Facilities at the Ronald B. Gilmore XRF Lab

What we have:

Within the X-ray analytical facility we have three fully-automated X-ray spectrometers.

Routine, high-quality major element analyses (Si, Ti, Al, Fe, Mn, Mg, Ca, Na, K, P) are obtained on fused La-bearing lithium borate glass disks using a Siemens MRS-400 multi-channel, simultaneous X-ray spectrometer. The analytical methods are modified from those of Norrish and Hutton (1969).

Trace element data (Nb, Zr, Y, Sr, Rb, Th, Pb, Ga, Zn, Ni, Cr, V, Ba, Ce, La) are obtained using pressed powder pellets on a recently acquired Philips PW2400 sequential spectrometer. Intensities are corrected for non-linear background, inter-element interferences and variations in mass absorption coefficients, using methods modified from those of Norrish and Chappel (1967). Mass absorption coefficients for elements with shorter characteristic wavelengths than the Fe-absorption edge are estimated from the intensity of the Compton radiation of the Rh X-ray tube (Reynolds, 1967). Mass absorption coefficients of elements with longer characteristic radiation than the Fe-absorption edge are calculated from the Compton-derived mass absorption coefficients, after allowance is made for Fe and Ti intensities (Walker, 1973).

Supporting facilites include rock cutting, crushing and grinding equipment (diamond saws and corer, Spex shatterbox with an assortment of tungsten carbide and steel grinding vessels, boron carbide pestle and mortar), and complete laboratory facilities for sample preparation.

To see some pictures of the lab, click here

What we do:

The analytical methods mentioned above have been used extensively for the analyses of lunar rocks, meteorites, and a wide range of terrestrial materials. These include basalts, granites, metamorphic rocks, soils, and even such weird things as corgaspinites (corundum-garnet-spinel rocks), nelsonites (apatite-magnetite rocks), dinosaur bones and coprolites!

The accompanying table provides an estimate of the accuracy and precision of these methods, based on data for the USGS basalt standard BHVO-1 and multiple analyses of Hawaii Scientific Drilling Project standard KIL-1919, collected by H. West from the same 1919 Kilauea flow as BHVO-1.

Data for USGS standard BHVO-1 and the HSDP standard Kil-1919
	BHVO-1	HSDP Split1	HSDP Split 2	HSDP Split 3	HSDP Split 4	HSDP Split 5	HSDP Split 6	HSDP Average	HSDP S.D.
SiO2	49.58	49.72	49.70	49.91	49.91	49.81	49.70	49.81	0.090
TiO2	2.740	2.767	2.756	2.770	2.761	2.761	2.756	2.763	0.005
Al2O3	13.61	13.68	13.72	13.75	13.76	13.73	13.69	13.73	0.028
Fe2O3	12.17	12.11	12.09	12.09	12.16	12.06	12.07	12.10	0.028
MnO	0.17	0.17	0.17	0.17	0.17	0.17	0.17	0.17	0.001
MgO	7.09	6.95	6.91	6.91	6.93	6.94	6.90	6.93	0.016
CaO	11.35	11.39	11.30	11.40	11.41	11.42	11.38	11.40	0.012
Na2O	2.40	2.49	2.54	2.49	2.49	2.47	2.55	2.50	0.023
K2O	0.522	0.527	0.527	0.530	0.529	0.525	0.527	0.528	0.002
P2O5	0.272	0.275	0.272	0.279	0.273	0.270	0.274	0.274	0.003
Total	99.90	100.08	100.08	100.30	100.39	100.16	100.02	100.20
Mg#	0.562	0.558	0.557	0.557	0.556	0.559	0.557	0.558
Rb	9.2	9.0	8.9	9.2	9.2	8.8	-	9.0	0.16
Sr	388	397	398	397	398	401	-	398.2	1.33
Nb	19.4	19.6	19.4	19.1	19.9	19.5	-	19.5	0.26
Zr	191	187	187	186	188	185	-	186.8	1.18
Y	24.6	25.0	25.2	25.0	25.2	25.3	-	25.1	0.12
Pb	3	3	1	3	4	2	-	2.7	0.99
Zn	113	110	109	111	111	109	-	109.7	0.83
Ga	21	21	21	22	21	21	-	21.2	0.37
Ni	126	104	101	104	108	112	-	105.6	3.72
Cr	284	267	265	272	270	265	-	267.8	2.75
V	285	289	285	289	290	286	-	287.7	1.65
Ce	36	32	33	32	33	33	-	32.5	0.46
Ba	139	137	135	135	133	137	-	135.3	1.43
La	16	12	11	12	12	14	-	12.3	1.05

Facilities at the Ronald B. Gilmore XRF Lab

What we have:

To see some pictures of the lab, click here

What we do:

Table 2 from Rhodes: Geochemical stratigraphy of lava flows sampled by the Hawaii Scientific Drilling Project, JGR, Vol. 101, p. 11,737, May 10, 1996