Integrated interpretation of pXRF data on ancient nephrite artifacts excavated from Tomb No.1 in Yuehe Town, Henan Province, China

Previous studies of ancient jade using portable X-ray fluorescence (pXRF) have mostly focused on mineral identification, alteration status and provenance determination. It is usually used as an auxiliary instrument for spectroscopic detection with finer resolution. However, there is no substitute for the efficiency and stability of pXRF in-situ non-destructive analysis, which is less affected by the test environment. The scale of the data from the pXRF analysis did not allow for a more in-depth interpretation of ancient jade in the past. In this study, pXRF has been carried out for a total of 112 pieces of nephrite artifacts unearthed from the Yuehe tomb No.1 in Nanyang City, Henan Province, Central China. Certain patterns become clearer as the size of the data increases. The coefficient of variation, cluster analysis and correlation analysis can be used to separate elements into different assemblages, revealing whether the elements are from the primary and impurity minerals of nephrite itself, from the burial microenvironment in the soil, or even from other specific sources. In addition, most of the secondary whitening occurring in the batch of nephrite are accompanied by an increase in Ca content, confirming the previously refuted theory of calcification. More importantly, the principal component analysis of the twin nephrite artifacts suggests visually indistinguishable elemental changes caused by secondary changes, which may lead to misjudgment of ancient nephrite provenance using elemental data.

Supplemental Material: Retroarc Jurassic burial and exhumation of Barrovian metamorphic rocks dated by monazite petrochronology, Funeral Mountains, California

All isotope and elemental data collected and presented in this paper. Table S1 includes monazite isotopic data for U-Th-Pb, element abundances, calculated chondrite normalized REE values, and calculated ages. Table S2 includes xenotime isotopic data for U-Th-Pb, element abundances, calculated chondrite normalized REE values, and calculated ages. Table S3 includes garnet element abundances and chondrite normalized REE data collected along rim-to-rim line traverses.<br>

Supplemental Material: Retroarc Jurassic burial and exhumation of Barrovian metamorphic rocks dated by monazite petrochronology, Funeral Mountains, California

All isotope and elemental data collected and presented in this paper. Table S1 includes monazite isotopic data for U-Th-Pb, element abundances, calculated chondrite normalized REE values, and calculated ages. Table S2 includes xenotime isotopic data for U-Th-Pb, element abundances, calculated chondrite normalized REE values, and calculated ages. Table S3 includes garnet element abundances and chondrite normalized REE data collected along rim-to-rim line traverses.<br>

Integrated Interpretation of pXRF Data on Ancient Nephrite Artifacts Excavated from Tomb No.1 in Yuehe Town, Henan Province, China

Previous studies of ancient jade using portable X-ray fluorescence (pXRF) have mostly focused on mineral identification, alteration status and provenance determination. It is usually used as an auxiliary instrument for spectroscopic detection with finer resolution. However, there is no substitute for the efficiency and stability of pXRF in-situ non-destructive analysis, which is less affected by the test environment. The scale of the data from the pXRF analysis did not allow for a more in-depth interpretation of ancient jade in the past. In this study, pXRF has been carried out for a total of 112 pieces of nephrite artifacts unearthed from the Yuehe tomb No.1 in Nanyang City, Henan Province, Central China. Certain patterns become clearer as the size of the data increases. The coefficient of variation, cluster analysis and correlation analysis can be used to separate elements into different assemblages, revealing whether the elements are from the primary and impurity minerals of nephrite itself, from the burial microenvironment in the soil, or even from other specific sources. In addition, most of the secondary whitening occurring in the batch of nephrite are accompanied by an increase in Ca content, confirming the previously refuted theory of calcification. More importantly, the principal component analysis of the twin nephrite artifacts suggests visually indistinguishable elemental changes caused by secondary changes, which may lead to misjudgment of ancient nephrite provenance using elemental data.

Using XRF Elemental Data and XRD Direct Measured Mineralogy for an Accurate Wellbore Placement and Geosteering through Carbonates Reservoirs* Drilled Within 04 ½" Slim Hole: A Case Study from a Jurassic Middle Marrat Carbonates Reservoir-Kuwait

ABSTRACT As the pursuit of oil and gas in Middle East Jurassic carbonates reservoirs grows, it is increasingly evident that horizontal wellbore placement, or targeting, plays a first-order role in the production capability of a well. Indeed, the percentage of a wellbore "in target" is a common metric used when evaluating the causes for good or poor production from any particular well. The most common process used for geosteering a horizontal wellbore into a chosen target is the correlation of logging-while-drilling (LWD) total gamma-ray (GR) to a vertical pilot-hole GR log or offset wells GR logs. However, limitations inherent to this procedure can reduce the ability to effectively use LWD GR data due to 4 ½" slim hole diameter and mud telemetry issues, the non-descript signal from LWD tools due to high pressure and high temperature and the possibility of lost signal from LWD tools. In addition, the thickness of MRW-F11 targeted reservoir is limited to plus or minus 22 ft and low GR contrast from bed to bed might lead to loss of directional control in the target MRW-F11. To accurately geosteer a well, Geochemical analyses of drilled cuttings are proposed to assist well placement. The analyses performed were elemental data derived from energy-dispersive X-ray fluorescence (ED-XRF) and mineralogical quantitative content acquired from the direct measurement from energy-dispersive X-ray Diffraction (ED-XRD). The Elemental and mineralogy data were acquired from drilling cuttings taken at ten feet intervals, from two offsets wells. The mineral and elemental data were used to build a chemo-stratigraphic profile and zonation of the sedimentary section. Chemo-stratigraphic zones are defined as having multiple elements and keys ratios (where possible) which illustrate distinct changes in chemical and mineralogical composition profiles from one zone to another. These zones were correlated over reasonable distances (at a minimum the length of the horizontal wellbore) and can be readily identifiable in cuttings. Using these criteria chemo-stratigraphic zonation's have been constructed in the Middle Marrat formation going from MRW-F1 toward MRW-F11 layer. Well site ED-XRF and ED-XRD data were used in conjunction with LWD Gamma Ray to geosteer at approximately 22 feet thin zone which resides at the base of an approximately 100 ft thick reservoir carbonate section of the main MRW-F11 reservoir. The LWD GR Signal was 45 ft behind the bit while all XRF and XRD data were at plus or minus 5 feet while sliding at plus or minus 10 ft in rotary mode and with a controlled slow rate of penetration (ROP) of 10 ft/hr. Geochemical rock analyses (GEAR) using XRF & XRD chemical analyses was the unique reference for approximately 500 ft interval to geosteer the well when LWD lost the signal, wiper trip was cancelled which considerably reduced drilling costs. Well site XRF and XRD data was successfully applied to geosteer the well, determine the position of the wellbore in zones of non-descript LWD GR signature, and determine the lateral extent of the reservoir interval.