Both Optically Stimulated Luminescence (OSL) dating and 14C dating are main dating method for archaeological sites, while their disagreements are quite often. In the Qaidam Basin (QB), human activity remains (HMRs) are frequently found within aeolian sediments, offering opportunities to make comparison between OSL and 14C ages, and to discuss their potential disagreements in archaeological sites. In this study, we present comparison between 18(10 of them had been published) OSL and 17 AMS 14C ages for samples from aeolian sediments in the eastern QB, including some samples from archaeological sites. Comparisons show better agreement in natural aeolian section, but more disagreements in sections with many HARs. This should be due to postdepositional anthropogenic disturbance, which can cause different influences to OSL and 14C ages. The age disagreement might display their different significances, with 14C chronology represent human activities, while OSL chronology more likely to reveal ages of original stratigraphy. Field hearth experiment was taken to check to what extent can heat from a hearth affect luminescence signals in the surrounding sediments. Results show that both OSL and Thermoluminescence signals in sediments under the hearths are not easy to be reset by the heat due to the poor downward thermal conductivity into the humid soil. This reminds the risk of OSL age overestimation for hearths. This study emphasizes the importance of cross-check between different dating methods for chronology building in archaeological contexts, and the necessity to analyze the dating materials, depositional process, and post-depositional disturbance when age disagreement is discovered.
- Luminescence dating
- Radiocarbon dating
- Archaeological site
- Anthropogenic disturbance
- Qaidam Basin
Chronology is a crucial scientific question for both archaeologic and paleoenvironmental studies on the Qinghai-Tibetan Plateau (QTP). However, archaeological studies in the Qaidam Basin (QB), NE QTP, are hindered. In the QB, very few early archaeological sites were found, because of the erosional environment, which is not suitable for the preservation of human activity remains (HARs). As a result, artifacts were usually found on the ground surface, e.g., Xiao Qaidam site (Huang
Methodologically, both OSL dating and 14C dating should be suitable for archaeological sites in aeolian sediments. Hou
In the Yutian site (
For archaeological sites, cross-check between OSL and 14C ages is crucial for confirming the chronology or revealing the potential disagreement. In this study, we provide a detailed cross-checking between OSL and AMS 14C dating in aeolian sediments, some of which contain HARs, to discover the disagreement and try to discuss the mechanisms by analyzing dating materials, depositional processes, and post-depositional disturbances.
The QB is located at the northern margin of the QTP (
The Hongshanzui (HSZ, 3172 m a.s.l.) site locates in a gully on a terrace of the Chahan Us River (
The Hebeicun (HBC, 3413 m a.s.l.) site is located at the east end of the modern Tiekui Desert, with aeolian sediments overlying on fluvial sediments (
The Xiarihal (XRH1, 3174 m a.s.l.) and XRH5 (3201 m a.s.l.) aeolian sections locate on the fluvial sediments of the Xiariha River terraces (
16 14C samples were taken from the HARs, and to compare with them, eight new OSL samples were taken. The detailed positions of the OSL samples are shown in
In the laboratory, the unexposed middle part of the tube was used to extract quartz for equivalent dose (De) determination. The samples were treated first with 10% HCl and then with 30% H2O2 to remove carbonates and organics, respectively. These samples are mainly from paleosol and loess, which are mainly composed of silt, so the major fraction of 38–63 μm was extracted by wet sieving. The samples were then etched by 35% H2SiF6 for about two weeks to remove feldspars (Lai
OSL measurements were made using an automated Risø TL/OSL-DA-20 reader equipped with blue diodes (λ = 470 ± 20 nm) and IR laser diodes (λ = 830 nm) in the laboratory of Qinghai Institute of Salt Lakes, Chinese Academy of Sciences. The luminescence was stimulated by blue LEDs at 130°C for 40 s, and detected using a 7.5 mm thick U-340 filter (detection window 275–390 nm) in front of the photomultiplier tube. Ninety percent diode power was used. Irradiations were carried out using a 90Sr/90Y beta source built into the Risø reader.
A preheat plateau test was conducted on sample HSZ1-4, and the preheat temperature of 220, 240, 260, 280 and 300°C was tested. The result showed a preheat plateau from 240 to 280°C, so 260°C for 10 s was chose as the preheat temperature for natural and regenerative doses, and cut-heat was at 220°C for 10 s for test doses in this study. For the younger sample HSZ2 and HSZ3, the preheat temperature was 220°C, and cutheat temperature was 200°C. Signals of the first four channels (0.64 s) stimulation were integrated for growth curve construction after background subtraction (last 10 seconds).
The validity of the SAR protocol was tested with a “dose recovery test” (Murray and Wintle, 2003). This test was conducted on sample HSZ1-4, and 6 aliquots were tested. The given laboratory dose was 5 Gy (approximately equal to its natural De), and the measured De was 4.8 ±0.41 Gy. Thus, the ratio of the measured to the given dose was 0.960 ± 0.082, suggesting that the SAR protocol is suitable for De determination. Recuperation was calculated by comparing the sensitivity-corrected OSL signal of 0 Gy to the sensitivity-corrected natural signal, and the recuperation was <3% for all samples. The “recycling ratio” was introduced to check for sensitivity change correction (Murray and Wintle, 2000), and for most aliquots, the recycling ratios fall into the acceptance range of 0.9–1.1.
In this study, the combination of SAR protocol (Murray and Wintle, 2000) and the Standardized Growth Curve (SGC) method (SAR-SGC method) (Roberts and Duller, 2004; Lai, 2006; Lai and Ou, 2013), was employed for De determination. For each sample, 6 aliquots were measured using the SAR protocol to get 6 growth curves which were then averaged to construct a SGC for this individual sample. Then 10–15 more aliquots were measured for the values of standardized natural signal (LN/TN) using the same measuring condition as used in the SAR protocol. Then the value of LN/TN of each of these 10–15 individual aliquots was then matched in the SGC to obtain a De. For each sample, the final De is the mean of all SAR Des and SGC Des.
The concentrations of U, Th and Κ were measured by neutron activation analysis. For the OSL samples in archaeological site, there are sometimes a lot of HARs within cultural layers, e.g. charcoals and ash, which can lower the average concentration of U, Th and Κ in sediments. Due to the limited thickness of cultural layer, the effect of heterogeneous environmental radionuclide concentration on the gamma dose rate should be considered. As a result, these foreign materials should be included in the buck samples for laboratorial U, Th and Κ concentration measurement according to their natural volume ratio in the sediments. Sampling location should also be taken into account, because to take a sample inside or outside a hearth will cause underestimation or overestimation to the effective gamma dose rate from surrounding sediments, respectively. Whether this influence could be ignored depends on the volume ratio of charcoals in the sediments and their distance to the OSL samples. In most sections, the effect of human activity remains to gamma dose rate could be ignored due to their extremely low ratio in the sediments. Even in the HSZ site with more HARs, environmental dose rates are not lowered compared with those in the same depth in HSZ2 and HSZ3 sections. HSZ 1-4 sample has lower dose rate due to higher ash ratio, this will not make the dose rate underestimated because it is really close to the underlying coarse fluvial sediments which usually have lower dose rate.
The water content, a crucial changing factor for dose rate, of each sample was measured. However, due to the seasonal and historic difference of soil moisture, it’s misleading to take the measured values as the historic mean values, alternatively, we take estimated values based on the measured value, mean measured value of loess in this region, and paleoclimatic changes (Yu and Lai, 2012, 2014;
For the 38–63 μm grains, the alpha efficiency value of quartz was taken as 0.035 ± 0.003 (Lai
Environmental radioactivity and OSL dating results. a
Sample ID Depth (m) K (%) Th (ppm) U (ppm) Water Content (%) Dose rate (Gy/ka) Aliquot Number De (Gy) OSL Age(ka) HSZ1-1 0.40 1.95 ±0.10 11.28 ±0.59 3.11 ±0.25 3±1 4.03 ± 0.21 6a+10b 2.6 ±0.1 0.65 ± 0.04 HSZ1-2 0.75 1.72 ±0.10 9.76 ± 0.55 3.28 ± 0.24 5±2 3.63 ± 0.20 6a+15b 3.1 ±0.1 0.86 ± 0.05 HSZ1-3 0.95 1.74 ±0.10 9.14 ±0.51 2.55 ± 0.22 5±2 3.39 ±0.19 6M1b 5.4 ±0.2 1.59 ±0.1 HSZ1-4 1.20 1.53 ±0.09 8.58 ± 0.53 2.36 ± 0.22 5±2 3.07 ±0.18 6M1b 5.1 ±0.3 1.65 ±0.1 HSZ2-1 0.40 1.78 ±0.09 10.29 ±0.55 3.17 ±0.24 5±2 3.72 ± 0.20 10a 0.190 ±0.010 0.05 ±0.01 HSZ3-1 0.45 1.76 ±0.09 10.19 ±0.54 2.56 ± 0.21 5±2 3.51 ±0.19 10a 0.195 ±0.012 0.06 ±0.01 HSZ3-2 0.75 1.77 ±0.09 9.83 ± 0.52 2.78 ± 0.22 5±2 3.55 ±0.19 6M3b 3.3 ±0.1 0.93 ± 0.06 HSZ3-3 1.30 1.86 ±0.10 10.26 ±0.54 3.15 ±0.25 7±3 3.62 ± 0.22 6a+15b 10.0 ±0.4 2.8 ±0.2
Environmental radioactivity and OSL dating results.
To make cross-check, 14C samples were mainly taken from the same layer as the OSL samples. Different dating materials were taken for 14C dating in this study, e.g., sheep dungs, charcoals, ash, and bones, so their significance for 14C dating should be analyzed for a better understanding of the results.
Charcoals are the most common materials for archaeological sites dating, and often offer good age control (e.g., Madsen
The ash, like the charcoals, is the remains of burnt plants, but it is powdery. Little charcoal pieces are usually floated from sediments for dating. As a result, it is dated as mixture of both herbaceous and woody plants, increasing the possibility of overestimation, though the herbaceous plants are not affected by the old carbon.
Animal dungs are not quite common in archaeological sites, but sometimes sheep dungs could be well preserved in arid regions. Sheep dungs used for 14C dating in this study are oval and carbonized, like the fresh sheep dungs in appearance. We assume that they have been baked in hearths; otherwise they were difficult to be preserved. They are different from ‘dry sheep dungs’, whose organic materials have been decomposed, with loess-like color and loose structure. The baked sheep dungs are suitable materials for 14C dating, because the dungs keep the same 14C/12C ratio, originated from the live grass and leaves eaten by the sheep, with the atmosphere at that time. This can avoid the contamination of ‘old carbon’, and offer the age of human activities. Additionally, being fragile, intact sheep dungs can minimize the possibility of re-transportation and redeposition, showing advantage on stratigraphic dating. Consequently, sheep dungs are ideal material for 14C dating in archaeological sites.
Bones can be dated by 14C dating with carbonate and collagen, and the latter is more welcomed. However, bulk collagen age estimates are also generally thought to be limiting ages since the proteins in collagen degrade differentially (e.g., Minami
15 AMS 14C samples (charcoals, ash, bones, and sheep dungs) were measured in AMS Laboratory at the School of Archaeology and Museology of Peking University; while another two charcoal samples were dated in Xi’an AMS Center, Institute of Earth Environment, Chinese Academy of Sciences. The ash samples were pretreated to flotation the charcoal pieces for dating, while collagen were extracted from bone samples for dating. The detailed pretreat and measure processes for charcoals (including carbonized sheep dungs) and collagen follow the routine method applied in Peking University (Qiu, 1990). The radiocarbon ages were then calibrated into calendar years using the INTCAL 13 calibration.
Results of AMS 14C dating.
Sample ID Lab Code Materials 14C Ages (14C BP) Calender ages (Cal BP) OSL ages (ka) and references HSZ1-0.40 BA101622 sheep dung 540 ± 25 539 ± 14 0.650 ± 0.04, this study HSZ1-0.75 BA101623 sheep dung 1075 ± 25 968 ± 17 0.860 ± 0.05, this study HSZ1-0.90 BA101626 charcoal 880 ± 20 768 ± 27 1.6 ± 0.1, this study HSZ1-1.20 BA101625 charcoal 2975 ± 25 3160 ± 22 1.7 ±0.1, this study HSZ3-0.80 BA101620 bone 460 ± 35 514 ± 14 0.93 ± 0.06, this study HBC7 XA14483 charcoal 2517 ± 24 2563 ± 26 no HBC1-3.25 BA101621 bone 1245 ± 25 1230 ± 31 1.6 ± 0.1, Yu HBC1-3.25* BA101624 charcoal 1490 ± 30 1373 ± 28 1.6 ± 0.1, Yu HBC7-C2 XA10486 charcoal 1802 ± 28 1663 ± 22 no XRH1-1.00 BA101630 Charcoal 3030 ± 25 3227 ± 22 3.3 ± 0.2, Yu and Lai (2014) XRH1-1.20 BA101631 charcoal 995 ± 25 924 ± 15 3.4 ± 0.3, Yu and Lai (2014) XRH1-1.60 BA101632 charcoal 3435 ± 30 3679 ± 41 4.0 ± 0.3, Yu and Lai (2014) XRH1-3.00 BA101633 charcoal 5925 ± 40 6752 ± 47 7.4 ± 0.6, Yu and Lai (2014) XRH1-3.95 BA101634 charcoal 6605 ± 35 7488 ± 26 7.9 ± 0.6, Yu and Lai (2014) XRH5-4.65 BA101628 ash 4575 ± 35 5305 ± 17 7.2 ± 0.6, Yu and Lai (2014) XRH5-5.55 BA101627 charcoal 4090 ± 25 4557 ± 30 5.3 ± 0.4, Yu and Lai (2014) XRH5-6.25 BA101629 ash 5295 ± 40 6079 ± 39 8.2 ± 0.8, Yu and Lai (2014)
Results of AMS 14C dating.
In the HSZ1 section, both OSL and 14C ages increase with depth and the upper two pairs of ages are in agreement. However, the lower two 14C ages disagree with the OSL ages, especially the lowest one (3.160 ±0.022 Cal BP vs. 1.7 ±0.1 ka). This makes it confuse that when did the aeolian sediments accumulation and human activities start. Was this caused by the overestimation of 14C age or the underestimation of OSL age? Age-depth model based on OSL ages shows stable accumulation rate in HSZ3 section, suggesting that the OSL ages should be reliable. According to the age-depth model, loess should start at
There are many other disagreements on ages, e.g., the 2nd and 3rd14C ages in HSZ1 section are disordered, and the 14C age of a bone (514 ± 14 Cal BP) is
OSL age at 40 cm of the HSZ2 section is 0.05 ± 0.01 ka, similar with HSZ3-1 (0.06 ±0.01 ka) from 50 cm depth in the HSZ3 section. This repeatability of the young ages shows the OSL dating is suitable for the young samples in the archaeological site. These two ages are much younger than that from the same depth in the HSZ1 section
The anthropogenic layer at the depth of 3.2–3.3 m in the HBC1 section was dated to younger than 1.6 ± 0.1 ka by OSL dating (Yu
Chronology of the XRH1 section has been well established by ten OSL ages in Yu and Lai (2014). Five charcoals were dated by 14C dating in this study, and four of them could be well compared with the OSL dating result, except the one at the depth of 1.2m (0.924 ± 0.015 Cal BP vs. 3.4 ± 0.3 ka). This charcoal is very tiny (<2 mm), the cause for the serious underestimation is unknown. Without much anthropogenic disturbance, the age-depth model based on both OSL and 14C ages show stable accumulation rate of aeolian sediments.
The XRH5 section has also been dated by 16 OSL ages (Yu and Lai, 2014). Age-depth model based on OSL ages show consistent depositional rate in the upper section, however, both OSL and 14C ages are disorder in the lower section. Tow age-depth models could be identified, with similar depositional rate but different ages. The younger model based on both OSL and 14C ages seems consistent with the upper section, however, the disorder of 14C ages is difficult to interpretation, because the younger 14C age (4567 ± 30 Cal BP) based on ash should not be underestimated. Consequently, the sediments should have been seriously disturbed. For the OSL ages, the age-depth model is neither robust, the two older OSL age (8.9 ± 0.5 ka and 8.9 ± 0.4 ka) from thin sand layers might be caused by the underestimated dose rate, and possible insufficient bleaching, while the two younger ones (5.3 ± 0.4 ka and 6.2 ± 0.5 ka) might be due to the bleaching caused by disturbance. According to the 14C ages in the lower section, human activities exited during
Murray and Olley (2002) reviewed comparisons between OSL ages and 14C ages or other independent ages and found most of them could be well compared, especially for the ages from aeolian sediments. This conclusion is also proved by ages from the XRH1 section in this study, in which no direct human activity evidences were founded. However, it is obvious that anthropogenic disturbance is important for chronologies in archaeological sites. In the HSZ1 and XRH5 sections, the 14C ages are obviously younger than the OSL ages, and disorder occur on both OSL and 14C ages due to the stratigraphic disturbances. Influences increase with the frequency and intensity of human activities. In the archaeological sites, human and livestock activities could usually disturb the stratigraphy, especially for the surficial sediments within 0.3-0.5 m. Stratigraphic disturbances could mix sediments from different depth unequally, due to the insufficient bleaching, OSL ages may show underestimation or overestimation in different layer compared with their original stratigraphie ages. Disturbances can also change original location and depth of the carbonaceous materials synchronously, and in this case, the 14C ages can represent the ages of the burning events (plants or animals dead), but not the ages of the surrounding sediments. As a result, stratigraphy disturbance should be the major cause for the disagreement between OSL and 14C ages in the archaeological sites. In this case, accumulation processes and post-depositional artificial disturbances should be analyzed. However, these problems are usually difficult to be found if without detailed chronological studies, or are ignored. The disagreement between OSL and 14C ages and disorder of ages in the HSZ region by Niu
When people use fire on the ground, hearths surrounded by stones were usually built, like those in the Qinghai Lake Basin (Madsen
During the building and abandon of a hearth, firstly, a pit was dug on the ground, and then fire was set, leaving an ash layer, and finally, the fire and ash was covered to extinguish the fire. During this process, the sediments around the hearth were baked by the high temperature.
In this case (
In consideration of the poor thermal conductivity of the sediments, how many surrounding sediments could be heated sufficiently enough to reset the luminescence signals is a fatal question. To examine the influence of heating events on OSL signals in the surrounding sediments, an experiment was carried out in the field (
This remind us that if 14C ages not match OSL ages under a hearth, it might be due to the OSL signals were not reset to represent the heating event. Worse still, the possibly disturbed OSL ages should also be cautioned to use as the stratigraphic ages. As a result, when dating a hearth, it’s not advisable to take OSL sample beneath it. This is to raise the potential problems, but not to deny the possibility to date hearths with OSL. If the hearth was built by stones directly on the ground surface without artificial or natural erosion,
The disorder of 14C ages in HSZ1 section implies that the age-depth model based on 14C ages is not reliable. The 14C ages only represent human activities in two periods, but nothing with the ages of stratigraphy. OSL ages in the HSZ3 section, which are more reliable due to fewer disturbances, indicate the OSL ages in HSZ1 section are neither reliable due to the severe disturbance and insufficient bleaching. The only implication of OSL ages in HSZ1 section is to display the influence of disturbances. In the lower HBC5 section, the left younger age-depth model based on 14C ages represent the age of human activities again. Their disorder and much younger than OSL ages imply that the stratigraphy was severely disturbed, and consequently, neither of the age-models can represent the ages of the stratigraphy.
These disagreements between 14C and OSL ages demonstrate their different implications in archaeological sites. Usually, 14C ages can represent human activities, if not affected by old carbon. 14C ages from different material can help to identify the disturbances and to limit the age ranges. OSL ages represent ages of the sediments in sections with fewer disturbance. However, it’s also difficult to date the sediments with OSL dating in sections with intensive disturbance. Though influenced by underestimation, OSL ages should still close to the original stratigraphic ages, and difficult to represent human activities, even if intensively affected as demonstrated in HSZ1, XRH5, and
The different implications of OSL and 14C ages are crucial for both archaeological and paleoenvironmental studies. Firstly, if archaeological sites are aimed to dated, directly dating on HARs and/or fossils (e.g., ESR and U-series dating on teeth) should be suggested, because indirect dating of sediments might be overestimated due to disturbance, especially for old sites without proper dating methods or materials for cross-checking. Secondly, neither OSL nor 14C is suitable for dating of sediments to study paleoenvoronmental background reconstruction in archaeological sites due to disturbances.
Both OSL and 14C dating are suitable for the dating of aeolian sediments, but disagreements occur quite often in archaeological sites in the QB. The disagreements were caused by the anthropogenic disturbances to the sediments and HARs, which can mix sediments (OSL) and HARs (14C) in different depth. Field hearth experiment revealed that even intensive fire events cannot reset luminescence signals in sediments 5-cm-depth beneath the hearth. As a consequence, both stratigraphic disturbances and using fire are difficult to totally reset the OSL signals in surrounding sediments. This is the reason why OSL ages usually older than the corresponding 14C ages in archaeological sites.
In archaeological sites, OSL and 14C ages seem display different implications,
Environmental radioactivity and OSL dating results.
|Sample ID||Depth (m)||K (%)||Th (ppm)||U (ppm)||Water Content (%)||Dose rate (Gy/ka)||Aliquot Number||De (Gy)||OSL Age(ka)|
|HSZ1-1||0.40||1.95 ±0.10||11.28 ±0.59||3.11 ±0.25||3±1||4.03 ± 0.21||6a+10b||2.6 ±0.1||0.65 ± 0.04|
|HSZ1-2||0.75||1.72 ±0.10||9.76 ± 0.55||3.28 ± 0.24||5±2||3.63 ± 0.20||6a+15b||3.1 ±0.1||0.86 ± 0.05|
|HSZ1-3||0.95||1.74 ±0.10||9.14 ±0.51||2.55 ± 0.22||5±2||3.39 ±0.19||6M1b||5.4 ±0.2||1.59 ±0.1|
|HSZ1-4||1.20||1.53 ±0.09||8.58 ± 0.53||2.36 ± 0.22||5±2||3.07 ±0.18||6M1b||5.1 ±0.3||1.65 ±0.1|
|HSZ2-1||0.40||1.78 ±0.09||10.29 ±0.55||3.17 ±0.24||5±2||3.72 ± 0.20||10a||0.190 ±0.010||0.05 ±0.01|
|HSZ3-1||0.45||1.76 ±0.09||10.19 ±0.54||2.56 ± 0.21||5±2||3.51 ±0.19||10a||0.195 ±0.012||0.06 ±0.01|
|HSZ3-2||0.75||1.77 ±0.09||9.83 ± 0.52||2.78 ± 0.22||5±2||3.55 ±0.19||6M3b||3.3 ±0.1||0.93 ± 0.06|
|HSZ3-3||1.30||1.86 ±0.10||10.26 ±0.54||3.15 ±0.25||7±3||3.62 ± 0.22||6a+15b||10.0 ±0.4||2.8 ±0.2|
Results of AMS 14C dating.
|Sample ID||Lab Code||Materials||14C Ages (14C BP)||Calender ages (Cal BP)||OSL ages (ka) and references|
|HSZ1-0.40||BA101622||sheep dung||540 ± 25||539 ± 14||0.650 ± 0.04, this study|
|HSZ1-0.75||BA101623||sheep dung||1075 ± 25||968 ± 17||0.860 ± 0.05, this study|
|HSZ1-0.90||BA101626||charcoal||880 ± 20||768 ± 27||1.6 ± 0.1, this study|
|HSZ1-1.20||BA101625||charcoal||2975 ± 25||3160 ± 22||1.7 ±0.1, this study|
|HSZ3-0.80||BA101620||bone||460 ± 35||514 ± 14||0.93 ± 0.06, this study|
|HBC7||XA14483||charcoal||2517 ± 24||2563 ± 26||no|
|HBC1-3.25||BA101621||bone||1245 ± 25||1230 ± 31||1.6 ± 0.1, Yu |
|HBC1-3.25*||BA101624||charcoal||1490 ± 30||1373 ± 28||1.6 ± 0.1, Yu |
|HBC7-C2||XA10486||charcoal||1802 ± 28||1663 ± 22||no|
|XRH1-1.00||BA101630||Charcoal||3030 ± 25||3227 ± 22||3.3 ± 0.2, |
|XRH1-1.20||BA101631||charcoal||995 ± 25||924 ± 15||3.4 ± 0.3, |
|XRH1-1.60||BA101632||charcoal||3435 ± 30||3679 ± 41||4.0 ± 0.3, |
|XRH1-3.00||BA101633||charcoal||5925 ± 40||6752 ± 47||7.4 ± 0.6, |
|XRH1-3.95||BA101634||charcoal||6605 ± 35||7488 ± 26||7.9 ± 0.6, |
|XRH5-4.65||BA101628||ash||4575 ± 35||5305 ± 17||7.2 ± 0.6, |
|XRH5-5.55||BA101627||charcoal||4090 ± 25||4557 ± 30||5.3 ± 0.4, |
|XRH5-6.25||BA101629||ash||5295 ± 40||6079 ± 39||8.2 ± 0.8, |