Zirconolite, zircon and monazite-(Ce) U-Th-Pb age constraints on the emplacement, deformation and alteration history of the Cummins Range Carbonatite Complex, Halls Creek Orogen, Kimberley region, Western Australia

In situ SHRIMP U-Pb dating of zirconolite in clinopyroxenite from the Cummins Range Carbonatite Complex, situated in the southern Halls Creek Orogen, Kimberley region, Western Australia, has provided a reliable 207Pb/206Pb age of emplacement of 1009 ± 16 Ma. Variably metamict and recrystallised zircons from co-magmatic carbonatites, including a megacryst ~1.5 cm long, gave a range of ages from ~1043–998 Ma, reflecting partial isotopic resetting during post-emplacement deformation and alteration. Monazite-(Ce) in a strongly foliated dolomite carbonatite produced U-Th-Pb dates ranging from ~900–590 Ma. Although the monazite-(Ce) data cannot give any definitive ages, they clearly reflect a long history of hydrothermal alteration/recrystallisation, over at least 300 million years. This is consistent with the apparent resetting of the Rb-Sr and K-Ar isotopic systems by a post-emplacement thermal event at ~900 Ma during the intracratonic Yampi Orogeny. The emplacement of the Cummins Range Carbonatite Complex probably resulted from the reactivation of a deep crustal structure within the Halls Creek Orogen during the amalgamation of Proterozoic Australia with Rodinia over the period ~1000–950 Ma. This may have allowed an alkaline carbonated silicate magma that was parental to the Cummins Range carbonatites, and generated by redox and/or decompression partial melting of the asthenospheric mantle, to ascend from the base of the continental lithosphere along the lithospheric discontinuity constituted by the southern edge of the Halls Creek Orogen. There is no evidence of a link between the emplacement of the Cummins Range Carbonatite Complex and mafic large igneous province magmatism indicative of mantle plume activity. Rather, patterns of Proterozoic alkaline magmatism in the Kimberley Craton may have been controlled by changing plate motions during the Nuna–Rodinia supercontinent cycles (~1200–800 Ma)

Levels of carcinoembryonic antigen and CA 19-9 in the sera and peritoneal washing of patients undergoing surgical treatment for gastric carcinoma Níveis do antígeno carcinoembriônico e do CA 19-9 no soro e no lavado peritonial em doentes submetidos ao tratamento cirúrgico do carcinoma gástrico

BACKGROUND: Early peritoneal recurrence of gastric carcinoma following curative resection remains a great challenge in the treatment and prevention of this disease. AIM: To analyze the relationship between levels of tumor markers, carcinoembryonic antigen (CEA) and CA 19-9 in the sera and peritoneal washing, and anatomopathological aspects of the gastric carcinoma. METHODS: Of the 46 patients in the study, 29 (63.0%) were males and 17 (37.0%) females. Mean age was 63.6 ± 11.7 years (31 to 91 years). Peripheral venous blood samples were collected from the upper limb vein from both patient groups after anesthetic induction, in order to determine serum levels of CEA and CA 19-9. After the end of the procedure, 50 mL of physiologic solution was introduced into the bottom of the Douglas sack and a portion aspirated to determine CEA and CA 19-9 levels in the peritoneal washing. Levels of CEA and CA 19-9 in the sera and peritoneal washing were compared to the following variables: lesion diameter &#8804;4 cm or >4 cm, lymph node involvement, angiolymphatic invasion, depth of invasion into gastric wall, and initial or late stage. RESULTS: Sera CEA levels were significantly higher in patients with lesions >5 cm. CEA levels in the sera and peritoneal washing were significantly greater in patients with signet ring cell gastric carcinoma. In addition, levels of CEA in peripheral blood and peritoneal washing showed significant association with the degree of carcinoma penetration into the gastric wall, while sera CEA was significantly higher in patients at more advanced stages. There was no significant difference between sera and peritoneal CEA values regarding grade of differentiation. Patients with gastric lesions measuring > 5cm and more differentiated lesions had significantly higher sera CA 19-9 values. In patients with lymph nodes invasion by gastric carcinoma, CA 19-9 levels in peritoneal washing were significantly higher than in peripheral blood. Levels of CA 19-9 in peritoneal washing were significantly greater at advanced stages than the initial stage of the gastric carcinoma. CONCLUSIONS: Elevated levels of CA 19-9 in peritoneal washing were significantly associated with more advance stages of gastric carcinoma and was more reliable predictive factor for staging than sera CA 19-9 levels. CEA levels in the sera more accurately reflected neoplasia stage than levels in peritoneal washing.<br>RACIONAL: A recidiva peritonial precoce do carcinoma gástrico operado com intenção curativa continua sendo um grande desafio do seu tratamento e prevenção. OBJETIVO: Analisar a relação entre os níveis do marcador tumoral antígeno carcinoembriônico (CEA) e CA 19-9 no sangue e no lavado peritonial e os aspectos anatomopatológicos do carcinoma gástrico. MÉTODO: Dos 46 doentes do estudo, 29 (63,0%) eram do sexo masculino e 17 (37,0%) do feminino. A média de idade foi de 63,6 ± 11,7 anos (31 a 91 anos). Após a indução anestésica, o sangue venoso periférico foi coletado de veia do membro superior para a determinação do nível sérico do CEA e CA 19-9. Após o término do procedimento operatório foram derramados 50 mL de solução fisiológica no fundo de saco de Douglas, aspirada alíquota que foi encaminhada para a determinação do nível no lavado peritonial do CEA e CA 19-9. O nível do CEA e do CA 19-9 sérico e no lavado peritonial foram relacionados às seguintes variáveis: diâmetro da lesão &#8804;4 cm ou >4 cm, comprometimento linfonodal, invasão angiolifática, profundidade de invasão na parede gástrica e estádio inicial ou tardio. RESULTADOS: Em relação ao CEA, o nível sérico foi significantemente maior nos doentes com o diâmetro da lesão >5 cm. O nível de CEA sérico e no lavado peritonial foi significantemente maior nos doentes com carcinoma gástrico com células em anel de sinete. O nível de CEA no sangue periférico e no lavado peritonial mostrou relação significante com o nível de penetração do carcinoma na parede gástrica, e o CEA sérico foi significantemente mais elevado nos doentes com estádio mais avançados. Não houve diferença significante entre os valores do CEA sérico e peritonial nos carcinomas mais diferenciados em relação aos menos diferenciados. No tocante ao CA 19-9, os enfermos com lesões gástricas com diâmetro >5 cm e mais diferenciadas exibiram valores séricos de CA 19-9 significantemente maiores. Nos doentes com linfonodos comprometidos pelo carcinoma gástrico, os níveis de CA 19-9 no lavado peritonial foram significantemente maiores do que os no sangue periférico. Níveis do CA 19-9 no lavado peritonial foram significantemente maiores no estádio avançado em relação ao estádio inicial do carcinoma gástrico. CONCLUSÕES: Níveis elevados do CA 19-9 no lavado peritonial foi significantemente associado com estádios mais avançados do carcinoma gástrico e foi fator preditivo mais fidedigno para o estádio do que os níveis séricos do CA 19-9. Os níveis séricos do CEA refletiram mais acuradamente o estádio da neoplasia do que os níveis no lavado peritonial

The Yungul carbonatite dykes associated with the epithermal fluorite deposit at Speewah, Kimberley, Australia: carbon and oxygen isotope constraints on their origin

The Yungul carbonatite dykes at Speewah in the Kimberley region of Western Australia were emplaced along a north-trending splay from the northeast-trending Greenvale Fault located at the western boundary of the Halls Creek Orogen. The Yungul carbonatite dykes intrude a thick composite sill of the Palaeoproterozoic Hart Dolerite (~1,790 Ma), consisting of tholeiitic dolerite and gabbro with its felsic differentiates that form the Yilingbun granophyres and associated granites. The carbonatite dykes consist of massive, calcite carbonatite that host very coarse, pegmatitic veins and pods of calcite, and have largely replaced (carbonatitized) and fenitized the country rock Hart Dolerite suite in a zone up to 150 m wide. Dykes of red-brown siliceous fluidized-breccia and epithermal-textured veins consisting of bladed quartz, adularia and fluorite are closely associated with the carbonatite dykes. The Yungul carbonatites are closely associated with fluorite occurrences with resources currently reported as 6.7 Mt at 24.6% CaF2. The precise age of the Yungul carbonatite is not known, although it is believed to be post early Cambrian. The total REE content of the Yungul carbonatite is low (174.0–492.8 ppm; La/Yb 2.28–10.74) and thus atypical for calciocarbonatite. Chondrite-normalized REE patterns for the carbonatite are relatively flat compared to average calciocarbonatite, and show small negative Eu anomalies. These unusual geochemical features may have been acquired from the Hart Dolerite suite during emplacement of the carbonatite, a process that involved extensive replacement and fenitization of country rocks. Carbon and oxygen isotope compositions of massive calcite carbonatite and the coarse calcite veins and pods from the carbonatite suggest a deep-seated origin. The C and O isotope compositions show an overall positive correlation that can be attributed to both magmatic and magmatic-hydrothermal processes in their evolution. The magmatic δ13C-δ18O trend is also indicative of crustal contamination and/or low-temperature water/rock exchange. The carbon isotopic compositions have δ13C values that range from about −5.2‰ to −6.3‰ that support a mantle-derived origin for the Yungul carbonatites and are consistent with earlier conclusions based on whole-rock geochemistry and radiogenic isotopes studies