Mineralogy and Petrology of EK-459-5-1, A Type B1 CAI from Allende

Calcium-aluminum-rich inclusions (CAIs) are a type of coarse-grained clast composed of Ca-, Al-, and Mg-rich silicates and oxides found in chondrite meteorites. Type B (CAIs) are exclusively found in the CV chondrite meteorites and are the most well studied type of inclusion found in chondritic meteorites. Type B1 CAIs are distinguished by a nearly monomineralic rim of melilite that surrounds an interior predominantly composed of melilite, fassaite (Ti and Al-rich clinopyroxene), anorthite, and spinel with varying amounts of other minor primary and secondary phases. The formation of Type B CAIs has received considerable attention in the course of CAI research and quantitative models, experimental results and observations from Type B inclusions remain largely in disagreement. Recent experimental results and quantitative models have shown that the formation of B1 mantles could have occurred by the evaporative loss of Si and Mg during the crystallization of these objects. However, comparative studies suggest that the lower bulk SiO2 compositions in B1s result in more prior melilite crystallization before the onset of fassaite and anorthite crystallization leading to the formation of thick melilite rich rims in B1 inclusions. Detailed petrographic and cosmochemical studies of these inclusions will further our understanding of these complex objects

In Situ Trace Element Analysis of an Allende Type B1 CAI: EK-459-5-1

Variations in refractory major and trace element composition of calcium, aluminum-rich inclusions (CAIs) provide constraints on physical and chemical conditions and processes in the earliest stages of the Solar System. Previous work indicates that CAIs have experienced complex histories involving, in many cases, multiple episodes of condensation, evaporation, and partial melting. We have analyzed major and trace element abundances in two core to rim transects of the melilite mantle as well as interior major phases of a Type B1 CAI (EK-459-5-1) from Allende by electron probe micro-analyzer (EPMA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to investigate the behavior of key trace elements with a primary focus on the REEs Tm and Yb

Al-Mg Isotope Study of Allende 5241

The defining characteristic of type B1 CAIs is a large (.5- 3mm) concentric melilite mantle [1]. In [2] we presented two isochrons from separate traverses across the melilite mantle of Allende EK 459-5-1. The primary petrographic differences between the traverses was the preservation of strong oscillatory zoning. The traverse that crossed the distinctive oscillatory zone produced a pristine internal isochron, while the other that did not have a strongly preserved oscillatory zone produced a disturbed isochron indicated by more scatter (higher MSWD) and a positive (delta)26Mg* intercept. The implication simply being that the oscillatory zone may represent varying conditions during the mantle formation event. We targeted a similar texture in Allende 5241 using the same methodology in an attempt to achieve similar results

Stable Magnesium Isotope Variation in Melilite Mantle of Allende Type B1 CAI EK 459-5-1

Ca-Al-rich inclusions (CAIs) are the earliest formed crystalline material in our solar system and they record early Solar System processes. Here we present petrographic and delta Mg-25 data of melilite mantles in a Type B1 CAI that records early solar nebular processes

New Petrology, Mineral Chemistry and Stable MG Isotope Compositions of an Allende CAI: EK-459-7-2

Calcium-aluminum-rich inclusions (CAIs) are the key to understanding physical and chemical conditions in the nascent solar nebula. These inclusions have the oldest radiometric ages of solar system materials and are composed of phases that are predicted to condense early from a gas of solar composition. Thus, their chemistry and textures record conditions and processes in the earliest stages of development of the solar nebula. Type B inclusions are typically larger and more coarse grained than other types with substantial evidence that many of them were at least partially molten. Type B inclusions are further subdivided into Type B1 (possess thick melilite mantle) and Type B2 (lack melilite mantle). Despite being extensively studied, the origin of the melilite mantles of Type B1 inclusions remains uncertain. We present petrologic and chemical data for a Type B inclusion, EK-459-7-2, that bears features found in both Type B1 and B2 inclusions and likely represents an intermediate between the two types. Detailed studies of more of these intermediate objects may help to constrain models for Type B1 rim formation

Development of the Reno Inventory of Self-Perspective

AbstractThree forms of self are described in Relational Frame Theory (RFT) and in the Acceptance and Commitment Therapy (ACT) models of psychological pathology or flexibility: self-as-content, self-as-process, and self-as-context. Treatment components of Acceptance and Commitment Therapy (ACT) target these aspects of self to reduce attachment to the first and foster the others. The present study developed a scale to measure self in the ACT models of psychological flexibility and pathology and evaluated its psychometric properties. The Reno Inventory of Self-Perspective (RISP) was tested during two phases in which separate samples were administered the RISP battery with well-established or theoretically related measures. Statistical and theoretical analyses were applied to identify potential models. During phase 1, a comprehensive approach was used to identify factors using parallel analysis, principal axis extraction, and promax rotation with two reduced versions of the initial battery, RISPBV43 (RISP Battery Version 43-items) and RISPBV22 (RISP Battery Version 22-items, subsumed by the 43-item version). Multiple structures were additionally tested with structural equation modeling in phase 1. This process led to two models of good fit to be confirmed and contrasted against each other with the Phase 2 sample. During phase 2, the competing models (17-item 2D-RISP and 13-item 3D-RISP) were examined. Both were confirmed to be reliable, valid, and of good fit. After additional comparative evaluation of their performance as predictors, the more parsimonious 3-dimensional RISP was selected. The 3D-RISP measures fusion with self-content (entangled), the ability to take a centered self-perspective (centered), and verbal awareness of the transcendent nature of that perspective (transcendent). The measure demonstrated good internal consistency in 2 large samples (α = .86 with N= 646 college sample; and α = .79 in the more diverse N=543 confirmatory sample). In both samples, the 3D-RISP consistently negatively correlated with psychological inflexibility, anxiety, and depression. The scale strongly related to coping self-efficacy in phase 1 and distress tolerance in phase 2

Supra-Canonical Initial 26Al/27Al from a Reprocessed Allende CAI

No abstract availabl

Mechanical adaptation of trabecular bone morphology in the mammalian mandible

Alveolar bone, together with the underlying trabecular bone, fulfils an important role in providing structural support against masticatory forces. Diseases such as osteoporosis or periodontitis cause alveolar bone resorption which weakens this structural support and is a major cause of tooth loss. However, the functional relationship between alveolar bone remodelling within the molar region and masticatory forces is not well understood. This study investigated this relationship by comparing mammalian species with different diets and functional loading (Felis catus, Cercocebus atys, Homo sapiens, Sus scrofa, Oryctolagus cuniculus, Ovis aries). We performed histomorphometric analyses of trabecular bone morphology (bone volume fraction, trabecular thickness and trabecular spacing) and quantified the variation of bone and tooth root volumes along the tooth row. A principal component analysis and non-parametric MANOVA showed statistically significant differences in trabecular bone morphology between species with contrasting functional loading, but these differences were not seen in sub-adult specimens. Our results support a strong, but complex link between masticatory function and trabecular bone morphology. Further understanding of a potential functional relationship could aid the diagnosis and treatment of mandibular diseases causing alveolar bone resorption, and guide the design and evaluation of dental implants