Decompression during Late Proterozoic Al2SiO5 Triple-Point Metamorphism at Cerro Colorado, New Mexico

An outstanding problem in understanding the late Proterozoic tectonic assembly of the southwest is identifying the tectonic setting associated with regional metamorphism at 1.4 Ga. Both isobaric heating and cooling, and counter-clockwise looping PT paths are proposed for this time. We present a study of the Proterozoic metamorphic and deformation history of the Cerro Colorado area, southern Tusas Mountains, New Mexico, which shows that the metamorphism in this area records near-isothermal decompression from 6 to 4 kbar at ca. 1.4 Ga. We do not see evidence for isobaric heating at this time. Decompression from peak pressures is recorded by the reaction Ms + Grt = St + Bt, with a negative slope in PT space; the reaction Ms + Grt = Sil + Bt, which is nearly horizontal in PT space; and partial to total pseudomorphing of kyanite by sillimanite during the main phase of deformation. The clearest reaction texture indicating decompression near peak metamorphic temperature is the replacement of garnet by clots of sillimanite, which are surrounded by halos of biotite. The sillimanite clots, most without relict garnet in the cores and with highly variable aspect ratios, are aligned. They define a lineation that formed with the dominant foliation. An inverted metamorphic gradient is locally defined by sillimanite-garnet schists (625 degrees C) structurally above staurolite-garnet schists (550 degrees C) and implies ductile thrusting during the main phase of deformation. The exhumation that led to the recorded decompression was likely in response to crustal thickening due to ductile thrusting and subsequent denudation.

Rats' Learned Preferences for Flavors Encountered Early or Late in a Meal Paired with the Postingestive Effects of Glucose

Rats learn to prefer flavors that are followed by postingestive effects of nutrients. This experiment investigated whether the timing of a flavor (specifically, in the first or second half of the meal) influences learning about that flavor. Stronger learning about earlier or later flavorswould indicate when the rewarding postingestive effects of nutrients are sensed. Ratswith intragastric (IG) catheters drank saccharin-sweetened, calorically-dilute solutions with distinct flavors added, accompanied by IG infusion of glucose (+sessions) or water (−sessions). In both types of sessions, an “Early” flavorwas provided for the first 8 min and a “Late” flavor for the last 8 min. Thus, rats were trained with Early(+) and Late(+) in high-caloriemeals, and Early(−) and Late(−) in low-calorie meals. Strength of the learned preference for Early(+) and Late(+) was then assessed in a series of two-bottle choice tests between Early(+) vs. Early(−), Late(+) vs. Late(−), Early(+) vs. Late(+), and Early(−) vs. Late(−). Rats preferred both Early(+) and Late(+) over the respective (−) flavors. But Early(+)was only preferredwhen rats were tested hungry. Late(+) was preferred when rats were tested hungry or recently satiated. This indicates qualitatively different associations learned about flavors at different points in themeal.While not supporting the idea that postingestive effects become most strongly associated with later-occurring (“dessert”) flavors, it does suggest a reason dessert flavors may remain attractive in the absence of hunger.

Cultural Dynamics and Ceramic Resource Use at Late Bronze Age/Early Iron Age Troy, Northwestern Turkey

Changes in resource use over time can provide insight into technological choice and the extent of long-term stability in cultural practices. In this paper we re-evaluate the evidence for a marked demographic shift at the inception of the Early Iron Age at Troy by applying a robust macroscale analysis of changing ceramic resource use over the Late Bronze and Iron Age. We use a combination of new and legacy analytical datasets (NAA and XRF), from excavated ceramics, to evaluate the potential compositional range of local resources (based on comparisons with sediments from within a 10 km site radius). Results show a clear distinction between sediment-defined local and non-local ceramic compositional groups. Two discrete local ceramic resources have been previously identified and we confirm a third local resource for a major class of EIA handmade wares and cooking pots. This third source appears to derive from a residual resource on the Troy peninsula (rather than adjacent alluvial valleys). The presence of a group of large and heavy pithoi among the non-local groups raises questions about their regional or maritime origin. (C) 2012 Elsevier Ltd. All rights reserved.

The Resilience of Self-Esteem in Late Adulthood

OBJECTIVE: The authors examined the resilience of self-esteem after loss in the lives of older adults. Specifically, the authors investigated the relationship between loss and change in self-esteem during a 3-year period. METHOD: A subsample of older adults (n = 1,278) from the Americans' Changing Lives Study was used to examine loss in the domains of health, financial security, or work and career and self-esteem before and after the loss. RESULTS: There was a small but significant decrease in self-esteem between Wave I and Wave II of the study. Loss in one of the domains explained less than 1% of the variance in self-esteem change. DISCUSSION: The low incidence of loss and small change in high levels of self-esteem are further evidence of resilience in older adults' psychological well-being. The implications for older adults' use of cognitive strategies to manage losses and promote gains are discussed.

Paleoenvironment and Paleoecology of a Late Paleocene High-Latitude Terrestrial Succession, Arkose Ridge Formation at Box Canyon, Southern Talkeetna Mountains, Alaska

Paleogene sedimentary rocks of the Arkose Ridge Formation (Talkeetna Mountains, Alaska) preserve a record of a fluvial-lacustrine depositional environment and its forested ecosystem in an active basin among the convergent margin tectonic processes that shaped southern Alaska. An -800 m measured succession at Box Canyon indicates braid-plain deposition with predominantly gravelly deposits low in the exposure to sandy and muddy facies associations below an overlying lava flow sequence. U-Pb geochronology on zircons from a tuff and a sandstone within the measured section, as well as an Ar/Ar date from the overlying lava constrain the age of the sedimentary succession to between similar to 59 Ma and 48 Ma Fossil plant remains occur throughout the Arkose Ridge Formation as poorly-preserved coalified woody debris and fragmentary leaf impressions. At Box Canyon, however, a thin la-custrine depositional lens of rhythmically laminated mudrocks yielded fish fossils and a well-preserved floral assemblage including foliage and reproductive organs representing conifers, sphenopsids, monocots, and dicots. Leaf physiognomic methods to estimate paleoclimate were applied to the dicot leaf collection and indicate warm temperate paleotemperatures (-11-15 +/- -4 degrees C MAT) and elevated paleoprecipitation (-120 cm/yr MAP) estimates as compared to modem conditions; results that are parallel with previously published estimates from the partly coeval Chickaloon Formation deposited in more distal depositional environments in the same basin. The low abundance of leaf herbivory in the Box Canyon dicot assemblage (-9% of leaves damaged) is also similar to the results from assemblages in the meander-plain depositional systems of the Chickaloon. This new suite of data informs models of the tectonostratigraphic evolution of southern Alaska and the developing understanding of terrestrial paleoecology and paleoclimate at high latitudes during the Late Paleocene-Early Eocene greenhouse climate phase. (c) 2014 Elsevier B.V. All rights reserved.

Ceramics, Trade, Provenience and Geology: Cyprus in the Late Bronze Age

The island of Cyprus was a major producer of copper and stood at the heart of east Mediterranean trade networks during the Late Bronze Age. It may also have been the source of the Red Lustrous Wheelmade Ware that has been found in mortuary contexts in Egypt and the Levant, and in Hittite temple assemblages in Anatolia. Neutron Activation Analysis (NAA) has enabled the source area of this special ceramic to be located in a geologically highly localised and geochemically distinctive area of western Cyprus. This discovery offers a new perspective on the spatial organisation of Cypriot economies in the production and exchange of elite goods around the eastern Mediterranean at this time.