Application of Thermochronology to Geologic Problems: Bedrock and Detrital Approaches

Malusà, Marco G.; Fitzgerald, Paul G.

doi:10.1007/978-3-319-89421-8_10

Cited by 31 publications

(33 citation statements)

References 119 publications

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“…In the western Dongdatan Valley, thermochronologic ages from a Triassic gneiss collected within 1 km of the Xidatan fault yield ~19 Ma cooling ages from both apatite (U‐Th)/He and fission track methods (Figure 2a). According to experimental and field studies of transpressional environments, exhumation due to strike‐slip faulting is commonly of high magnitude and highly localized near the fault trace (Malusà & Fitzgerald, 2019; Niemi et al, 2013; Spotila et al, 2001; Wilcox et al, 1973). Thermal modeling of our data indicates rapid cooling between 20.0°C Myr −1 and 21.6°C Myr −1 in the interval between 23 and 17 Ma (Figure 6a).…”

Section: Discussionmentioning

confidence: 99%

The Cenozoic Evolution of Crustal Shortening and Left‐Lateral Shear in the Central East Kunlun Shan: Implications for the Uplift History of the Tibetan Plateau

et al. 2020

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The timing of crustal shortening and strike-slip faulting along the East Kunlun Shan provides insight into the history of surface uplift and may constrain the time at which the Tibetan Plateau reached high elevations. We investigate a series of extensional basins and restraining bends along the Xidatan strand of the Kunlun strike-slip fault, which provide an ideal setting to unravel the tectonic history of the northern plateau margin. We present new apatite (U-Th)/He, apatite fission track, and zircon (U-Th)/He ages and QTQt thermal modeling, 40 Ar/ 39 Ar fault gouge dating, and structural mapping from the central East Kunlun Shan. Our data suggest that the East Kunlun Shan experienced slow to negligible exhumation until late Cretaceous time, followed by an increase in rate by 65-50 Ma. Along with a~47 Ma fault gouge age, we posit that the Paleocene-early Eocene was a time of crustal shortening along the northern plateau. Rapid exhumation along transpressional portions of the Xidatan fault initiated by 23-20 Ma, which we interpret as the local onset of strike-slip faulting. An early Miocene transition from north-south crustal shortening to left-lateral shear along the East Kunlun Shan, the onset of normal and strike-slip faulting in central and southern Tibet by 18 Ma, and lower crustal flow in eastern Tibet by 13 Ma suggest the establishment of orogen-wide east-west oriented extension and extrusion by the middle Miocene. The plateau-wide shift in stress accommodation implies that high gravitational potential energy, and likely high elevation, was attained by the middle Miocene.

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Section: Discussionmentioning

confidence: 99%

The Cenozoic Evolution of Crustal Shortening and Left‐Lateral Shear in the Central East Kunlun Shan: Implications for the Uplift History of the Tibetan Plateau

et al. 2020

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“…3a will determine different and diagnostic thermochronologic fingerprints in bedrock and detritus (see Section 3). Strategies exist to discriminate among different scenarios and minimize the risk of misinterpretations (see discussion in Malusà and Fitzgerald, 2019b). For example, approaches include multiple dating of detrital mineral grains using different thermochronologic systems (see review in Danišík, 2019) in order to identify mineral grains crystallized above the Tc isotherm (Carter and Moss, 1999;Saylor et al, 2012;Bernet et al, 2019).…”

Section: Assumption 1: Ages Reflect Cooling Through Closure Temperature Tc During Exhumationmentioning

confidence: 99%

The geologic interpretation of the detrital thermochronology record within a stratigraphic framework, with examples from the European Alps, Taiwan and the Himalayas

Malusà

Fitzgerald

2020

Earth-Science Reviews

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Detrital thermochronology studies based on the lag-time approach are increasingly employed to investigate the erosional evolution of mountain belts and perform paleotectonic reconstructions starting from the analysis of sedimentary rocks. However, simple predictions of lag-time conceptual models are often in conflict with observations in sedimentary basins. In this review article, we discuss the major assumptions of the lag-time approach, and present conceptual models to illustrate the main factors that may influence the final complexity of the detrital thermochronologic record in a sedimentary basin. These factors include: (i) the original complexity of the thermochronologic age structure in the source region; (ii) mixing of detritus from multiple source regions characterized by different geologic evolution; (iii) modifications of the original thermochronologic fingerprint from source to sink; (iv) potential post-depositional annealing due to thick sedimentary burial. Based on this synthesis and discussion, we present a list of interpretive guidelines and fundamental criteria for the geologic interpretation of the detrital thermochronologic record derived from the erosion of single and mixed sources. These interpretive guidelines are then applied to published detrital thermochronology datasets from the European Alps, Taiwan and the Himalayas in order to illustrate benefits and pitfalls of the geologic interpretation of thermochronologic age trends through a stratigraphic succession. Results provide evidence for (i) non-steady-state exhumation of the European Alps, (ii) late Miocene onset of arc-continent collision in Taiwan, and (iii) late Miocene morphogenic phase of mountain building in the Himalaya. Concepts presented in this article reinforce existing approaches and provide new perspectives for the application of the detrital thermochronologic approach to tectonic settings where the geologic evolution may be poorly understood. As such, they are expected to guide geologists towards interpretations that are both consistent with evidence provided by different thermochronologic systems, and geologic evidence provided by the rock record.

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“…Also, determining an average exhumation rate assumes that the source rock is cooled/exhumed within one orogenic cycle. For modern river detritus, with a stratigraphic age of "zero," the youngest age mode can be used to constrain the average exhumation rate of the source area (e.g., Malusà & Fitzgerald, 2019b). For example, a sample with a polymodal grain-age distribution can typically be deconvolved into different grain-age subgroups; the defined mode 10.1029/2019TC005764 Tectonics for the youngest age component (t 1 ) is then assumed as the cooling age (if the area was rapidly exhumed), and the depositional age, t 0 , of the sample is zero.…”

Section: Methodsmentioning

confidence: 99%

Detrital Thermochronology Reveals Major Middle Miocene Exhumation of the Eastern Flank ofthe Andes That Predates the PampeanFlat Slab (33°–33.5°S)

et al. 2020

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The Cordón del Plata and Cordón del Portillo (32.6°-33.8°S) are the portions of the Frontal Cordillera that straddle the transition zone between the Pampean flat-slab subduction segment to the north and the normal subduction segment to the south. A complete understanding of how the Frontal Cordillera developed is necessary in order to evaluate different tectonic models for the Andes along with their relation to subduction dynamics and contractional upper-crustal deformation. Detrital apatite fission track thermochronology of modern river sediments that drain the eastern and western slopes of the Cordón del Plata and the northern Cordón del Portillo provides constraints on regional exhumation histories. AFT data from each catchment typically contain multiple age peaks, but all have a prominent 15.3-17 Ma age peak. One catchment, the Las Tunas River has a unimodal distribution at 17.0 ± 1.1 Ma, with a confined track length distribution indicative of rapid cooling at that time. These results, combined with provenance analysis in the adjacent Cacheuta Basin, indicate significant early to middle Miocene (~16 Ma) exhumation in the Cordón del Plata and the northern sector of the Cordón del Portillo. Exhumation related to rock uplift occurred prior to the~11 Ma onset of a flat slab geometry at these latitudes, but immediately after the main east vergent contractional event in the adjacent Principal Cordillera. Such Frontal Cordillera exhumation fits in an eastward, youngest to the foreland sequence of deformation of the different morphostructural Andean units at~33°-34°S, arguing against the recently proposed west vergent orogenic system at these latitudes.

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Application of Thermochronology to Geologic Problems: Bedrock and Detrital Approaches

Cited by 31 publications

References 119 publications

The Cenozoic Evolution of Crustal Shortening and Left‐Lateral Shear in the Central East Kunlun Shan: Implications for the Uplift History of the Tibetan Plateau

The Cenozoic Evolution of Crustal Shortening and Left‐Lateral Shear in the Central East Kunlun Shan: Implications for the Uplift History of the Tibetan Plateau

The geologic interpretation of the detrital thermochronology record within a stratigraphic framework, with examples from the European Alps, Taiwan and the Himalayas

Detrital Thermochronology Reveals Major Middle Miocene Exhumation of the Eastern Flank ofthe Andes That Predates the PampeanFlat Slab (33°–33.5°S)

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