Bulk Chemical Composition of the Ningqiang Carbonaceous Chondrite： An Issue of Classification

The Ningqiang meteorite is a fall carbonaceous chondrite, containing various Ca-, Al-rich inclusions that usually escaped from secondary events such as high-temperature heating and low- temperature alteration. However, it has not yet been classified into any known chemical group. In order to address this issue, 41 elements of the bulk Ningqiang meteorite were analyzed using inductively coupled plasma mass spectrometry （ICP-MS） and inductively coupled plasma atom emission spectrometry （ICP-AES） in this study. The Allende （CV3） carbonaceous chondrite and the Jilin （H5） ordinary chondrite were also measured as references, and our analyses are consistent with the previous results. Rare earth and other refractory lithophile elements are depleted in Ningqiang relative to both Allende and mean CK chondrites. In addition, the REE pattern of Ningqiang is nearly flat, while that of Allende shows slight enrichment of LREE relative to HREE. Siderophile elements of Ningqiang are close to those of mean CK chondrites, but lower than those of Allende. Our new analyses indicate that Ningqiang cannot be classified into any known group of carbonaceous chondrites, consistent with previous reports.     

Rare Earth Element Geochemistry of Late Palaeozoic Coals in North China

Instrumental Neutron Activation Analysis (INAA) was done to determine the abundances of rare earth elements (REE) of 58 samples of Late Palaeozoic Carboniferous-Permian coals and related rocks in North China. Detailed study of REE geochemistry shows that the ∑REE of most coals studied in this paper is in a normal range between 30×10-6 and 80×10-6 with a mean of 56×10-6. The REE in the Taiyuan Formation in the northern part of North China are much richer than those in the southern part. This is due to the shorter distance to the source area in the north. Moreover, the IREE is in positive correlation to coal ash, especially closely related to the content of clay minerals <2μm in size. This reveals that most REE were carried by terrigenous clastic materials, especially fine clay minerals. In the coals the light REE (LREE) are much richer than the heavy REE (HREE), and the LREE/HREE ratio in coals generally varies from 2 to 8. The LREE/HREE ratio of high-ash, low-sulphur coals is higher than that of lo     

Geochemical Behaviors of REE and Other Trace Elements during the Formation of Strata-bound Skarns and Related Deposits: A Case Study of the Dongguashan Cu (Au) Deposit, Anhui Province, China

REE and other trace elements in the altered marbles, massive skarns and ores, as well as garnet and quartz were determined in order to examine the behaviors of trace elements during hydrothermal alteration. It is demonstrated that the high-field-strength (HFS) elements Zr, Hf, Th and Nb were immobile while other trace elements were mobile during the formation of skarns and related deposits. REE and ore-forming elements such as Cu and Ag in hydrothermally-altered marbles and skarns were provided primarily by hydrothermal fluids. In the direction transverse of the strata, the more deeply the marbles were altered, the higher the total REE abundance and the larger the negative Eu anomalies would be. The chondrite-normalized REE patterns of skarns are similar to those of the marbles, but the former are distinguished by much higher REE contents and more remarkable negative Eu anomalies. Those patterns were apparently not inherited from the marble protolith, but were controlled by garnets, which were determine     

Thermal and Collision History of Jilin（H5） and Qingzhen（EH3） Chondrites

This paper deals with the effects of thermal and collision events which had been experienced by the Jilin(H5) and Qingzhen(EH3) chondrites before they fell to the earth .The HRTEM and opti-cal microscopic investigations show that the Jilin chondrite has undergone more extensive thermal heating and two stages of collision,while the Qingzhen chondrite has experienced weak thermal events after the accretion of its parent body and one stage of moderate collision.The schematic dia-grams of the process of formation and evolution of these two meteorites are given in the present pa-per.     

Geochemical Characteristics and Implications of Eclogite Gravels from Mesozoic Strata at the Northern Margin of Dabie Orogenic Belt

The eclogite gravels, which were found in the Mesozoic Fenghuangtai and Maotanchang formations on the northern margin of the Dabie orogenic belt, are rich in K2O(1.21%),∑REE (278μg/g) ,and LILE(such as Rb, Ba, K, Th, etc.) , with high (La/Yb)N ratios(14.4),on the basis of the analyses of major elements, rare-earth elements (REE) and trace elements. Their enrichment in LILE, notable Nb-Ta depletion through, and depletion in HFSE relative to REE in comparison with the primitive mantle and N-MORB indicate that the protoliths of the eclogite gravels were formed in an island-arc setting. According to the Th-Hf-Ta discrimination diagram, the protoliths of the eclogite gravels are characterized by volcanic arc basalts.Trace element data indicate that the subducted marine sediments were assimilated in the magma chamber, resulting in the enrichment of LILE in the protoliths. Therefore, the protoliths of the eclogite gravels are considered to have been formed in an inland-arc setting, indicating that there had developed a paleo-inland arc before Triassic collision between the North and South China blocks in the Dabie orogenic belt. There is a marked difference between the eclogite gravels and the eclogites developed along the Dabie orngenic belt, solely based on their geochemical data,especially REE. Therefore, the eclogite gravels may not be derived from eclogite terrains preserved in the Dabie orogenic belt.     

Geochemistry of meta-volcanic rocks from the Longbohe Cu deposit, Yunnan Province, China： Implications for the genesis and tectonic setting

The Longbohe Cu deposit, which is located in the southern part of the Honghe ore-forming zone, Yunnan Province, China, belongs to a typical ore field where volcanic rocks are of wide distribution and are associated with Cu mineralization in time and space. The volcanic rocks in the ore field, which have experienced varying degree of alteration or regional metamorphism, can be divided into three types, i.e., meta-andesite, meta-subvolcanic rock and meta-basic volcanic rock in accordance with their mineral assemblages. These three types of volcanic rocks in the ore field are relatively rich in Na and the main samples plot in the area of alkali basalts in the geochemical classification diagram. With the exception of very few elements, these three types of volcanic rocks are similar in the content of trace elements. In comparison to the basalts of different tectonic settings, the meta-volcanic rocks in the ore field are rich in high field strength elements (HFSE) such as Th, Nb, etc. and depleted in large ion lithophile elements (LILE) such as Sr, Ba, etc. and their primary mantle-normalized trace element patterns show remarkable negative Th and Nb anomalies and negative Sr and Ba anomalies. These three types of volcanic rocks are similar in REE content range and chondrite-normalized REE patterns with the exception of Eu anomaly. Various lines of evidence show that these three types of volcanic rocks in the ore field have the same source but are the products of different stages of magmatic evolution, their original magma is a product of partial melting of the metasomatically enriched mantle in the tensional tectonic setting within the continent plate, and the crystallization differentiation plays an important role in the process of magmatic evolution.     

The geochemical characteristics of aqueous rare-earth elements in shallow karst groundwater in Guiyang City,China

Fifty-seven shallow groundwater samples were collected from Guiyang karst basin, China, to analyze the aqueous rare-earth elements in low-water seasons and it is shown that the total amount of rare-earth elements (ΣREE) in karst groundwater is exceedingly low compared with that in carbonate rocks or weathering crusts of carbonate rocks, and ranges from 0.01 to 0.43, from 0.03 to 0.27, from 0.03 to 0.19 and from 0.05 to 1.38 μg·L-1 for dolomite, dolomitic & limestone, limestone and clastic rock aquifer, respectively. Both distributions and contents of rare-earth elements (REE) in karst groundwater reflect the lithology of host rocks or weathering crusts of carbonate rocks through which groundwater flows. The chondrite-normalized patterns show a non-flat profile with higher enrichment of slightly light rare-earth elements (LREE) than heavy rare-earth elements (HREE), prominent fractionation between LREE and HREE, negative Ce anomalies and negative or positive Eu anomalies. There is more obvious fractionation between LREE and HREE in groundwater than that in carbonate rocks and their weathering crusts due to high contents of HCO3? and PH in groundwater. In shallow karst groundwater, REE(CO3)n2n-3 (n=1 and 2) is the main inorganic species of REE. But for a clastic rock aquifer, both REESO4+ and REECO3+ are the main inorganic species of REE. Species of REE in groundwater is closely associated with the hydrochemical type of groundwater which is predominated by the lithology of host rocks, groundwater-rock interaction and weathering-pedogenesis of carbonate rocks.     

Petrology,geochemistry and source characteristics of the Burpala alkaline massif,North Baikal

The Burpala alkaline massif contains rocks with more than 50 minerals rich in Zr,Nb,Ti,Th,Be and rare earth elements(REE).The rocks vary in composition from shonkinite,melanocratic syenite,nepheline and alkali syenites to alaskite and alkali granite and contain up to 10%LILE and HSFE,3.6%of REE and varying amounts of other trace elements(4%Zr,0.5%Y,0.5%Nb,0.5%Th and 0.1%U).Geological and geochemical data suggest that all the rocks in the Burpala massif were derived from alkaline magma enriched in rare earth elements.The extreme products of magma fractionation are REE rich pegmatites,apatite-fiuorite bearing rocks and carbonatites.The Sr and Nd isotope data suggest that the source of primary melt is enriched mantle(EM-Ⅱ).We correlate the massif to mantle plume impact on the active margin of the Siberian continent.     

Trace Elements and Rare Earth Elements of Sulfide Minerals in the Tianqiao Pb-Zn Ore Deposit, Guizhou Province, China

Trace elements and rare earth elements (REE) of the sulfide minerals were determined by inductively-coupled plasma mass spectrometry. The results indicate that V, Cu, Sn, Ga, Cd, In, and Se are concentrated in sphalerite, Sb, As, Ge, and Tl are concentrated in galena, and almost all trace elements in pyrite are low. The Ga and Cd contents in the light-yellow sphalerites are higher than that in the brown and the black sphalerites. The contents of Ge, Tl, In, and Se in brown sphalerites are higher than that in light-yellow sphalerites and black sphalerites. It shows that REE concentrations are higher in pyrite than in sphalerite, and galena. In sphalerites, the REE concentration decreases from light-yellow sphalerites, brown sphalerites, to black sphalerites. The ratios of Ga/In are more than 10, and Co/Ni are less than 1 in the studied sphalerites and pyrites, respectively, indicating that the genesis of the Tianqiao Pb–Zn ore deposit might belong to sedimentary-reformed genesis associated with hydrothermal genesis. The relationship between LnGa and LnIn in sphalerite, and between LnBi and LnSb in galena, indicates that the Tianqiao Pb–Zn ore deposit might belong to sedimentary-reformed genesis. Based on the chondrite-normalized REE patterns, δEu is a negative anomaly (0.13–0.88), and δCe does not show obvious anomaly (0.88–1.31); all the samples have low total REE concentrations (<3 ppm) and a wide range of light rare earth element/high rare earth element ratios (1.12–12.35). These results indicate that the ore-forming fluids occur under a reducing environment. Comparison REE compositions and parameters of sphalerites, galenas, pyrites, ores, altered dolostone rocks, strata carbonates, and the pyrite from Lower Carboniferous Datang Formation showed that the ore-forming fluids might come from polycomponent systems, that is, different chronostratigraphic units could make an important contribution to the ore-forming fluids. Combined with the tectonic setting and previous isotopic geochemistry evidence, we conclude that the ore-deposit genesis is hydrothermal, sedimentary reformed, with multisources characteristics of ore-forming fluids.     

REE Geochemistry of Loess in Xinjiang ,China

The total rare-earth element values(ΣREE)of loess in the Xinjiang region vary over a range of 128-200 ppm ,with an average of 153ppm .The average REE content of loess lies between the earth‘s crust (155ppm) and sedimentary rocks(151ppm).The Xinjiang loess,with the REE distribu-tion patterns characterized by negative slopes ,is rich in the Ce-family elements, and has a distribu-tion pattern characteristic of sedimentary rocks.The North Xinjiang loess is relatively depleted in Tb,but rich in Yb and Lu.The South Xinjiang loess is relatively rich in light rare-earth elements.This is full proof that the Xinjiang loess comes partly from weathered materials(clay rock,sandstone)in the region studied.The REE distribution patterns in the Xinjiang loess are similar to those in the precipitated dust and Aeolian sand,indicating the same material source.The REE distribution pat-terns in the Xinjiang loess are also similar to those in loess from the middle Yellow River Valley,China and Taskent,the former USSR.This implies that loesses of the three locations(Xinjiang,the mid-dle Yellow River Valley and Taskent) come from a common material source.But the REE patterns in the Xinjiang loess are different from those in wall rocks (volcanic rock,K-bearing volcanic rock).Generally ,LREE/HREE,Eu/Eu* and Ce/Ce* ratios reflect the features of parent materials of loess,indicating that the parent rocks were probably in the early stage of alkaline weathering and the weathered materials existed in an oxidation environment with basic mediums under arid-climatic conditions before transport.As a result,the migration ability of the REE is weak.     

清镇陨石（EH3）硫镁矿微量元素化学特征

本文应用电子探针和中子活化分析方法详细研究了清镇陨石(EH 3)中硫镁矿的化学组成和微量元素分布、硫镁矿携带了部分HREE、高度富集钪等难熔亲石元素,论证了该矿物的高温成因,REE丰度可能与陨硫钙石互补。该矿物含有钠-硒组分,可能是顽火辉石陨石独有的组分。铬归一化的钠-钴(原子比)相关关系具有CI一致的趋势,表明其母体来自太阳组成的气体星云。     

Diopside-bearing EL6 EET 90102: insights from rare earth element distributions

EET 90102 is the first known diopside-bearing EL6 chondrite. Diopside occurs in most aubrites and is occasionally found as rare small grains in unequilibrated enstatite chondrites, but is unknown from equilibrated enstatite chondrites. We have carried out a study of the rare earth element (REE) distributions in EET 90102, with a specific emphasis on diopside, in order to better understand its origin in this meteorite. We also present data for Ca-rich pyroxenes from two unequilibrated (EH3) enstatite chondrites for comparison.Our data show that diopside and other silicates in EET 90102 exhibit volatility-related anomalies indicative of formation under highly reducing conditions. Such anomalies have not previously been observed in EL6 chondrites, although they are common in unequilibrated enstatite chondrites. Diopside in EET 90102 probably formed by metamorphic equilibration of enstatite and oldhamite. The REE compositions of some grains, in particular the presence of positive Yb anomalies, indicate that they inherited their REE characteristics largely from CaS. Other grains have REE patterns that are more consistent with a derivation of diopside primarily from enstatite.In contrast to other EL6 chondrites, which experienced slow cooling, EET 90102 was quenched from high metamorphic temperatures. Thus, there may have been insufficient time to completely homogenize diopside REE compositions.The presence of diopside in EET 90102 simplifies one outstanding problem of aubrite formation. Melting of a diopside-bearing enstatite chondrite protolith provides a source for the abundant diopside in aubrites without requiring the oxidation of oldhamite, as suggested by previous research.     

REE and actinide microdistribution in Sahara 97072 and ALHA77295 EH3 chondrites: A combined cosmochemical and petrologic investigation

We report the results of rare earth elements (REEs) and U-Th inventory of individual minerals (oldhamite, enstatite and niningerite) in two of the most unequilibrated and primitive EH3 known so far, ALHA77295 and Sahara 97072. Under the highly reducing condition that prevailed during the formation of enstatite chondrites, REEs are mainly chalcophile and concentrated in oldhamite. The study is guided by detailed petrographic investigations of the individual minerals in chondrules, complex sulfide-metal clasts and enstatite-dominated matrices.We developed two textural parameters in order to resolve the evolution of oldhamite condensates and their residence in the solar gas prior to their accretion in the individual objects or in matrices and relate these textural features to the measured REE patterns of the individual oldhamite crystals. These textural parameters are the crystal habit of oldhamite grains (idiomorphic or anhedral) and their host assemblages. REE concentrations were measured by SIMS and LA-ICPMS.Oldhamite grains display REE enrichments (10-100 × CI). Four types of REE patterns are encountered in oldhamite in ALHA77295. In general the REE distributions cannot be assigned to a specific oldhamite-bearing assemblage. The most represented REE pattern is characterized by both slight to large positive Eu and Yb anomalies and is enriched in light REEs relative to heavy REEs. This pattern is present in 97% of oldhamite in Sahara 97072, suggesting a different source region in the reduced part of the nebula or different parental EH asteroids for the two EH3 chondrites. Different parental asteroids are also supported by MgS-FeS zoning profiles in niningerite grains adjacent to troilite revealing both normal and reverse zoning trends and different MnS contents. The observed homogeneity of REE distribution in oldhamite grains in Sahara 97072 is not related to the mild metamorphic event identified in this meteorite that caused breakdown of the major K- and Rb-bearing sulfide (djerfisherite).REE concentrations in enstatite range between 0.2 and 8 × CI. Hence, enstatite is an important REE host next to oldhamite. Most patterns are characterized by negative Eu and Yb anomalies. Niningerites are negligible contributors to bulk EH3 REE inventory. Average positive Eu and Yb anomalies observed in most oldhamite are complimentary to the negative ones in enstatite thus explaining the flat patterns of the bulk meteorites. The condensation calculations based on cosmic abundances predict that the first oldhamite condensates should have flat REE patterns with Eu and Yb depletions since Eu and Yb condense at lower temperature than other REE. However, this pattern is seen in enstatite. Our findings are at odds with the predicted negative Eu and Yb anomalies in oldhamite earliest condensates from a closed system in a reduced solar source. Our petrographic, mineral chemistry and REE abundances of oldhamite, enstatite and niningerite discards an origin of oldhamite by impact melting (Rubin et al., 2009).Our results do not support in first order the scenario of the incorporation of REE in the Earth’s core to explain ¹⁴²Nd excess in terrestrial samples relative to chondrites because oldhamite is the major REE carrier phase and has super-chondritic Sm/Nd ratios.     

Enrichment processes at the base of the Archean lithospheric mantle: observations from trace element characteristics of pyropic garnet inclusions in diamonds

Trace element concentrations of peridotitic garnet inclusions in diamonds from two Chinese kimberlite pipes were determined using the ion microprobe. Garnet xenocrysts from the same two kimberlite pipes were also analyzed for comparison. In contrast to their extremely refractory major element compositions, all harzburgitic garnets showed enrichment in light rare earth elements (REE) relative to chondrite, resulting in sinuous REE patterns. Both normal and sinuous REE patterns were observed from the lherzolitic garnets. Concentrations of REE in garnets changed significantly from diamond to diamond and no specific correlations were observed with their major element compositions. Analyses of randomly selected two to three points within every grain of a large number of garnet inclusions by the ion microprobe demonstrated that there was no evident compositional heterogeneity, and multiple grains of one phase from a single diamond host also exhibit very similar compositions. This implies that the trace element heterogeneity within one grain or among multiple inclusions from the same diamond host, as reported from Siberian diamonds, is not a common feature for these Chinese diamonds. Concentrations of Na, Ti, and Zr tend to decrease when garnets become more refractory, but variations of Sr and Li are more complex. Compositions rich in light REE and relatively poor in high field strength elements (HFSE) of the harzburgitic garnet inclusions in diamonds are generally consistent with metasomatism by carbonatite melts. The trace element features observed from the garnet inclusions in Chinese diamonds may be caused by carbonatite melt infiltration and partial melt extraction. Spatial and temporal gradients in melt/rock ratio and temperature are the main reasons for the large variations of REE patterns and other trace element concentrations. Received: 27 April 1999 / Accepted: 1 March 2000     

Chemical fractionations in meteorites—X. Ureilites

Four ureilites (Dyalpur, Goalpara, Haverö, and Novo Urei) were analyzed by radiochemical neutron activation analysis for Ag, Au, Bi, Br, Cd, Cs, Ge, In, Ir, Ni, Rb, Re, Sb, Se, Te, Tl, and U. An attempt has been made to resolve the data into contributions from the parent ultramafic rock and the injected, carbon- and gas-rich vein material. Interelement correlations, supported by analyses of separated vein material (WANKE et al, 1972), suggest that the vein material is enriched about 10-fold in refractory Ir and Re over moderately volatile Ni and Au, and is low in volatiles except Ge, C, and noble gases. It appears to be a refractory-rich nebular condensate that precipitated carbon by surface catalytic reactions at ˜500K and trapped noble gases but few other volatiles. The closest known analogue is a Cr- and C-rich fraction from the Allende meteorite, highly enriched in heavy noble gases and noble metals. By analogy with Allende, the gas-bearing phase in ureilites may have been an Fe, Cr-sulfide.

The ultramafic rock contains siderophiles and chalcophiles (Ni, Au, Ge, S, Se) at ˜0.05 of Cl chondrite level, and highly volatile elements (Rb, Cs, Bi, Tl, Br, Te, In, Cd) at ˜0.01 Cl level. It probably represents the residue from partial melting of a C3V-like chondrite body, under conditions where phase separation was incomplete so that some liquid was retained. The vein material was injected into this rock at some later time.     

Formation of metal in Grosvenor Mountains 95551 and comparison to ordinary chondrites

Siderophile element abundances in individual metal grains in the ungrouped chondrite Grosvenor Mountains (GRO) 95551 and in the ordinary chondrites Tieschitz H3.6, Soko-Banja LL4, and Allegan H5 were measured with laser ablation-inductively coupled plasma mass spectrometry. Matrix metal in GRO 95551 falls into two distinct compositional groups, a high-Ni group with 7.2 ± 0.4 wt% Ni and a low-Ni group with 3.7 ± 0.1 wt% Ni, indicating that kamacite/taenite equilibration at ∼1020 K was followed by rapid cooling. The nonrefractory siderophile elements P, Co, Cu, Ga, Ge, As, Pd, and Au also partition between the high-Ni and low-Ni metal in a manner consistent with kamacite/taenite fractionation, but the refractory siderophiles Ru, Re, Os, Ir, and Pt show correlated variations that are unrelated to kamacite/taenite partitioning and indicate that variations in refractory components of the metal were not completely erased during equilibration at ∼1020 K. The Ni-normalized bulk metal composition of GRO 95551 is refractory depleted and volatile rich relative to Bencubbin and related metal-rich chondrites but bears strong similarities to equilibrated ordinary chondrite metal. GRO 95551 represents a new chondrite type with chemical affinity to the ordinary chondrites. Individual metal grains in unequlibrated ordinary chondrites also have correlated variations in refractory siderophile contents that cannot be produced by redox processes alone; these variations span three orders of magnitude and diminish with increasing metamorphic grade of the ordinary chondrites.     

Mantle metasomatism—precursor to continental alkaline volcanism

REE distributions of an unusual suite of mantle-derived amphibole/apatite rich xenoliths have very steep, LREE-enriched chondrite-normalised patterns with no Eu anomalies. These are closely analogous to REE distributions of carbonatitic and kimberlitic rocks. A wide range in absolute abundances of REE reflects the varied mineral assemblages of this xenolith suite and, together with other trace element and volatile concentrations, supports an origin by fractionation of, or separation from, a volatile-charged LIL-enriched (possibly kimberlitic/carbonatitic) magma. Such a magma could be a medium for volatile transfer, addition of Ti, V, K and P, and LREE enrichment within the upper mantle. It is postulated that such metasomatism in the upper mantle is a necessary precursor to continental alkaline volcanism.Geochemical modelling based on REE suggests that a pyrolite source +0.35% apatite (total of 0.5% apatite), with amphibole accounting for all K₂O, can yield basanitic liquids with approximately 1–10% partial melting if the source is LREE-enriched (La about 20 times chondrite and Yb about 4.5–5 times chondrite).REE and trace element contents of the host rocks indicate that little exchange of these elements has occurred between xenolith and host magma during transport and emplacement.     

Are C1 chondrites chemically fractionated? a trace element study

Six C1 chondrite samples and a C2 xenolith from the Plainview H5 chondrite were analyzed by radiochemical neutron activation for the elements Ag, Au, Bi, Br, Cd, Ce, Cs, Eu, Ge, In, Ir, Lu, Nd, Ni, Os, Pd, Pt, Rb, Re, Sb, Se, Sn, Tb, Te, Tl, Yb, and Zn. The data were combined with 9 earlier analyses from this laboratory and examined for evidence of chemical fractionation in C1 chondrites.A number of elements (Br, Rb, Cs, Au, Re, Os, Ni, Pd, Sb, Bi, In, Te) show small but correlated variations. Those of the first 8 probably reflect hydrothermal alteration in the meteorite parent body, whereas those of Sb, Bi, In, and Te may at least in part involve nebular processes. Br and Au show systematic abundance differences from meteorite to meteorite, which suggests hydrothermal transport on a kilometer scale. The remaining elements vary from sample to sample, suggesting transport on a centimeter scale.There is no conclusive evidence for nebular fractionation affecting C1 's. Though C1 chondrites have lower $\text{Zr}\text{Hf}$ and $\text{Ir}\text{Re}$ ratios than do other chondrite classes, these ratios vary in other classes, suggesting that those classes rather than C1's are fractionated. Three fractionation-prone REE—Ce, Eu, and Yb have essentially the same relative abundances in C1's and all other chondrite classes, and hence apparently are not fractionated in C1's. We did not confirm the large Tb and Yb variations in C1's reported by other workers.We present revised mean C1 abundances for 35 elements, based on the new data and a critical selection of literature data. Changes are generally less than 10%, except for Br, Rb, Ag, Sb, Te, Au, and the REE.The Plainview C2 xenolith has normal trace element abundances, except for 3 elements falling appreciably above the C2 range: Rb, Cs, and Bi. Hydrothermal alteration may be the reason for all 3, though nebular fractionation remains a possibility for Bi.