ARC Centre of Excellence for Core to Crust Fluid Systems

Dr Dan Howell

MSci, PhD London.

Credentials

MSci (Hons) Geoscience, Royal Holloway, University of London, UK, 2004; PhD, University College London, UK, 2009

Research Interests and Past Work

My research interests are focused upon the study of diamonds and their inclusions. My PhD was based around the use of birefringence (which is a stress related optical property in diamond) to investigate the history of diamonds. This work covered the full range of using quantitative birefringence analysis, starting with experimentally re-evaluating the photoelastic constants of diamond, using the MetriPol birefringence analysis system. After that, my work focused on using the strain birefringence halos commonly observed around inclusions to measure the remnant pressure the inclusions are under, and from that calculate possible source conditions in the mantle. As plastic deformation is another common cause of birefringence in diamond, and it is inherently linked to the development of brown colour, I undertook a HPHT experimental investigation into the deformation of diamond under mantle conditions.

Current Research Projects

I am currently working on the ARC Discovery Project, “Diamond genesis: cracking the code for deep-Earth processes” with Sue O’Reilly, Bill Griffin & Norm Pearson. This project will involve utilizing the various optical analytical techniques applicable to diamond (FTIR, Raman, CL, XPL) in combination with geochemical analytical techniques (LA-ICP-MS, SIMS) to further investigate the physical and geochemical conditions that diamonds and their inclusions form in and are subjected to during their lifetime.

Publications

(see http://publicationslist.org/daniel.howell)

11) Howell, Griffin, Pearson, Powell, Wieland, O‘Reilly, 2013. Trace element partitioning between growth sectors in mixed-habit diamonds. Chemical Geology, 355, 134-143. [IF: 3.518]

10) Howell, Griffin, Piazolo, Say, Stern, Stachel, Nasdala, Rabeau, Pearson & O’Reilly, 2013. A spectroscopic and carbon-isotope study of mixed-habit diamonds: Impurity characteristics and growth environment. American Mineralogist, 98, 66-77. [IF: 1.86, citations: 2]

9) Howell, Piazolo, Dobson, Wood, Jones, Walte, Frost, Fisher & Griffin, 2012. Quantitative characterization of plastic deformation of single diamond crystals: a High Pressure High Temperature (HPHT) experimental deformation study combined with Electron Backscatter Diffraction (EBSD). Diamond and Related Materials, 30, 20-30. [IF: 1.913, citations: 0]

8) Howell, O’Neill, Grant, Griffin, Pearson, O’Reilly, Stern, Stachel, 2012. Platelet development in cuboid diamonds: insights from µ-FTIR mapping. Contributions to Mineralogy & Petrology, 164, 1011-1025. [IF: 3.441, citations: 3]

7) Howell, O’Neill, Grant, Griffin, Pearson & O’Reilly, 2012. µ-FTIR mapping: Distribution of impurities in different types of diamond growth. Diamond and Related Materials, 29, 29-36. [IF: 1.913, citations: 5]

6) Howell, 2012. Strain induced birefringence in natural diamond: a review. European Journal of Mineralogy, 24(4), 575-585. [IF: 1.486, citations: 2]

5) Howell, Wood, Nestola, Nimis & Nasdala, 2012. Inclusions under remnant pressure in diamond: A multi-technique approach. European Journal of Mineralogy, 24(4), 563-573. [IF: 1.486, citations: 2]

4) Tomlinson, Howell, Jones & Frost, 2011. Characteristics of HPHT diamond grown at sub-lithospheric conditions (10-20 GPa). Diamond & Related Materials, 20, 11-17. [IF: 1.913, citations: 2]

3) Howell, Wood, Dobson, Jones, Nasdala & Harris, 2010. Quantifying strain birefringence halos around inclusions in diamond. Contributions to Mineralogy & Petrology, 160, 705-717. [IF: 3.441, citations: 6]

2) Howell & Nasdala, 2008. Using strain birefringence in diamond to estimate the remnant pressure on an inclusion. Australian Journal of Earth Sciences, 55, 1175-1178. [IF: 1.417, citations: 5]

1) Howie, Brewer, Howell & Jones, 2008. Physical basis of colors seen in Congo red-stained amyloid in polarized light. Laboratory Investigations, 88, 232-242. [IF: 3.641, citations: 32]

Recent Conference Abstracts & Invited Talks (over 20 in total)

Howell et al., 2013. Nitrogen isotope systematics and origins of mixed-habit diamonds. Goldschmidt 2013, Florence – poster.

Convenor of a session on mantle research via the study of diamonds and xenoliths at Goldschmidt 2013 (Florence, Italy) with Gareth Davies, Fabrizio Nestola, Lucy Hunt & Maya Kopylova.

Howell et al., 2013. Understanding diamond morphology. Chinese Academy of Geological Sciences, Beijing – invited seminar.

Howell et al., 2012. Trace element partitioning in mixed-habit diamonds. Presented at Goldschmidt (Montreal, Canada), the UK Diamond Conference (Warwick), and the International Geological Congress (Brisbane, Australia) – poster.

Howell, 2011. Spectroscopic tools for studying diamonds. International Short Course for the study of Diamonds in Bressanone (Italy) – Invited lecture.

Howell et al., 2011. Mixed-habit diamonds: Evidence of a specific mantle fluid chemistry? Goldschmidt (Prague, Czech Republic) – talk.

Howell et al., 2010. Imaging diamond: using birefringence and infrared to map strain and impurities. International Mineralogical Association conference, Budapest – Invited talk.

Howell et al., 2010. “Maltese-cross” diamonds: new insights from mixed-habit diamonds. International Mineralogical Association conference, Budapest – talk.

Howell et al., 2010. Optical mapping of diamond. Department of Earth Sciences, Macquarie University – departmental seminar.

Howell et al., 2009. Understanding birefringence in diamond. Institute of Earth Sciences, Hebrew University of Jerusalem – departmental seminar.

Howell et al., 2009. Investigating the history of diamond using birefringence analysis. Institute of Mineralogy and Crystallography, University of Vienna – departmental seminar.

[Back to top]