X-ray diffraction data from Silurian conodonts belonging to various developmental stages of the species Dapsilodus obliquicostatus demonstrate changes in crystallography and degree of nanocrystallite ordering (mosaicity) in both hyaline and albid crown tissue. The exclusive use of a single species in this study, combined with systematic testing of each element type at multiple locations, provided insight into microstructural and crystallographic differentiation between element position (S_a, S_b-c, M) as well as between juveniles and adults. A relative increase in the unit cell dimensions of the a-axis/c-axis ratio of nanocrystallites during growth was apparent in areas demonstrating single-crystal behavior but no such relationship was seen in dominantly polycrystalline areas. Systematic variations in mosaicity were identified, with mosaicity (as a proxy for disorder) increasing during growth, as well as along elements from tip to base. These results provide potential insight into the integrity of conodont apatite as a recorder of paleoseawater chemistry, as well as demonstrate the need to consider the influence of ontogeny and element position on the use of conodonts in paleothermometry and geochemical investigations.    

X-ray diffraction experiments were carried out in a Bruker D8 Quest single crystal X-ray diffractometer equipped with a CMOS area detector that allows diffraction pattern analysis of both single-crystalline and polycrystalline material. Irradiation of samples occurred through a microfocus Mo Kα (λ = 0.7107 Å) X-ray source with a beam diameter of 120 μm, which is suitable to analyze multiple positions along each specimen. Depending on the size of the sample, three to six zones were analyzed along the length of each element. In a typical experiment, conodont elements were coated with mineral oil, then attached on top of MiTeGen Dual-Thickness MicroLoop in a vertical position.  The sample was placed on the three-circle goniometer and the position of the X-ray beam was chosen using the microscope camera. X-ray diffraction data associated with each position were collected in reflection mode by varying the Φ angle while keeping the other angles fixed (2θ=0^o, ω=0^o and χ=54.74^ᵒ). An eight- to eleven-second exposure time was needed for analyzing albid and hyaline material and a 20-30 second exposure time was needed for the basal cavity. Alignment of the diffractrometer was calibrated using the standard YLID crystal provided by Bruker AXS.

This DATSETNAMEreadme.txt file was generated on 2020-06-30 by Mohammad Shohel

GENERAL INFORMATION

1. Title of Dataset: Ontogenetic variability in crystallography and mosaicity of conodont apatite: Implications for microstructure, paleothermometry and geochemistry

2. Author Information
    A. Principal Investigator Contact Information
        Name: Tori Z. Forbes
        Institution: University of Iowa
        Address: Department of Chemistry, University of Iowa, Iowa City, IA 52242, USA
        Email: tori-forbes@uiowa.edu

    B. Associate or Co-investigator Contact Information
        Name: Bradley D. Cramer
        Institution: University of Iowa
        Address: Department of Earth and Environmental Sciences, University of Iowa, Iowa City, IA 52242, USA
        Email: bradley-cramer@uiowa.edu

    C. Alternate Contact Information
        Name: 
        Institution: 
        Address: 
        Email: 

3. Date of data collection (single date, range, approximate date) : 2016-2018

4. Geographic location of data collection : Department of Chemistry, University of Iowa, Iowa City, IA 52242, USA

5. Information about funding sources that supported the collection of the data: American Chemical Society- Petroleum Research Fund (ACS-PRF) Grant # ND-18485100

SHARING/ACCESS INFORMATION

1. Licenses/restrictions placed on the data: 

2. Links to publications that cite or use the data: 

Shohel M, McAdams NEB,
Cramer BD, Forbes TZ. 2020 Ontogenetic variability
in crystallography and mosaicity of conodont
apatite: implications for microstructure,
palaeothermometry and geochemistry. R. Soc. Open
Sci. 7: 200322.
http://dx.doi.org/10.1098/rsos.200322

3. Links to other publicly accessible locations of the data: 

4. Links/relationships to ancillary data sets: 

5. Was data derived from another source? yes/no
    A. If yes, list source(s): 

6. Recommended citation for this dataset: 

Shohel M, McAdams NEB,
Cramer BD, Forbes TZ. 2020 Ontogenetic variability
in crystallography and mosaicity of conodont
apatite: implications for microstructure,
palaeothermometry and geochemistry. R. Soc. Open
Sci. 7: 200322.
http://dx.doi.org/10.1098/rsos.200322

DATA & FILE OVERVIEW

1. File List: 
Sa-1, Sa-2, Sa-3, Sa-4, Sa-5: Folders that conatain diffrcation frames of 5 Sa elements of conodont microfossils. Inside those folder there are subfolder with end "T" and a "number" (e.g. T1). The number indicates specific zone that was anlysed. and the subfolder contain diffraction frames of that zone.
Sbc-1, Sbc-2, Sbc-3, Sbc-4, Sbc-5: Folders that conatain X-ray diffrcation frames of 5 Sbc elements of conodont microfossils. Inside those folder there are subfolder with end "T" and a "number" (e.g. T1). The number indicates specific zone that was anlysed. and the subfolder contain diffraction frames of that zone.
M-1, M-2, M-3, M-4: Folders that conatain X-ray diffrcation frames of 5 Sa elements of conodont microfossils. Inside those folder there are subfolder with end "T" and a "number" (e.g. T1). The number indicates specific zone that was anlysed. and the subfolder contain diffraction frames of that zone.
Basal split: Folder contains X-ray diffraction frames of split basal body. 

2. Relationship between files, if important: 

3. Additional related data collected that was not included in the current data package: 

4. Are there multiple versions of the dataset? yes/no
    A. If yes, name of file(s) that was updated: 
        i. Why was the file updated? 
        ii. When was the file updated? 

METHODOLOGICAL INFORMATION

1. Description of methods used for collection/generation of data: 
X-ray diffraction experiments were carried out in a Bruker D8 Quest single crystal X-ray diffractometer equipped with a CMOS area detector that allows diffraction pattern analysis of both single-crystalline and polycrystalline material. Irradiation of samples occurred through a microfocus Mo Kα (λ = 0.7107 Å) X-ray source with a beam diameter of 120 μm, which is suitable to analyze multiple positions along each specimen. Depending on the size of the sample, three to six zones were analyzed along the length of each element. In a typical experiment, conodont elements were coated with mineral oil, then attached on top of MiTeGen Dual-Thickness MicroLoop in a vertical position.  The sample was placed on the three-circle goniometer and the position of the X-ray beam was chosen using the microscope camera. X-ray diffraction data associated with each position were collected in reflection mode by varying the Φ angle while keeping the other angles fixed (2θ=0o, ω=0o and χ=54.74ᵒ). An eight- to eleven-second exposure time was needed for analyzing albid and hyaline material and a 20-30 second exposure time was needed for the basal cavity. Alignment of the diffractrometer was calibrated using the standard YLID crystal provided by Bruker AXS.

2. Methods for processing the data: 
The submitted data is in sfrm format which in standard for single crystal diffraction frames. 

3. Instrument- or software-specific information needed to interpret the data: 
Any single crystal X-ray diffraction data processing software that are capable of reading sfrm file can be used to interpret the data. We used APEX-3 software provided by Bruker AXS, USA. 

4. Standards and calibration information, if appropriate: When analyzing Debye ring, the detector distance, swing angle, and beam center were calibrated by comparing the 2θ angles and detector position of a polycrystalline biomimetic
fluorapatite standard produced in the University of Iowa Department of Chemistry

5. Environmental/experimental conditions: The diffraction experiment was carried out at 100K. 

6. Describe any quality-assurance procedures performed on the data: Alignment of the diffractrometer was calibrated using the standard YLID crystal provided by Bruker AXS.