The link between volcanism and plutonism in epizonal magma systems; high-precision U–Pb zircon geochronology from the Organ Mountains caldera and batholith, New Mexico

The Organ Mountains caldera and batholith expose the volcanic and epizonal plutonic record of an Eocene caldera complex. The caldera and batholith are well exposed, and extensive previous mapping and geochemical analyses have suggested a clear link between the volcanic and plutonic sections, making this an ideal location to study magmatic processes associated with caldera volcanism. Here we present high-precision thermal ionization mass spectrometry U–Pb zircon dates from throughout the caldera and batholith, and use these dates to test and improve existing petrogenetic models. The new dates indicate that Eocene volcanic and plutonic rocks in the Organ Mountains formed from ~44 to 34 Ma. The three largest caldera-related tuff units yielded weighted mean [superscript 206]Pb/[superscript 238]U dates of 36.441 ± 0.020 Ma (Cueva Tuff), 36.259 ± 0.016 Ma (Achenback Park tuff), and 36.215 ± 0.016 Ma (Squaw Mountain tuff). An alkali feldspar granite, which is chemically similar to the erupted tuffs, yielded a synchronous weighted mean [superscript 206]Pb/[superscript 238]U date of 36.259 ± 0.021 Ma. Weighted mean [superscript 206]Pb/[superscript 238]U dates from the larger volume syenitic phase of the underlying Organ Needle pluton range from 36.130 ± 0.031 to 36.071 ± 0.012 Ma, and the youngest sample is 144 ± 20 to 188 ± 20 ka younger than the Squaw Mountain and Achenback Park tuffs, respectively. Younger plutonism in the batholith continued through at least 34.051 ± 0.029 Ma. We propose that the Achenback Park tuff, Squaw Mountain tuff, alkali feldspar granite and Organ Needle pluton formed from a single, long-lived magma chamber/mush zone. Early silicic magmas generated by partial melting of the lower crust rose to form an epizonal magma chamber. Underplating of the resulting mush zone led to partial melting and generation of a high-silica alkali feldspar granite cap, which erupted to form the tuffs. The deeper parts of the chamber underwent continued recharge and crystallization for 144 ± 20 ka after the final eruption. Calculated magmatic fluxes for the Organ Needle pluton range from 0.0006 to 0.0030 km3/year, in agreement with estimates from other well-studied plutons. The petrogenetic evolution proposed here may be common to many small-volume silicic volcanic systems

Wettability Switching Techniques on Superhydrophobic Surfaces

The wetting properties of superhydrophobic surfaces have generated worldwide research interest. A water drop on these surfaces forms a nearly perfect spherical pearl. Superhydrophobic materials hold considerable promise for potential applications ranging from self cleaning surfaces, completely water impermeable textiles to low cost energy displacement of liquids in lab-on-chip devices. However, the dynamic modification of the liquid droplets behavior and in particular of their wetting properties on these surfaces is still a challenging issue. In this review, after a brief overview on superhydrophobic states definition, the techniques leading to the modification of wettability behavior on superhydrophobic surfaces under specific conditions: optical, magnetic, mechanical, chemical, thermal are discussed. Finally, a focus on electrowetting is made from historical phenomenon pointed out some decades ago on classical planar hydrophobic surfaces to recent breakthrough obtained on superhydrophobic surfaces

Deducing the source and composition of rare earth mineralising fluids in carbonatites: insights from isotopic (C, O, 87Sr/86Sr) data from Kangankunde, Malawi

This is the final version of the article. Available from Springer Verlag via the DOI in this record.Carbonatites host some of the largest and highest grade rare earth element (REE) deposits but the composition and source of their REE-mineralising fluids remains enigmatic. Using C, O and 87Sr/86Sr isotope data together with major and trace element compositions for the REE-rich Kangankunde carbonatite (Malawi), we show that the commonly observed, dark brown, Fe-rich carbonatite that hosts REE minerals in many carbonatites is decoupled from the REE mineral assemblage. REE-rich ferroan dolomite carbonatites, containing 8–15 wt% REE2O3, comprise assemblages of monazite-(Ce), strontianite and baryte forming hexagonal pseudomorphs after probable burbankite. The 87Sr/86Sr values (0.70302–0.70307) affirm a carbonatitic origin for these pseudomorph-forming fluids. Carbon and oxygen isotope ratios of strontianite, representing the REE mineral assemblage, indicate equilibrium between these assemblages and a carbonatite-derived, deuteric fluid between 250 and 400 °C (δ18O + 3 to + 5‰VSMOW and δ13C − 3.5 to − 3.2‰VPDB). In contrast, dolomite in the same samples has similar δ13C values but much higher δ18O, corresponding to increasing degrees of exchange with low-temperature fluids (< 125 °C), causing exsolution of Fe oxides resulting in the dark colour of these rocks. REE-rich quartz rocks, which occur outside of the intrusion, have similar δ18O and 87Sr/86Sr to those of the main complex, indicating both are carbonatite-derived and, locally, REE mineralisation can extend up to 1.5 km away from the intrusion. Early, REE-poor apatite-bearing dolomite carbonatite (beforsite: δ18O + 7.7 to + 10.3‰ and δ13C −5.2 to −6.0‰; 87Sr/86Sr 0.70296–0.70298) is not directly linked with the REE mineralisation.This project was funded by the UK Natural Environment Research Council (NERC) SoS RARE project (NE/M011429/1) and by NIGL (NERC Isotope Geoscience Laboratory) Project number 20135

Holocene Cyclic Records of Ice-Rafted Debris and Sea Ice Variations on the East Greenland and Northwest Iceland Margins

The dynamics of the Greenland Ice Sheet and drift of sea ice from the Arctic Ocean reaching Denmark Strait are poorly constrained. We present data on the provenance of Fe oxide detrital grains from two cores in the Denmark Strait area and compare the Fe grain source data with other environmental proxies in order to document the variations and potential periodicities in ice-rafted debris delivery during the Holocene. Based on their Fe grain geochemistry, the sediments can be traced to East Greenland sources and to more distal sites around the Arctic Basin. On the Holocene time scales of the two cores, sea ice biomarker (IP25) data, and quartz weight percent reveal positive associations with T°C and inverse associations with biogenic carbonate wt%. Trends in the data were obtained from Singular Spectrum Analysis (SSA), and residuals were tested for cyclicity. Trends on the environmental proxies explained between 15 and 90% of the variance. At both sites the primary Fe grain sources were from Greenland, but significant contributions were also noted from Banks Island and Svalbard. There is a prominent cyclicity of 800 yrs as well as other less prominent cycles for both Greenland and arctic sources. The Fe grain sources from Greenland and the circum-Arctic Ocean are in synchronization, suggesting that the forcings for these cycles are regional and not local ice sheet instabilities

How do you track down rumors?

Many departments have found one or another form of sensitivity training a valuable if not indispensable method for training their students. In almost all cases, it is a powerful and effective tool, designed and used for the betterment in some way of its participants. Such sensitivity-training groups have been employed by some departments successfully at the undergraduate as well as graduate level. The outcomes have been sufficiently satisfactory so that many students are required to participate in groups as part of the educational process. The rumors are to the effect that other departments have encountered serious consequences of intensive sensitivity training for some participants, such that several departments had forbidden that its students engage in T grouping. "Hard" data would be, to put it mildly, hard to come by. But some rumors, especially when they relate to the relationship of the profession to the public, and of faculty members to their students, are disquieting to the degree that requires some investigation--at least an investigation that is sufficient to help us reach a decision whether there should be a full and adequately designed and controlled study. Result: An attempt, not to get precise data, but solely to determine whether there was any fire whatsoever under the smoke--to determine whether it is indeed smoke, or merely local fogging conditions; that is, to track down the rumors. Method: A letter of inquiry was sent to the chairman of all graduate departments that offer degrees in psychology--over 300 of them--with a postcard enabling response by check, and a request for comment and amplification in letters. The postcard tried to determine whether the department chairman had heard such rumors, whether his department had had "incidents," and whether he thought "we have no responsibility.

Burrhus F. Skinner

In dealing with Skinner, we are concerned with a theorist who now espouses no theory, a systematist whose system is still developing, and a constructive thinker some of whose most important contributions have been those of a critic. In the course of his writings, Skinner has presented the results of a comprehensive experimental program, and elaborated a theory of behavior based upon it. Since its publication in comprehensive form in The Behavior of Organisms, he has, one may infer from more recent writings, modified it greatly by eliminating several central concepts without substituting others. These publications are not sufficient to enable us to analyze the system in its current status, so that we will restrict ourselves to its earlier form. From an examination of this theory, we may learn something of the reasons for its alteration, and perhaps reveal some relationships between the adequacy of the theory as it was stated and the procedures which were followed in its construction. That portions of the theory as it was presented in 1938 no longer find complete acceptance is not relevant to our purpose; much may be learned from autopsies. The revision of Sinner's theoretical views has not extended downward to his basic assumptions with respect to the nature of psychological theory, nor to the elementary statements of much of his data language and of the basic laws of behavior. The systematic position is unchanged. It is largely at the level at which complex concepts are introduced that revisions have been made

The Egg Revealed

"Problem Solving" needs either a brief and summary appraisal or an extended one--too long for the space likely to be allotted. Written lucidly and persuasively, it demonstrates that Dr. Skinner can define and analyze a broad set of behaviors using a limited set of behavioral terms and concepts. Believers will find it convincing, even brilliant. Behaviorists who have worked on problem solving, who have observed their subjects carefully, and who have collected data analytically--especially those who have also labored to clarify the technical terminology of behaviorism operationally--will find it a good deal less than persuasive. Glib, superficial and misleading are more appropriate terms. Closely argued and exemplified points are followed by one liners, such as: "But to speak of the purpose of an act is simply to refer to its characteristic consequences." That cannot survive critical examination

Comparative psychology

This chapter was prepared following a series of visits to laboratories and field stations where comparative psychology is under very active investigation. What has been observed, taken with this year's publications in the psychological, ethological, and biological journals, and the chapters of previous Annual Reviews, has given the chapter its form. The advances in the past year in the topics usually allocated most space in this chapter, and that most psychologists think of when they think of comparative psychology at all have not been great. Some might have been advances if they had appeared when the experimental work was completed. Another paper provides a discussion of brain weights in more or less association with the report of some experiments on learning; the relation established is one of simple contiguity in the pages of a paper. Little new appears on hoarding; investigations of bird navigation seem to have reached an impasse, where the only theory that seems adequate to the facts is untenable. [For a popularized summary, see Carthy.] The quasi-monopoly of the experimental study of sex behavior in the male boojum, or rat, held by Beach and his colleagues, has been broken with the appearance of an excellent monograph by Larrson. The general picture is a familiar one: advances have occurred, but at glacial pace; work on familiar variables inches along. A different picture arises, however, if the work of ethologists and zoologists in the field of behavior is examined in its own context rather than according to psychologists' ideas of what should be important. Here the advances in the last year--in the last few years--have been rapid, remarkable, and of direct relevance to psychologists, whether comparative, experimental, social, or clinical. Ethologists, mostly European zoologists, study the behavior of a number of species from an objective (in the Watsonian or Pavlovian sense) point of view that does not exclude an active interest in physiological correlates of behavior. Previous chapters in this Annual Review will have familiarized the reader with some of their work, but they have placed, I think, undue stress on a few sets of investigations and misleadingly emphasized some now obsolete parts of ethological theorizing. What follows is based not only on the current publications of ethologists, but also on visits to their laboratories, and on many and long discussions with them