Citation:

PANGAEA.897146

Name: High-resolution analysis of X-ray fluorescence (XRF) elemental counts from the Nyabuiyabuyi wetland sediment core, Eastern Mau, Kenya
Creator: Esther Githumbi
Published: 2019-01-08
License: https://creativecommons.org/licenses/by/4.0/

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Published: 2019-01-08 • DOI registered: 2019-02-07

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Abstract:

This data provides a description of the elemental profile of a 537 cm sediment core covering the last ~16,000 cal yr BP retrieved from the Nyabuiyabuyi wetland, Eastern Mau, Kenya. This data was part of a study to provide a multi-proxy data set from which we can understand the interactions between vegetation change, fire regimes and wetland development since the Late Glacial period. Such a record improves our understanding of forest development through the Holocene as well as providing a comparison with other highland forest sites in East Africa such as Mt. Kenya, the Aberdare Ranges, Mt. Elgon and Mt. Kilimanjaro.

A high-resolution analysis of X-ray fluorescence (XRF) elemental counts and magnetic susceptibility are used to trace amounts of terrigenous input which occur during periods of high sedimentation as a result of either increased erosion in wet periods or open ecosystems during arid periods. Periods of increased human activities are identified by the appearance and increase of chemical elements not detected previously and can be correlated with historical records.

The core faces were cleaned and scanned with a Cox Analytical Systems ITRAXTM core scanner at the Department of Geography and Earth Sciences, Aberystwyth University, UK. Optical imagery of the core face was collected with a RGB camera, magnetic susceptibility was measured with a Bartington MS2E sensor at 1 centimetres intervals and air corrected between measurements. Twenty two elements were examined at 0.05 centimetre intervals through x-ray fluorescence (XRF) with a 3kW water-cooled Mo anode x-ray tube operating at 60 kV, 35 mA, 200 ms exposure, 10s dwell time every 500 microns giving readings in thousands of counts per second (kcps).

Related to:

Githumbi, Esther (2017): Holocene environmental and human interactions in East Africa [dissertation]. University of York, https://etheses.whiterose.ac.uk/19515

Coverage:

Latitude: -0.436470 * Longitude: 35.799500

Date/Time Start: 2014-04-01T00:00:00 * Date/Time End: 2014-04-01T00:00:00

Minimum DEPTH, sediment/rock: 0.0000 m * Maximum DEPTH, sediment/rock: 4.8400 m

Event(s):

Nyabuiyabuyi_wetland * Latitude: -0.436470 * Longitude: 35.799500 * Date/Time: 2014-04-01T00:00:00 * Elevation: 2919.0 m * Recovery: 5.37 m * Method/Device: Hand push corer (HSR) * Comment: Core sampled using the hand pushed
Russian D-shaped corer in 50 cm drives with 10 cm overlapped sections.

Comment:

XRF-ITRAX from a wetland sediment core (cored in March 2014) located in the Mau Forest Complex. The sediment core was scanned in July 2014 at a resolution of 500 microns and 22 elements were identified.

Comment to the parameter Quality flag (Validity):

Validity 1 is potentially good data. Validity 0 is potentially poor quality data. Validity relates to if the detector has been in position during analysis. Validity 0 is common at the beginning and end of each section where the detector is not able to get close enough to the core surface. This is also the case when the surface profile of the core is uneven. This may occur often in your datasets due to your sediments being coarse, and the uneven nature of the split core surface.

Parameter(s):

#	Name	Short Name	Unit	Principal Investigator	Method/Device	Comment
1	DEPTH, sediment/rock	Depth sed	m	Githumbi, Esther		Geocode
2	Distance, sample to detector	Dist sample detector	mm	Githumbi, Esther	X-ray fluorescence ITRAX core scanner	Distance between laser and sample surface
3	Quality flag	QF		Githumbi, Esther	X-ray fluorescence ITRAX core scanner	validity: 1=flat surface, 0=undulating surface (see comments)
4	Parameter	Parameter	arbitrary units	Githumbi, Esther	X-ray fluorescence ITRAX core scanner	E-gain [eV]
5	Parameter	Parameter	arbitrary units	Githumbi, Esther	X-ray fluorescence ITRAX core scanner	E-offset [eV/Ch]
6	Parameter	Parameter	arbitrary units	Githumbi, Esther	X-ray fluorescence ITRAX core scanner	F-slope
7	Parameter	Parameter	arbitrary units	Githumbi, Esther	X-ray fluorescence ITRAX core scanner	F-offset [mm]
8	Total count rate	TCR	kcps	Githumbi, Esther	X-ray fluorescence ITRAX core scanner
9	Mean squared error	MSE		Githumbi, Esther	X-ray fluorescence ITRAX core scanner
10	Aluminium	Al	cps	Githumbi, Esther	X-ray fluorescence ITRAX core scanner
11	Silicon	Si	cps	Githumbi, Esther	X-ray fluorescence ITRAX core scanner
12	Phosphorus	P	cps	Githumbi, Esther	X-ray fluorescence ITRAX core scanner
13	Sulfur	S	cps	Githumbi, Esther	X-ray fluorescence ITRAX core scanner
14	Chlorine	Cl	cps	Githumbi, Esther	X-ray fluorescence ITRAX core scanner
15	Argon	Ar	cps	Githumbi, Esther	X-ray fluorescence ITRAX core scanner
16	Potassium	K	cps	Githumbi, Esther	X-ray fluorescence ITRAX core scanner
17	Calcium	Ca	cps	Githumbi, Esther	X-ray fluorescence ITRAX core scanner
18	Titanium	Ti	cps	Githumbi, Esther	X-ray fluorescence ITRAX core scanner
19	Manganese	Mn	cps	Githumbi, Esther	X-ray fluorescence ITRAX core scanner
20	Iron	Fe	cps	Githumbi, Esther	X-ray fluorescence ITRAX core scanner
21	Nickel	Ni	cps	Githumbi, Esther	X-ray fluorescence ITRAX core scanner
22	Copper	Cu	cps	Githumbi, Esther	X-ray fluorescence ITRAX core scanner
23	Zinc	Zn	cps	Githumbi, Esther	X-ray fluorescence ITRAX core scanner
24	Bromine	Br	cps	Githumbi, Esther	X-ray fluorescence ITRAX core scanner
25	Rubidium	Rb	cps	Githumbi, Esther	X-ray fluorescence ITRAX core scanner
26	Strontium	Sr	cps	Githumbi, Esther	X-ray fluorescence ITRAX core scanner
27	Yttrium	Y	cps	Githumbi, Esther	X-ray fluorescence ITRAX core scanner
28	Zirconium	Zr	cps	Githumbi, Esther	X-ray fluorescence ITRAX core scanner
29	Iodine	I	cps	Githumbi, Esther	X-ray fluorescence ITRAX core scanner
30	Mercury	Hg	cps	Githumbi, Esther	X-ray fluorescence ITRAX core scanner
31	Lead	Pb	cps	Githumbi, Esther	X-ray fluorescence ITRAX core scanner
32	Correction	corr		Githumbi, Esther	X-ray fluorescence ITRAX core scanner	Diffraction peak correction
33	Correction	corr		Githumbi, Esther	X-ray fluorescence ITRAX core scanner	Sum Peak Correction 1
34	Correction	corr		Githumbi, Esther	X-ray fluorescence ITRAX core scanner	Sum Peak Correction 2
35	Correction	corr		Githumbi, Esther	X-ray fluorescence ITRAX core scanner	Sum Peak Correction 3
36	Incoherent scatter, counts	icoh scat	cts	Githumbi, Esther	X-ray fluorescence ITRAX core scanner	Compton radiation scattering, Incoherent scatter (from the Molybdenum x-ray tube)
37	Coherent scatter, counts	Coh scat	cts	Githumbi, Esther	X-ray fluorescence ITRAX core scanner	Rayleigh radiation scattering, Coherent scatter (from the Molybdenum x-ray tube)

License:

Creative Commons Attribution 4.0 International (CC-BY-4.0)

Size:

348516 data points

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