bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chapter 21 The Tambien Group, Northern Ethiopia (Tigre)
Authors: Miller Nathan R. , Avigad Dov , Stern Robert J. , Beyth Michael 
Published: December 2011

Abstract

The Tambien Group of northern Ethiopia (Tigre), with probable correlatives in Eritrea, is a 2–3-km-thick siliciclastic–carbonate succession that was deposited in an intra-oceanic arc platform setting within the southern Arabian–Nubian Shield (ANS) area (southern extension of the Nakfa Terrane) of the Mozambique Ocean. Its deposition occurred prior to ocean closure between converging fragments of East and West Gondwana and concomitant structural emergence of the East African Orogen (EAO). The Tambien Group is well exposed and best studied in the Mai Kenetal and Negash synclinoria, where litho- and chemostratigraphy (including δ
13
C
carb
,
87
Sr/
86
Sr) provide the basis for a composite reference section. Two glaciogenic intervals have been suggested from exposures within the Didikama and Matheos Formation in the Negash Synclinorium. No reliable palaeomagnetic data exist to constrain the palaeolatitude of Tambien Group deposition and the southern ANS, but palaeogeographic reconstructions and evaporite pseudomorphs in lower carbonate units (Didikama Formation) imply low to intermediate latitudes (<45°). Integration of available geochronological information (regional magmatism and detrital zircon) suggests
c.
775–660 Ma as a plausible window constraining deposition of the prospective glacial intervals.

The Tambien Group appears to preserve a coherent chemostratigraphic framework that can be effectively subdivided according to shifts in δ
13
C
carb
polarity [polarity intervals A (+), B (–), C (+), D (–)]. Slates underlying and interstratified with polarity interval A carbonate preserve evidence of extreme chemical weathering that lessened prior to deposition of polarity interval B carbonate. Tambien Group carbonate units have sedimentological characteristics consistent with both shallow and deeper marine depositional settings. The lower prospective glacial interval lacks diagnostic sedimentological evidence of synglacial deposition, but is overlain by negative δ
13
C carbonate (polarity interval B) with sedimentological characteristics consistent with well-documented cap-carbonate successions. The upper prospective glacial interval in the Negash Synclinorium (Matheos Diamictite) best exhibits characteristics consistent with glaciogenic deposition (matrix-supported polymictic clasts, possible dropstones, possible bullet-nosed and striated clasts). In contrast to pericratonic rift margin settings that are common for Cryogenian glaciogenic deposits, palaeogeographic reconstructions for the 775–660 Ma timeframe place northern Ethiopia within an intra-oceanic setting that was likely far removed from cratonic hinterlands. More work on Tambien Group sedimentology, geochronology and palaeogeography is required to better evaluate the extent and timing of glacial conditions associated with the prospective glaciogenic intervals.

Supplementary material:

Supplementary Table 21.1 of Tambien Group geochronological age constraints is available at
http://www.geolsoc.org.uk/SUP18462
.
Chapter 29 The Tsagaan Oloom Formation, southwestern Mongolia
Authors: Macdonald Francis A. 
Published: December 2011

Abstract
The Tsagaan Oloom Formation (Fm.) in southwestern Mongolia contains two Neoproterozoic glacial deposits, with diamictite in the Maikhan Ul Member (Mb.) and in the Khongoryn Mb., which are separated by over 500 m of limestone. The Maikhan Ul Mb. ranges in thickness between 5 m and greater than 300 m, expanding in deeper-water sections towards the SW, where it is composed of two massive diamictites separated by over 100 m of sandstone, siltstone and shale. The basal 10 m of the overlying Tayshir Mb. of the Tsagaan Oloom Fm. consists of a fine-laminated, dark grey limestone. The Khongoryn Mb. is composed primarily of limestone clasts in a shale matrix, and is between 0 and 23 m thick. The overlying Ol Mb. contains sedimentary structures characteristic of basal Ediacaran cap carbonates including micropeloids, tubestone stromatolites, giant wave ripples and former aragonite crystal fans. U–Pb evaporation ages from zircons in the underlying Dzabkhan Volcanics constrain the Tsagaan Oloom Fm. to <773 Ma, and tuffs within the Maikhan Ul and Tayshir members testify to the potential for additional geochronology. The Cryogenian organic-rich limestone of the Tayshir Mb., which lies between the two glacial deposits, is ideally suited for geochemical studies and has been the subject of several carbon, strontium and rare earth element investigations. Limited palaeomagnetic studies suggest a mid- to low-latitude position of the Dzabkhan platform during deposition of the glaciogenic strata, and additional studies are in progress.
Chapter 31 The Blaini Formation of the Lesser Himalaya, NW India
Authors: Etienne James L. , Allen Philip A. , Guerroué Erwan le , Heaman Larry , Ghosh Sumit K. , Islam Rafique 
Published: December 2011

Abstract

Neoproterozoic glaciogenic deposits crop out widely across the Lesser Himalaya fold and thrust belt in NW India. Underlain by the siliciclastic Simla and Jaunsar Groups, the Blaini Formation (Fm.) includes at least two thick and regionally extensive diamictite units, separated by siliciclastics and argillites and capped by a pink microcrystalline dolomite. A glaciogenic origin is supported by the presence of relatively abundant striated clasts and the local preservation of polished and striated pavement on underlying Simla Group clastics. The cap dolostone is isotopically light with respect to both
13
C and
18
O, which show strong covariance. The Blaini is ubiquitously deformed, incorporated in regional-scale folds and thrusts, and exhibits locally intensive intra-formational deformation. Until recently, geochronological constraints have remained poor, but new detrital zircon ages from diamictite samples provide a maximum age limit of 692±18 Ma (
207
Pb/
206
Pb). Reliable palaeomagnetic data are required to constrain the position of this important passive continental margin in palaeogeographical reconstructions.
Chapter 33 Neoproterozoic glaciogenic diamictites of the Tarim Block, NW China
Authors: Zhu Maoyan , Wang Haifeng 
Published: December 2011

Abstract

Neoproterozoic glaciogenic outcrops are mostly limited to the southwestern and northwestern margins of the Tarim basin and the Tianshan Mountains. Only two glaciogenic diamictites are recorded in the Neoproterozoic successions from the Tielikeli and Aksu-Wusi areas of the Tarim basin. The lower diamictite from the Polong Formation in the Tielikeli area is
c.
800 m thick. The upper diamictite in the area is very thin (Yutang diamictite, 10 m; Yulmeinak diamictite, 51 m). In contrast to the Tarim basin, the Neoproterozoic successions along the northern margin of the Tarim Block in the Tianshan Mountains record three or four glaciogenic diamictites, which are well developed and crop out in the Qurugtagh area. Although the glaciogenic nature of the oldest Beiyixi diamictite remains questionable, all other diamictites (Altungol, Tereeken and Hankalchough) exhibit distinct glaciogenic sedimentary features. SHRIMP zircon U–Pb dating demonstrate that the Bayisi diamictite was deposited between 740±7 Ma and 725±10 Ma, the Altungol and Tereeken diamictites between 725±10 Ma and 615±6 Ma, respectively, and the Hankalchough diamictite between 615±6 Ma and
c.
542 Ma. Carbonates atop the Altungol, Tereeken and Hankalchough diamictites show distinct C-isotopic values that are typical for those recorded in ‘cap carbonates’ on other continents. The striking similarity between the cap carbonate of the Tereeken and Marinoan-age Nantuo diamictites further support a 635 Ma ‘Marinoan’ age for the Tereeken glaciation. Unlike the 582 Ma Gaskiers glaciations of Newfoundland, the Hankalchough diamictite is possibly <551 Ma, as suggested by C-isotope chemostratigraphy and biostratigraphy, indicating that post-Marinoan glaciations on different continents may be diachronous.

Supplementary material:

Data are available at:
http://www.geolsoc.org.uk/SUP18469
.
Chapter 4 Chemostratigraphy and the Neoproterozoic glaciations
Authors: Halverson Galen P. , Shields-Zhou Graham 
Published: December 2011

Abstract

Although the pre-glacial Proterozoic isotopic record is poorly constrained, it is apparent that the chemical and isotopic composition of the oceans began to change during the early to mid-Neoproterozoic and experienced considerable fluctuations alongside climatic instability during much of the subsequent Cryogenian and Ediacaran periods. The earliest known large negative δ
13
C excursion appears to post-date 811 Ma and fluctuations became progressively more extreme, culminating in the late-Ediacaran ‘Shuram–Wonoka’ anomaly. The negative excursions are commonly associated with pre-glacial and post-glacial times, while extremely high δ
13
C values are characteristic of strata between glaciations. The precise causal mechanism for these excursions is subject to debate. Seawater
87
Sr/
86
Sr rose during the Neoproterozoic, with abrupt increases following deglaciation consistent with enhanced weathering rates. Reported marine sulphate and pyrite δ
34
S data exhibit marked variation through this interval, although the changes are not always consistent within or between sedimentary successions of equivalent age. Iron-speciation studies indicate that much of this variation was caused by fluctuating and low sulphate concentrations in seawater, which at times led to the build-up of ferruginous conditions in the ocean. The application of chemostratigraphy to understanding and correlating the Neoproterozoic glaciations evokes considerable controversy, and many questions persist regarding the reliability and calibration of the δ
13
C,
87
Sr/
86
Sr and δ
34
S record. Nevertheless, the individual glaciations appear to be characterized by distinct combined chemostratigraphic signatures, in large part due to the generally increasing strontium isotope composition of seawater through the Neoproterozoic Era.
Chapter 40 The Kingston Peak Formation in the eastern Death Valley region
Authors: Mrofka David , Kennedy Martin 
Published: December 2011

Abstract
The late Neoproterozoic Kingston Peak Formation (Fm.) is a several-kilometre-thick sedimentary succession primarily influenced by syndepositional tectonism and located in the region around Death Valley, California (Fig. 40.1). Its distribution is divisible into an eastern facies assemblage, the subject of this paper, and a western facies assemblage covered in a separate chapter. The diamictite-bearing Kingston Peak Fm. is bounded by the underlying shallow platform carbonates of the Beck Spring Fm. and overlain by the Noonday Dolomite. There is an absence of direct palaeolatitude or radiometric age constraints and any correlation is based on broad similarities with other coarse-grained strata (diamictite) located in a northward trending belt along the Cordilleran miogeocline. The overlying Noonday Dolomite has been interpreted to be a late Cryogenian ‘cap carbonate’ and shares a set of unique facies associations and isotopic and lithological characteristics with other late Neoproterozoic post-glacial carbonate intervals in Namibia, Canada, Australia and Brazil. Research to date has focused on understanding local basin evolution, glacial sedimentology, correlation between the eastern and western facies assemblages and initiation and development of the North American Cordillera. The intimate association of tectonic and glacial facies with rapid local thickness and facies changes corresponding with syn-sedimentary faulting is the most distinctive stratigraphic characteristic of the Kingston Peak Fm. The complex local stratigraphy complicates correlation both within the Death Valley region as well as globally, and pending absolute age dates, does not fit easily with conventional Cryogenian Period glacial models identifying two or more discrete ice ages.
Chapter 47 The Bebedouro Formation, Una Group, Bahia (Brazil)
Authors: Guimarães J. T. , Misi A. , Pedreira A. J. , Dominguez J. M. L. 
Published: December 2011

Abstract
The Bebedouro Formation (Fm.) is a Neoproterozoic glaciogenic succession at the base of the Una Group on the São Francisco Craton. The glaciogenic sequence is composed of diamictites, pelites and sandstones with a variety of lithofacies that are grouped into four associations: (i) ice-contact, (ii) pro-glacial, (iii) ice-rafted and (iv) aeolian (extraglacial). Thus, the Bebedouro Fm. is interpreted to have been deposited in a shelf marine environment where glacio-proximal sedimentation dominated. It variably overlies Palaeoproterozoic/Archaean basement and Mesoproterozoic metasedimentary rocks of the Chapada Diamantina Group.

The overlying carbonate succession (Salitre Fm.) is informally subdivided into five mappable units. Unit C, at the base, is composed of red argillaceous dolostone with typical negative δ
13
C signatures averaging –5.1‰ (VPDB). Unit B consists of grey laminated limestones that grade upward into grey dolostone with tepee structures of Unit B1; both have δ
13
C values around 0‰. The overlying Unit A consists of interbeds of greyish marl, shales and siltstones grading upward into massive black organic-rich limestone with oolitic and pisolitic beds of Unit A1. Positive δ
13
C signatures averaging +8.5‰ VPDB characterize the black limestones of Unit A1.
87
Sr/
86
Sr ratios of well-preserved samples of these carbonate units show values of 0.70745 and 0.70765. These units can be correlated litho- and chemostratigraphically with formations of the Bambuí Group (São Francisco Basin) to the west.
Chapter 48 Neoproterozoic successions of the São Francisco Craton, Brazil: the Bambuí, Una, Vazante and Vaza Barris/Miaba groups and their glaciogenic deposits
Authors: Misi Aroldo , Kaufman Alan J. , Azmy Karem , Dardenne Marcel Auguste , Sial Alcides Nóbrega , de Oliveira Tolentino Flávio 
Published: December 2011

Abstract

The Neoproterozoic successions of the São Francisco Craton are primarily represented by the Bambuí and Una groups, deposited in cratonic epicontinental basins, and by the Vazante and Vaza Barris/Miaba groups, which accumulated on passive margins on the edges of the craton. The epicontinental basins comprise three megasequences: glaciogenic, carbonate platform (marine) and dominantly continental siliciclastics. Possible correlative sequences are observed in the passive margin deposits. At least two major transgressive–regressive sea-level cycles occurred during the evolution of the carbonate megasequence, which lies above glaciomarine diamictites of probable early Cryogenian (i.e. Sturtian) age. C, O, Sr and S isotope trends from analyses of well-preserved samples, together with lithostratigraphic observations, provide reasonable correlations for most of the Neoproterozoic successions of the São Francisco Craton. The
87
Sr/
86
Sr record of these successions, ranging from 0.70769 to 0.70780, supports the proposed correlation with the Bambuí, Una and Vaza/Barris successions, and with the basal units of the Vazante Group. In addition, C-isotope positive excursions ranging from +8.7 to +14‰ and negative excursions from –5.7 to –7‰ VPDB in the Bambuí, Una and Vaza-Barris successions provide key markers for correlations. The precise ages of the sedimentation in these successions remains a matter of debate, but organic shales of two units of the Vazante Group have been dated by Re–Os techniques in two different laboratories, both yielding Mesoproterozoic ages. The Neoproterozoic and Mesoproterozoic successions preserve significant glaciogenic deposits.
Chapter 54 The controversial stratigraphy of the glacial deposits in the Tandilia System, Argentina
Authors: Pazos P. J. , Rapalini A. 
Published: December 2011

Abstract

In the Ediacaran–Cambrian Tandilia System of central Argentina, the glacial origin of the thin (10 m) Sierra del Volcán Formation (Fm.) has been recognized for many years (
Spalletti & del Valle 1984
), being the first undisputed glacial deposits recorded in the Río de la Plata craton. It consists of three units: (i) a basal polymictic diamictite with a kaolin-rich matrix, (ii) a middle pelite with heterolithic levels, undulatory stratification, symmetric ripples, and outsized clasts previously interpreted as dropstones, and (iii) an upper polymictic diamictite with subtle normal grading. Here, this poorly age-constrained formation is reviewed from a stratigraphic and regional context and compared with other putative glaciogenic intervals at the base of the Cerro Largo Fm. and in the Punta Mogotes borehole.
Chapter 66 Mid-Ediacaran ice-rafting in the Adelaide Geosyncline and Officer Basin, South Australia
Authors: Gostin Victor A. , McKirdy David M. , Webster Lynn J. , Williams George E. 
Published: December 2011

Abstract

Sedimentary features characteristic of ice-rafting are present in the Bunyeroo Formation (Wilpena Group) of the Adelaide Geosyncline and in the coeval Dey Dey Mudstone (Ungoolya Group) of the eastern Officer Basin (Figs 66.1 & 66.2), providing evidence of a mid-Ediacaran glacial climate in South Australia. The Acraman asteroid impact, a negative shift in marine δ
13
C, and a major acritarch turnover coincided with this frigid epoch.
Retinoid-Regulated FGF8f Secretion by Osteoblasts Bypasses Retinoid Stimuli to Mediate Granulocytic Differentiation of Myeloid Leukemia Cells
Authors: Chaudhry Parvesh , Yang Xiaochun , Wagner Michael , Jong Ambrose , Wu Lingtao 
Published: December 2011

Abstract
Signaling from the human hematopoietic stem cell (HSC) niche formed by osteoblastic cells regulates hematopoiesis. We previously found that retinoic acid receptor alpha (RARα), a transcription factor activated by retinoic acid (RA), mediates both granulocytic and osteoblastic differentiation. This effect depends on decreased phosphorylation of serine 77 of RARα (RARαS77) by the cyclin-dependent kinase-activating kinase (CAK) complex, a key cell-cycle regulator. In this article, we report that, by suppressing CAK phosphorylation of RARα, RA induces FGF8f to mediate osteosarcoma U2OS cell differentiation in an autocrine manner. By contrast, paracrine FGF8f secreted into osteoblast-conditioned medium by U2OS cells transduced with FGF8f or a phosphorylation-defective RARαS77 mutant, RARαS77A, bypasses RA stimuli to cross-mediate granulocytic differentiation of different types of human leukemic myeloblasts and normal primitive hematopoietic CD34+ cells, possibly through modulating mitogen-activated protein kinase (MAPK) pathways. Further experiments using recombinant human FGF8f (rFGF8f) stimuli, antibody neutralization, and peptide blocking showed that paracrine FGF8f is required for mediating terminal leukemic myeloblast differentiation. These studies indicate a novel regulatory mechanism of granulocytic differentiation instigated by RA from the HSC niche, which links loss of CAK phosphorylation of RARα with paracrine FGF8f-mediated MAPK signaling to mediate leukemic myeloblast differentiation in the absence of RA. Therefore, these findings provide a compelling molecular rationale for further investigation of paracrine FGF8f regulation, with the intent of devising HSC niche-based FGF8f therapeutics for myeloid leukemia, with or without RA-resistance. Mol Cancer Ther; 11(2); 267–76. ©2011 AACR.
Long-term antipsychotic polypharmacy: how does it start, why does it continue?
Authors: Grech Patrice , Taylor David 
Published: December 2011

Background: Antipsychotic polypharmacy remains a widespread and persistent practice, despite a lack of empirical evidence to support its safety and efficacy. This study aimed to assess antipsychotic treatment prior to the initiation of polypharmacy and ascertained clinicians’ reasons for coprescribing long term. We also aimed to determine patterns of antipsychotic coprescription and associated outcome. Method: Prescription charts across a large mental health trust were reviewed to identify all patients coprescribed two or more antipsychotics excluding clozapine. For those receiving antipsychotic polypharmacy for at least 6 months, electronic patient records were examined to obtain demographic data, documented reasons for initiating polypharmacy and prior prescribing information. Sequence of prescribing, clinical outcome, adverse effects and prescriber considerations to revert to monotherapy were determined. Results: In all, 38 patients had been receiving two antipsychotics excluding clozapine for longer than 6 months. In 39% of cases patients had been prescribed no or only one antipsychotic before initiation of polypharmacy while 48% had been trialled on clozapine. The most frequently documented reason for coprescribing was that residual psychotic symptoms remained with monotherapy. An improvement in psychotic symptoms was documented in 26% of patients receiving polypharmacy. Prescribers considered stopping polypharmacy in 23 patients. Conclusion: Antipsychotics were coprescribed largely to improve symptoms and clinical outcome in patients with inadequate response to monotherapy. Polypharmacy was not solely reserved for patients in whom all other therapeutic options had failed. There was some evidence to suggest that patients did benefit from coprescription, albeit at the expense of an increased adverse effect burden. Prospective randomized trials of specific antipsychotic combinations are required to assess the therapeutic utility of this under-researched practice.
Rehabilitation, weaning and physical therapy strategies in chronic critically ill patients
Authors: Ambrosino N. , Venturelli E. , Vagheggini G. , Clini E. 
Published: December 2011

In critically ill patients, a prolonged hospital stay, due to the initial acute insult and adverse side-effects of drug therapy, may cause severe late complications, such as muscle weakness, prolonged symptoms, mood alterations and poor health-related quality of life.The clinical aims of physical rehabilitation in both medical and surgical intensive care units (ICUs) are focussed on the patient to improve their short- and even long-term care.The purpose of this article is to review the currently available evidence on comprehensive rehabilitation programmes in critically ill patients, and describe the key components and techniques used, particularly in specialised ICUs.Despite the literature suggesting that several techniques have led to beneficial effects and that muscle training is associated with weaning success, scientific evidence is limited. Due to limitations in undertaking comparative studies in ICUs, further studies with solid clinical short- and long-term outcome measures are now welcomed.