Christopher Holmes, Paul G FitzgeraldAbstract:Abstract Low-temperature Thermochronology is a powerful method for constraining the time–temperature history of rocks and provides constraints on denudation chronologies, landscape evolution and tectonic history of geological terrains. We present a strategy for modelling thermal histories constrained by thermochronological data from multiple samples in vertical profiles. The thermal history is specified to be similar in form for each sample, and we include extra parameters to determine the offset temperature between the uppermost and lowermost samples. We combine the likelihood from each sample to produce a joint likelihood for all samples together, and using initially stochastic search then directed search methods we try to identify a maximum likelihood solution. We also implement a test (Bayesian Information Criterion) which allows us to assess whether we have overparameterised the thermal history and potentially introduced unwarranted complexity. This test allows us to simplify the thermal history model without compromising the acceptable data fit. Subsequently, we use a sampling approach to determine the uncertainty or resolution of the thermal history. Markov chain Monte Carlo is straightforward to implement and is used to produce joint and marginal probability distributions, and from these we can infer credible intervals on the model parameters. We demonstrate that combining the samples is preferable in that the final model is easier to interpret and generally has smaller uncertainties than the case where we model all samples independently. We consider both synthetic and real data examples, focusing on apatite fission track analysis, but the general approach is applicable to other analytical methods such as (U–Th) / He dating and 40Ar / 39Ar analysis and in principle it is straightforward to combine these different data types into one joint thermal history model.
Andres Mora - One of the best experts on this subject based on the ideXlab platform.
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cenozoic paleogeography of the andean foreland and retroarc hinterland of colombia
AAPG Bulletin, 2015Co-Authors: Andres Reyesharker, Andres Mora, Mauricio Parra, Carlos Fernando Ruizvaldivieso, Juan Carlos Ramirezarias, Guillermo Rodriguez, Felipe De La Parra, Victor Caballero, Nestor Moreno, Brian K HortonAbstract:New biostratigraphic zonations, core descriptions, sandstone petrography, facies analysis, and seismic information are compared with published detrital and bedrock geo- and Thermochronology to build a Cenozoic paleogeographic reconstruction of the Andean retroarc region of Colombia, encompassing the ancestral Central Cordillera, Middle Magdalena Valley, Eastern Cordillera, and Llanos basin. We identify uplifted sediment source areas, provenance domains, depositional environments, and thickness changes to propose a refined paleogeographic evolution of eastern Colombia. We conclude that Cenozoic evolution of the northernmost Andes includes (1) a period of contractional deformation focused in the Central Cordillera and Middle Magdalena Valley that may have started by the Late Cretaceous, although thermochronological data points to maximum shortening and exhumation during the late Paleocene; (2) a period of slower deformation rates or even tectonic quiescence during the middle Eocene; and (3) a renewed phase of contractional deformation from the late Eocene to the Pleistocene/Holocene expressed in provenance, bedrock Thermochronology, and increased subsidence rates in the Llanos foreland. The sedimentary response in the Llanos foreland basin is controlled by source area proximity, exhumation and shortening rates, relationships between accommodation and sediment supply, as well as potential paleoclimate forcing. This new reconstruction changes the picture of Cenozoic basin evolution offered by previous reconstructions, providing an updated chronology of deformation, which is tied to a more precise understanding of basin evolution.
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discriminating rapid exhumation from syndepositional volcanism using detrital zircon double dating implications for the tectonic history of the eastern cordillera colombia
Geological Society of America Bulletin, 2012Co-Authors: Joel E Saylor, Daniel F Stockli, Brian K Horton, Andres MoraAbstract:Lag time is the difference between the closure age of a thermochronologic system and the depositional age of host strata. Lag-time analysis of sedimentary basin fi ll provides insight into the exhumation history of adjacent eroded orogens. In a case study of the Paleogene Floresta basin in the Eastern Cordillera fold-thrust belt of Colombia, variations in lag time refl ect changes in both sediment source areas and exhumation patterns. However, near-zero lag times can be produced by either syndepositional volcanism or rapid exhumation. We applied U-Pb geochronology and (U-Th)/He (ZHe) Thermochronology to individual zircon grains and identifi ed zircons of volcanic origin as those for which the U-Pb age is within the 2σ uncertainty of their ZHe age. Consistent discrimination of young ZHe ages as the products of either rapid exhumation or volcanism reveals three stages in the history of the northern Andean hinterland. (1) Early to late Paleocene: The appearance of syndepositional and Mesozoic volcanic zircons marks the initial infl ux of magmatic arc detritus. (2) Middle to late Eocene: Near-zero lag times point to rapid, regionally extensive exhumation attributable to thrust-induced uplift of the Magdalena Valley basement. (3) Late Eocene to late Oligocene: Increased lag time is interpreted as recycling of shallowly buried foreland-basin strata possibly due to movement on basinbounding thrust systems. The presence of volcanic zircons with ZHe ages younger than or indistinguishable from the youngest exhumationally cooled zircons underscores the need for double dating to reliably identify volcanic infl uence in detrital Thermochronology datasets. These data highlight the utility of double-dated ZHe results for extracting tectonic histories and reliably excluding volcanic zircons from lag-time analysis.
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influences of tectonic inheritance and exhumation patterns in the timing and structural styles of the eastern cordillera of colombia
2005Co-Authors: Andres Mora, Mauricio Parra, Manfred R Strecker, Edward R SobelAbstract:INTRODUCTION The Eastern Cordillera of Colombia is interpreted as an asymmetric inversion orogen, which coincides with the location of a Lower Cretaceous rift province . The degree of asymmetry of i15 central segment is depicted by the basement Iying at a higher elevation on the eastern side than on the western side (Cortes et al., 2005) , and the apparent higher amount of shortening in the eastern flank (Colleta et al., 1990; Dengo&Covey , 1993). Although the role of inherited basement structures can be demonstrated at various scales, the exact role of inversion tectonics in the overall structural styles has remained highly speculative and the causes and consequences of such asymmetry are often ambiguous . Here, we analyze the structural evolution of the Eastern Cordi liera in light of structural inheritance, resulting structural styles, and exhumation patterns using field observations and apatite fission track Thermochronology. Our new data sheds light on the mechanisms responsible for orogenie development in pre-strained regions of the crust.
Massimiliano Zattin - One of the best experts on this subject based on the ideXlab platform.
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cenozoic pulsed deformation history of northeastern tibetan plateau reconstructed from fission track Thermochronology
Tectonophysics, 2016Co-Authors: Xiuxi Wang, Chunhui Song, Massimiliano Zattin, Ai Song, Qiangqiang WangAbstract:Abstract The synorogenic basin deposits and bedrocks of their source terranes within and along the Tibetan Plateau contain fundamental information regarding the spatiotemporal evolution of the largest orogenic plateau on Earth. The Guide–Xining region is located on the northeastern portion of the Tibet and its Eocene–early Pleistocene basin succession is well preserved. By integrating apatite fission-track Thermochronology from sedimentary and basement samples, with heavy minerals and paleocurrent data, we decipher an almost complete sequence of exhumation and depositional events during the Cenozoic. Our data indicates that the initial deformation along the Guide–Xining region occurred since the Eocene, with the reorganization of the regional tectonomorphology and the formation of a broad basin. Thereafter, this single large basin was disrupted by multiple episodes of exhumation and deformation. Our study illuminate that the multiple-stage active processes (occurred at 49–42, 36–32, 23–19, 16–13 and 8–4 Ma) work together to produce the current NE Tibetan Plateau.
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exhuming the alps through time clues from detrital zircon fission track Thermochronology
Basin Research, 2009Co-Authors: Matthias Bernet, Mark T. Brandon, John I Garver, Ml Balestieri, B Ventura, Massimiliano ZattinAbstract:The European Alps are a mountain belt that is characterized by a series of discrete orogenic events, which have long been recognized. Despite the inherent episodic nature of orogenic evolution, the Alps have been continuously exhumed, mainly by erosion, but also by normal faulting. Since continental collision started in the late Eocene/Early Oligocene evidence for ongoing erosional exhumation has been preserved in synorogenic sediments that accumulated in basins adjacent to the pro - and retro - side of this double-vergent mountain belt.This long-term erosion record can be used to determine exhumation rates. Lag-times calculated from ¢ssion-track (FT) ages of detrital zircon from synorogenic sediments are fairly constant for the European Alps since the Oligocene^Late Miocene. Although the fast exhuming areas were unroofed at rates of 0.4^0.7 km Myr � 1 , the overall average exhumation rate is between 0.2 and 0.3 km Myr � 1 on a regional scale.The detrital and bedrock zircon FT data of the Alps do not detect the increase in erosion rates since the Pliocene over the past � 5 Myr, as shown elsewhere.This increase cannot be detected yet with the detrital zircon FT method because not enough rock has been removed to widely expose zircons with Pliocene or younger cooling ages in the Alps. Long term (30 Myr) exhumation rates appear to have been approximately constant when averaged over a sliding time window of about 8 Myr, or depth window of 5 to 10 km (ZFT closure depths); shorter-term £uctuations are not identi¢ed using this method.