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(For further information on spectroscopy, see:
http://speclab.cr.usgs.gov)
TITLE: WTC_Dust_Debris WTC01-28 DESCRIPT
DOCUMENTATION_FORMAT: Man_Made
SAMPLE_ID: WTC01-28
MATERIAL_TYPE: Dust and Debris
MATERIAL: Dust and Debris
FORMULA: None
FORMULA_HTML: None
COLLECTION_LOCALITY: Lower Manhattan Island, New York, USA
ORIGINAL_DONOR: Gregg Swayze and Todd Hoefen
CURRENT_SAMPLE_LOCATION: U.S. Geological Survey, Denver, Colorado
ULTIMATE_SAMPLE_LOCATION: U.S. Geological Survey, Denver, Colorado
SAMPLE_DESCRIPTION:
This dust sample was collected Sept. 18, 2001 from the sidewalk at the intersection of Ann and Nassau Streets about 0.4 km east of the WTC site on Manhattan Island, New York. Sample consists of fine-grained grayish white dust believed to be from the dust cloud generated when the World Trade Center Towers collapsed on Sept. 11, 2001. The sample was probably exposed to rain on the evening of Sept. 14. A location map and details of the sample collection process are given in Roger N. Clark and others, Environmental Studies of the World Trade Center area after the September 11, 2001 attack, U.S. Geological Survey Open File Report OFR-01-0429. This report is available at http://pubs.usgs.gov/of/2001/ofr-01-0429/
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
calcite (minor), gypsum (minor), quartz (minor), and anhydrite (minor). In general minor = 5 - 20 wt%, trace > 5 wt%.
see: Roger N. Clark and others, Environmental Studies of the World Trade Center area after the September 11, 2001 attack, U.S. Geological Survey Open File Report OFR-01-0429. This report is available at http://pubs.usgs.gov/of/2001/ofr-01-0429/
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EM(WDS), ICP(Trace), WChem
COMPOSITION_TRACE: None
COMPOSITION_DISCUSSION:
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
END_MICROSCOPIC_EXAMINATION.
SPECTROSCOPIC_DISCUSSION:
There are only weak spectral absorptions, apart from the absorption edge, in the electronic region of the spectra (0.35 - 1.35 microns) indicating that the dust contains only low abundances of materials with Fe absorptions or absorptions from other transition elements. However, there are numerous spectral absorptions in the vibrational spectral region from 1.35 - 2.5 microns principally at 1.45, 1.75, 1.94, 1.97,and from 2.2 - 2.4 microns. The strongest spectral feature is at 1.94 microns and is due to structural and adsorbed water, with the next weaker feature at 1.45 microns (due to water and/or OH). Spectral features at 1.75 microns are next weakest with depths of only a few %. Spectral features in the 2 micron region are weakest.
Gypsum, probably from crushed wallboard, has the strongest spectral features accounting for most of the bands observed in the vibrational portion of the spectra. This mineral has three diagnostic bands that form a stair-step like triplet between 1.42 - 1.54 microns recognizable in nearly all dust samples. It also has bands at 1.75, 1.95, 1.975, 2.17, 2.217, and 2.268 microns closely matching the positions and geometry of the bands observed in the dust. In addition to those absorptions attributable to gypsum, an absorption at 1.413 microns may be due to portlandite or muscovite, both mineral components of the WTC concrete. Additional absorptions located at 2.307 and 2.343 microns are due to C-H stretches from organic materials.
No chrysotile asbestos was detected in this sample above the 1 wt% lower detection threshold by XRD or spectroscopy.
END_SPECTROSCOPIC_DISCUSSION.
SPECTRAL_PURITY: 1a2_3_4_ # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
| LIB_SPECTRA_HED: | where | Wave Range | Av_Rs_Pwr | Comment |
|---|---|---|---|---|
| LIB_SPECTRA: | splib05a r 10636 | 0.2-3.0µm | 200 | g.s.= |
| LIB_SPECTRA: | splib06a r 29548 | g.s.= |