Chapter 33 Heavy Minerals and Detrital Fission-Track Thermochronology
Introduction
Sedimentary provenance studies rely on diagnostic minerals to determine where component grains have come from in terms of their source lithology. Taking into account any affects from weathering, change in detrital mineralogy reflects either exhumation of rock from progressively deeper levels within the crust or changes in the sediment routing system. To help explain such changes, detrital thermochronometry can be used to provide a more quantitative description of the source terrain in terms of age structure, composition and timing and rates of uplift and exhumation. Detrital thermochronometry is based on extracting records of isotopic decay from parent atoms contained within single detrital grains using mass spectrometry (40Ar-39Ar, U-Pb, Rb/Sr), ion probe (U-Pb) or neutron activation techniques (fission-track, FT). Advances in technology (principally laser ablation mass spectrometry: LA-ICP-MS) have increased analytical sensitivity and precision to levels that permit routine detailed investigation of grain age and compositional structure providing larger, statistically more robust datasets and thus an improved image of sediment source. Commonly used thermochronometric methods include zircon U-Pb dating (Gehrels et al., 1995; Carter and Bristow, 2000), FT analysis (Cerveny et al., 1988; Hurford and Carter, 1991; Carter, 1999; Garver et al., 1999) and more recently detrital mica argon dating (Von Eynatten et al., 1996; Sherlock et al., 2002; Hodges et al., 2005). Zircon U-Pb dating records crystal formation and growth history due to isotopic closure at high temperatures, typically >700 °C, which is ideal for identifying formation age of source terrain lithologies (e.g., DeCelles et al., 2004), provided the dated zircon has not been through crustal recycling events as is often the case in orogens. With recycling the durability of zircon and resistance of the U-Pb system to thermal, resetting can result in detrital zircon U-Pb ages unconnected to the immediate source terrain. Although knowledge about hinterland rock formation age is useful for identifying where sediment may have come from, it provides little insight into the geodynamic development of a source region and the processes driving erosion and producing stratigraphic changes in heavy minerals. Constraints on erosion processes can be retrieved using detrital zircon and apatite FT analysis, a low temperature method that records cooling history from ∼300 °C down to ∼50 °C, temperatures that correspond to parts of the upper crust most sensitive to earth surface/climate/tectonic interactions. This chapter examines the role of detrital FT analysis in heavy mineral and provenance studies and considers how it can be best used to understand source evolution and trends in sediment composition and accumulation.
Section snippets
Principles of FT Analysis
FT thermochronometry, based on uranium decay, is dependant on data obtained from single grains (Fig. 1) and is therefore ideally suited to provenance studies. It was first used as a provenance tool by Gleadow and Lovering (1974) and a succession of provenance-related FT studies have since followed (see reviews by Hurford and Carter, 1991; Carter, 1999; Garver et al., 1999; Bernet and Garver, 2005). FT analysis is based on quantifying the amount of natural decay of uranium (238U) by spontaneous
Understanding the Significance of Detrital FT Ages
Providing that detrital apatite or zircon FT ages have not been reset by heating, resulting from post-depositional burial, measured ages will relate either to the formation age of a source lithology or its exhumation history defined as movement of rock towards the surface (Fig. 2). Apatites are more sensitive than zircon to resetting since post-depositional burial to temperatures >80–100 °C will degrade or reset an apatite's FT provenance record, the precise temperature depending on grain
Combined Heavy Mineral: Detrital FT Studies
FT analysis has a relatively long record of use in provenance studies (Hurford and Carter, 1991; Carter, 1999; Garver et al., 1999, and references therein), principally because it was one of the first mineral dating techniques based on data extracted from single grains. A wide range of FT provenance applications can be found in the literature, covering topics as diverse as dating stone tools and fossil beds to detect movements of Homo erectus (Moorwood et al., 1998), to constrain when India and
Integrating Mineral Geochemistry with Thermochronometry
Use of heavy mineral assemblages to track changes in source or hinterland exhumation and thermochronometric data to record timing and rates of exhumation provide an image of the sediment source with a resolution that largely depends on the size of a given drainage system. In the case of large orogens such as the ∼2000 km Himalayan arc, a single sample collected from either the Bengal or Indus fan is unlikely to be diagnostic of a discrete part of the orogen due to the effects of mixing during
Conclusions
Detrital FT analysis remains an essential tool in provenance research, especially for studies that seek to use the sediment record to reconstruct source exhumation history. Robust interpretation of detrital thermochronometric data requires understanding the composition of the source terrain in terms of its formation, age, structure and component tectonostratigraphic units, as obtained from complementary heavy mineral data. Although the heavy mineral community have long recognised the benefit of
Acknowledgements
The author thanks Tony Hurford and Mathias Bernet for their careful reviews and helpful suggestions.
References (56)
- et al.
Compositional and structural control of fission-track annealing in apatite
Chemical Geology
(2003) Present status and future avenues of source region discrimination and characterisation using fission track analysis
Sedimentary Geology
(1999)- et al.
Detrital geochronology and geochemistry of Cretaceous—early Miocene strata of Nepal: implications for timing and diachroneity of initial Himalayan orogenesis
Earth and Planetary Science Letters
(2004) The radial plot: graphical assessment of spread in ages
Nuclear Tracks and Radiation Measurement
(1990)- et al.
Estimating the component ages in a finite mixture
Nuclear Tracks and Radiation Measurement
(1990) Evolving temperature histories from apatite FT data
Earth and Planetary Science Letters
(1995)- et al.
Sand petrology and focused erosion in collision orogens: the Brahmaputra case
Earth and Planetary Science Letters
(2004) - et al.
The effect of weathering on FT dating
Earth and Planetary Science Letters
(1974) - et al.
Statistical modelling of FTs in apatite
Geochimica Cosmochimica Acta
(1996) - et al.
Thermal annealing of fission tracks in apatite 2. A quantitative analysis
Chemical Geology (Isotope Geoscience Section v.)
(1987)
Impact of safe water for drinking on five families for 2 years in West Bengal, India
Science of the Total Environment
Himalayan architecture constrained by isotopic tracers from clastic sediments
Earth and Planetary Science Letters
Mixture modelling of multi-component data sets with application to ion-probe zircon ages
Earth and Planetary Science Letters
A review of the source, behaviour and distribution of arsenic in natural waters
Applied Geochemistry
How many grains are needed for a provenance study? Earth and Planetary Science Letters
Annealing kinetics of FTs in zircon: an experimental study
Chemical Geology (Isotope Geoscience Section)
Arsenic toxicity of groundwater in parts of the Bengal basin in India and Bangladesh: the role of Quaternary stratigraphy and Holocene sea-level fluctuations
Environmental Geology
Carbonate ions and arsenic dissolution by groundwater
Environmental Science and Technology
Fission-track analysis of detrital zircon
Reviews in Mineralogy and Geochemistry
Steady-state exhumation of the European Alps
Geology
Decomposition of fission track grain age distributions
American Journal of Science
New Statistical methods for analysis of FT grain age distributions with applications to detrital zircon ages from the Olympic subduction complex, western Washington State
American Journal of Science
Variability of apatite fission-track annealing experiments: I. Experimental results
American Mineralogist
Episodic exhumation in the Western Alps
Geology
Detrital zircon geochronology: enhancing the quality of sedimentary source information through improved methodology and combined U-Pb and fission track techniques
Basin Research
Combined detrital-zircon fission-track and U-Pb dating: a new approach to understanding hinterland evolution
Geology
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