Shallow burial dolomitisation of Middle–Upper Permian paleosols in an extensional tectonic context (SE Iberian Basin, Spain): Controls on temperature of precipitation and source of fluids

This work is focused on carbonate paleosols developed in three stratigraphic sections (Landete, Talayuelas and Henarejos) of theMiddle–Late Permian Alcotas Formation in the SE Iberian Basin. The Alcotas Formation, of alluvial origin, was deposited in semi-connected half-grabens developed during the early stages of the Permian–Triassic rifting stage that affected the Iberian Basin. The studied sections were located in two of these half-grabens, the Henarejos section being much closer to the basin boundary fault than the other two sections. The mineralogy and texture of the carbonate precursor of paleosols in the three studied sections are not preserved because original carbonate is replaced by coarse crystals of dolomite and/or magnesite. Dolomite crystals are typically euhedral, displaying rhombohedral shapes and reddish luminescence, although in the Henarejos section dolomite displays non-planar boundaries and frequently saddle habit. Micas are deformed and adapted to dolomite crystals, which, in turn, are affected by stylolites, suggesting that dolomite precipitated before mechanical and chemical compaction. Carbon and oxygen isotopic compositions of dolomite fromthe three sections showdifferent values (δ13CVPDB mean values=−6.7‰,−5.5‰ and −7.5‰; δ18OVPDB mean values=−4.0‰; –5.6‰and−8.2‰, at Landete, Talayuelas and Henarejos sections, respectively). The 87Sr/86Sr ratios are similar in the three sections yielding values between 0.71391 and 0.72213. The petrographic and geochemical features of dolomite in the three studied sections suggest precipitation fromsimilar fluids and during shallow burial diagenesis. Assuming that theminimum temperature for dolomite precipitation in the Henarejos sectionwas 60 °C (as suggested by the presence of non-planar saddle habit), and that the dolomitizing fluid had similar δ18O values at the three localities, then dolomite in the Talayuelas and Landete sections precipitated at temperatures around 16 and 25 °C cooler, respectively. In addition, the δ18OVSMOW values of the water from which dolomite precipitated would have ranged between −0.3 and −2.9‰. Dolomite is partially or totally replaced by non- to dark dull luminescent magnesite in the Landete and Talayuelas sections. Magnesite crystals are affected by stylolites, indicating that it precipitated before chemical compaction. The δ13C mean values are −6.5 and −6.0‰ and the δ18OVPDB mean values are −6.7 and −7.8‰, in the Landete and Talayuelas sections, respectively. The 87Sr/86Sr ratios of magnesite are similar in both sections yielding values between 0.71258 and 0.72508. This suggests that they probably precipitated from similar fluids during progressive burial and at higher temperatures than dolomites at the same sections. Assuming thatmagnesite precipitated froma fluid with similar δ18O values in both sections, then it had to precipitate at a temperature around 8 °C higher in Talayuelas than in the Landete section. Dolomitisation and magnesite precipitation probably occurred via reflux of saline to hypersaline brines from the overlying Mid-Late Triassic Muschelkalk and/or Keuper facies. The temperatures inferred for dolomite precipitation, however, are too high for shallow burial if a normal geothermal gradient is applied. Thus, it can be inferred that salinefluidswere heated as theyflowed through the syn-sedimentary extensional faults that controlledMiddle Permian to Middle Triassic sedimentation; consequently fluidswould have been at higher temperatures near the Henarejos area, which was closer to the basin boundary fault than at the Talayuelas and Landete areas, whichwere situated further away. This contention is in agreement with recent studies which demonstrate that an important thermal event took place during Late Triassic–Early Jurassic times in the Iberian Peninsula

Schoolchildren and one of the most unpopular animals: are they ready to protect snakes?

For cultural reasons and due to the narrow vision of environmental policy makers, most conservation efforts focus on a few charismatic species and consequently neglect the ma- jority of others under threat; many unpopular species are even killed in large numbers with little con- cern. Redressing this bias through educational programs is therefore important. Snakes are unpopular animals; they suffer from human harassment in most places and many populations have declined worldwide. Consequently, they provide suitable substrate to better improve conservation education in schoolchildren. Responses to a questionnaire administered to 2,570 schoolchildren (7–14 years old) from 10 countries showed that many children liked snakes and that most of the students wanted to see snakes protected. Such counterintuitive results were supported by the explanations given by the children, notably the reasons they liked or disliked snakes. Previous physical contact with snakes was often associated with snake likeability. We also found strong and expected differences between countries: for instance, where venomous snakes represented a health risk, most children declared to be afraid of snakes. Overall, our results negate the simplistic, and previously unverified, adult view that snakes are necessarily perceived as frightening animals, thereby justifying their persecution. This study provides an encouraging message, suggesting that it is not compulsory to focus on charismatic animals to convince children to protect wildlife