Description: Early diagenetic dolomite formation in methanogenic marine sediments is enigmatic because acidifi cation by CO2, a by-product of methanogenesis, should lead to carbonate dissolution and not precipitation. However, petrographic relationships indicate that dolomite breccia layers with δ13C values of ~+15‰, recovered from the lower slope of the Peru continental margin (Ocean Drilling Program Site 1230), formed deep in the methanogenic zone during tectonic activity of a décollement. Based on radiogenic Sr isotope ratios (87Sr/86Sr 〉 0.711) and positive δ18O values (+6‰), we present evidence that the dolomite breccias mainly formed from fl uids originating from deep sedimentary units within the accretionary prism, where they interacted with continental crust and/or siliciclastic rocks of continental affi nity. Due to silicate alteration and dehydration, such fl uids are likely alkaline and thus have the potential to neutralize the acidifi cation imposed by the high dissolved CO2 concentrations. This scenario provides a potential mechanism by which dolomite formation can be induced deep in a highly active methanogenic zone.

Description: In A.D. 1755, an earthquake destroyed Lisbon, Portugal. The region was then hit forcefully by a tsunami and engulfed by an enormous fire. Thefts and destruction followed, damaging emblematic places of irreplaceable historical and spiritual value, especially churches. The occurrence of the 1755 Lisbon earthquake remains known by the eldest, but it has been forgotten and even unheard of by younger generations. Over the last decade there has been a considerable increase in the research, involving geologists, seismologists, and oceanographers, so as to better understand the processes and the complexity of seismic risks and tsunamis. However, little has been done to inform the population and policy makers about the options available to them to better prevent and respond to earthquake disasters. The main aim of this study is to evaluate the Portuguese citizens’ scientific literacy regarding tsunamis and to analyze their knowledge related to the 1755 earthquake. For this purpose, we conducted 206 structured interviews in a public place, and asked the general public to collaborate. At the beginning of the interviews people were shown a previously drawn scenario showing a tsunami epicenter and three boats in different places of the ocean. The sample comprised 107 females (52%) and 99 males (48%) (ages ranged from 12 to 85). The interviews were conducted by two members of the research team and were audiotaped for a better and more reliable transcription. Content analysis was subsequently established with the help of the QSR International NVivo 10 qualitative data analysis software package ( www.qsrinternational.com/nvivo-product ). Results showed that there is a wide lack of knowledge regarding tsunamis, including those that occurred in the past, and the majority of interviewees recognized the need to know more about these issues. This evidence indicates the importance of including these historical and social and scientific issues in geosciences programs, giving more relevance to teaching seismic risks, their prevention, and possible responses.

Description: Here, we report the isolation of 31 Acinetobacter baumannii strains producing OXA-253 in a single large Brazilian city. These strains belonged to five different sequence types (STs), including 4 STs not previously associated with bla OXA-253 . In all strains, the bla OXA-253 gene was located in a plasmid within a genetic environment similar to what was found previously in Brazil and Italy. The reported data emphasize the successful transmission of the bla OXA-253 gene through a large area and the tendency for this resistance determinant to remain in the A. baumannii population.

Description: Dolomite is a very common carbonate mineral in ancient sediments, but is rarely found in modern environments. Because of the difficulties in precipitating dolomite in the laboratory at low temperatures, the controls on its formation are still debated after more than two centuries of research. Two important parameters to constrain the environment of dolomitization are the temperature of formation and the oxygen isotope composition of the fluid from which it precipitated. Carbonate clumped isotopes (expressed with the parameter Δ47) are increasingly becoming the method of choice to obtain this information. However, whereas many clumped isotope studies treated dolomites the same way as calcite, some recent studies observed a different phosphoric acid fractionation for Δ47 during acid digestion of dolomite compared to calcite. This causes additional uncertainties in the Δ47 temperature estimates for dolomites analyzed in different laboratories using different acid digestion temperatures. To tackle this problem we present here a (proto-)dolomite-specific Δ47-temperature calibration from 25 to 1100 °C for an acid reaction temperature of 70 °C and anchored to widely available calcite standards. For the temperature range 25 to 220 °C we obtain a linear Δ47-T relationship based on 289 individual measurements with R2 of 0.864: When including two isotopically scrambled dolomites at 1100 °C, the best fit is obtained with a third order polynomial temperature relationship (R2 = 0.924):‰ Applying a calcite Δ47-T relationship produced under identical laboratory conditions results in 3 to 16 °C colder calculated formation temperatures for dolomites (with formation temperature from 0 to 100 °C) than using the (proto-)dolomite specific calibration presented here. For the synthetic samples formed between 70 and 220 °C we also determined the temperature dependence of the oxygen isotope fractionation relative to the water. Based on the similarity between our results and two other recent studies (Vasconcelos et al., 2005 and Horita, 2014) we propose that a combination of the three datasets represents the most robust calibration for (proto-)dolomite formed in a wide temperature range from 25 to 350 °C. Because of the uncertainties in the phosphoric acid oxygen and clumped isotope fractionation for (proto-)dolomite, we promote the use of three samples that are available in large amounts as possible inter-laboratory reference material for oxygen and clumped isotope measurements. A sample of the middle Triassic San Salvatore dolomite from southern Switzerland, the NIST SRM 88b dolomite standard already reported in other Δ47 studies and a lacustrine Pliocene dolomite from La Roda (Spain). This study demonstrates the necessity to apply (proto-)dolomite specific Δ47-T relationships for accurate temperature estimates of dolomite formation, ideally done at identical acid digestion temperatures to avoid additional uncertainties introduced by acid digestion temperature corrections. In addition, the simultaneous analyses of dolomite reference material will enable a much better comparison of published dolomite clumped and oxygen isotope data amongst different laboratories.