Geological Community Research Articles

NASA’S PLANETARY GEOLOGIC MAPPING PROGRAM: OVERVIEW

NASA’s Planetary Science Division supports the geologic mapping of planetary surfaces through a distinct organizational structure and a series of research and analysis (R&A) funding programs. Cartography and geologic mapping issues for NASA’s planetary science programs are overseen by the Mapping and Planetary Spatial Infrastructure Team (MAPSIT), which is an assessment group for cartography similar to the Mars Exploration Program Assessment Group (MEPAG) for Mars exploration. MAPSIT’s Steering Committee includes specialists in geological mapping, who make up the Geologic Mapping Subcommittee (GEMS). I am the GEMS Chair, and with a group of 3-4 community mappers we advise the U.S. Geological Survey Planetary Geologic Mapping Coordinator (Dr. James Skinner) and develop policy and procedures to aid the planetary geologic mapping community. GEMS meets twice a year, at the Annual Lunar and Planetary Science Conference in March, and at the Annual Planetary Mappers’ Meeting in June (attendance is required by all NASA-funded geologic mappers). Funding programs under NASA’s current R&A structure to propose geological mapping projects include Mars Data Analysis (Mars), Lunar Data Analysis (Moon), Discovery Data Analysis (Mercury, Vesta, Ceres), Cassini Data Analysis (Saturn moons), Solar System Workings (Venus or Jupiter moons), and the Planetary Data Archiving, Restoration, and Tools (PDART) program. Current NASA policy requires all funded geologic mapping projects to be done digitally using Geographic Information Systems (GIS) software. In this presentation we will discuss details on how geologic mapping is done consistent with current NASA policy and USGS guidelines.

Symmetrized Bingham distribution for representing texture: parameter estimation with respect to crystal and sample symmetries

The quaternion Bingham distribution has been used to model preferred crystallographic orientation, or crystallographic texture, in polycrystalline materials in the materials science and geological communities. A primary difficulty in applying the Bingham distribution has been the lack of an efficient method for fitting the distribution parameters with respect to the material's underlying crystallographic symmetry or any statistical sample symmetry due to processing. This paper presents a symmetrized distribution, based on the quaternion Bingham, which can account for any general combination of crystallographic or sample symmetries. A numerical scheme is also introduced for estimating the parameters of the symmetrized distribution based on the well known expectation maximization algorithm.

Earthquake Induced Sedimentary Structures (Seismites): Geoconservation and Promotion as Geological Heritage (Lake Van-Turkey)

The Lake Van Basin, located at the collision zone of the Eurasian and Arabian plates, has great potential in terms of geological heritage. The world’s largest soda lake which gives its name to the basin contains magnificent geological structures. Lacustrine deposits of the lake represent important clues about seismic activity during the Late Quaternary in addition to its sedimentological and paleontological background. Seismites—deformational structures which are formed during earthquakes in unconsolidated sediments—are very rare geologic phenomena. These structures, formed by earthquakes of magnitude ≥5 under suitable conditions, provide valuable information about the responsible faults and their seismic repetition frequency for the region. Today, rising awareness of geological heritage is a glimmer of hope for the protection and preservation of these rare structures in the Lake Van Basin for the generations to come. Conservation of these structures will also help the protection of other naturally, historically, and culturally significant geological beauties. The responsibility for the promotion and conservation of these geological heritages should be a mission not only for the hosting country but also for the entire geological community.

Social Learning Theories—An Important Design Consideration for Geoscience Fieldwork

ABSTRACTThe nature of field trips in geoscience lends them to the application of social learning theories for three key reasons. First, they provide opportunity for meaningful practical experience and promote effective learning afforded by no other educational vehicle in the subject. Second, they are integral for students creating a strong but changing sense of identity from student, to geoscience student, to practicing professional geoscientist. Third, they help students to develop and build their own communities of practice within the field trips akin to the professional communities of practice they may be expected to contribute to, and pursue inbound trajectories into, in the future. Furthermore field trips encourage students to actively engage and initiate trajectories within the wider disciplinary geological community of practice. The building and effectiveness of communities of practice are important because the nature of geoscience as an integrative subject lends itself to relying on such communities. Therefore, the designers of field-trip programs should be aware of this social learning theory and ensure that working within communities of practice is integral to the activities they design. In so doing, we will produce graduates in the subject that will serve the requirements of industry and academia alike, in addition to other graduate careers. Students that most successfully participate in field trips are characterized by independence in their learning and increasing self-efficacy.

The Ordovician Exposed: Contributions from the 12th International Symposium on the Ordovician System

For nearly two centuries some of the world's most notable geologists and paleontologists have intensively studied the Ordovician rocks of North America. The "layer cake" sedimentary strata deposited in the vast epicontinental seas of the interior and the flanking folded and thrusted mountain belts provided both complex problems and fertile ground for new theories and methods. The problem of correlating between regions in the large cratonic interior and between disparate biofacies gave rise to exciting new studies in sequence, event, quantitative, and chemostratigraphy. Distinctive and traceable marker beds, geochemically fingerprinted K-bentonites, and carbon isotope excursions allow for correlation with unprecedented precision, which leads to new questions (and answers) about Ordovician climate and oceanography, global carbon cycling, and the timing of tectonic events. Recent innovations in using geochemistry to study the ancient environment has greatly increased our understanding of Ordovician climate cyclicity and its effects on Earth's biota. Advances in geochronology have given the geologic community amazingly precise dates on Ordovician K-bentonites, increasing the precision and usefulness of our most fundamental tool the geologic time scale. In short, it is an exciting time in Ordovician research and the highlights of this work were presented at the 12th International Symposium on the Ordovician System. The conference included fifty-nine talks and 18 posters presentations given by over 80 delegates representing 14 different countries. Its overall theme was Integrated Stratigraphy, and as noted above comprises the latest research in sedimentary geochemistry, geochronology, sequence stratigraphy, event stratigraphy, and quantitative stratigraphic methods. These studies provide the stratigraphic framework and paleoenvironmental context for examining the evolution, diversification, and extinction of Ordovician life. ISOS 2015 also offered 4 field trips - 3 to the southern, central, and northern Appalachian Mountains, and one to eastern and central Oklahoma - to examine classic exposures of Ordovician rocks and the only Ordovician GSSP in the United States. This theme issue includes nine contributed papers that are an expansion on the presentations of 12th International Symposium on the Ordovician System. We would like to thank the presenters, field trip leaders, and manuscript reviewers, all of whom are essential to a successful symposium.

Obituary: Roger Frank Vaughan (1948-2015)

It is with deep sadness I have to report that Roger Vaughan has peacefully passed away at Gloucester Royal Hospital aged 66. He was until his retirement in August 2013, the Curator of Geology at Bristol Museum & Art Gallery. Roger had a lifelong love of geology and was well respected within the geological community, especially in the west of England where he spent most of his geological career. He considered himself one of the lucky people who managed to turn his hobby into a job.

Rethinking post-Hercynian basin development: Eastern Mediterranean Region

ABSTRACT The geological community has broadly accepted that the region of NE Africa and NW Arabia deformed under tension during the post-Hercynian disintegration of northern Gondwana. Further, it has also generally accepted that sedimentation occurred within extensional half-grabens that formed along the length of what was then the southern margin of the Neo-Tethys Ocean. Consensus is that Alpine age compression then forced inversion of these half-grabens to form the well-known Syrian Arc structures that stretch from the Western Desert of Egypt to NE Syria. As new data has become available (Enclosures I and II), there are indications that an alternative mechanism, founded in continuous compression rather than extension then compression, better explains the tectonics and sedimentary history of the region since the late Palaeozoic. Data from Syria, Jordan, the Levant and Egypt demonstrate that distinct post-Hercynian Orogeny, Tethyan and Alpine sequences (basins) lie on a final, deeply eroded and folded Hercynian Unconformity, and that this surface refolded post-Hercynian time to form the confining walls of a single trough extending from NE Syria to the Western Desert of Egypt. Prior to the deposition of the first Tethyan basin in the late Carboniferous, the Hercynian Unconformity surface deformed to establish a plate-scale arch, the Levant Arch, that extended from NE Syria and southern Turkey, over 1,500 km southwest to the three corners region of Egypt, Sudan and Libya. This arch refolded in the late Palaeozoic to form the early Levant Trough composed of the Palmyride Trough, its extension under the Eastern Mediterranean and the Levant, through the Sinai and into western Egypt. Contrary to the now established idea that the southern margin of the Carboniferous–Permian Tethyan Ocean was a “passive margin”, the trough and internally constrained basins, slowly narrowed and deepened under continuous compression from the southeast from at least the late Palaeozoic to the Present. Each internal, distinct basin sequence is well defined by long periods of slow, low-energy, laterally persistent, sedimentation, separated from underlying and overlying basin sequences by almost equally long periods of erosion or non-deposition, coincident with increased regional structuring and volcanism. Each new basin, following a cessation of this regional structural activity, found itself nested within its predecessor, with the older basin lying slightly counter-clockwise to the younger. It is proposed that counter-clockwise, regional (and basin) rotation was facilitated by newly documented NW-oriented cross-shears, with inter-basin periods of erosion or non-deposition due to whole-basin (regional) uplift, forced by trough narrowing. Tectonic-scale geologic features, such as cross-basin and regional shears, trough margin uplift and northwest migration, laterally extensive, sheet-like sedimentation, sediment feathering onto unfaulted margins, regional erosion related to whole-basin uplift and massive flank gravity sliding with resultant down-slope buckle folding, taken together, attest to compression as the driving agent. Whole-basin and regional, counter-clockwise rotation through time, suggests a constant direction of compression. Understanding the correlation of sedimentary fill to local and regional structural events brings new insight to the deformation of the northern regions of Gondwana during the closure of Tethyan oceans. This model may also apply on a larger scale of whole-plate deformation.

The Ordovician Exposed: Short Papers, Abstracts, and Field Guides for the 12th International Symposium on the Ordovician System

For nearly two centuries some of the world’s most notable geologists and paleontologists have intensively studied the Ordovician rocks of North America. The “layer cake” sedimentary strata deposited in the vast epicontinental seas of the interior and the flanking folded and thrusted mountain belts provided both complex problems and fertile ground for new theories and methods. The problem of correlating between regions in the large cratonic interior and between disparate biofacies gave rise to exciting new studies in sequence, event, quantitative, and chemo-stratigraphy. Distinctive and traceable marker beds, geochemically fingerprinted K-bentonites, and carbon isotope excursions allow for correlation with unprecedented precision, which led to new questions (and answers) about Ordovician climate and oceanography, global carbon cycling, and the timing of tectonic events. Recent innovations in using geochemistry to study the ancient environment has greatly increased our understanding of Ordovician climate cyclicity and its effects on Earth’s biota. Advances in geochronology have given the geologic community amazingly precise dates on Ordovician K-bentonites, increasing the precision and usefulness of our most fundamental tool – the geologic time scale. It is an exciting time in Ordovician research and the highlights of this work are presented here at the 12th International Symposium on the Ordovician System. The conference includes fifty-nine talks and 18 posters presentations given by over 80 delegates representing 14 different countries. Its overall theme is Integrated Stratigraphy, and as noted above comprises the latest research in sedimentary geochemistry, geochronology, sequence stratigraphy, event stratigraphy, and quantitative stratigraphic methods. These studies provide the stratigraphic framework and paleoenvironmental context for examining the evolution, diversification, and extinction of Ordovician life. ISOS 2015 offers 4 field trips - 3 to the southern, central, and northern Appalachian Mountains, and one to eastern and central Oklahoma - to examine classic exposures of Ordovician rocks and the only Ordovician GSSP in the United States. Finally, we would like to thank the presenters, field trip leaders, and manuscript reviewers, all of whom are essential to a successful symposium. On behalf of the entire Organizing Committee, Stephen A. Leslie, Daniel Goldman, and Randall C. Ordorff

A Formação Serra Alta, Permiano, no centro-leste do Estado de São Paulo, Bacia do Paraná, Brasil

A individualização e o mapeamento da Formação Serra Alta no Estado de São Paulo sempre foi motivo de controvérsia na comunidade geológica. Apesar de apresentar extensão comparável à Formação Irati em subsuperfície, a unidade ainda carece de estudos mais acurados acerca de seu posicionamento estratigráfico, conteúdo fossilífero, sistema deposicional e idade. Na região centro-leste do Estado de São Paulo, a Formação Serra Alta sucede estratigraficamente a Formação Irati, sendo constituída por depósitos pelíticos cinza escuros. A unidade é mapeada desde o limite sul do estado até o Domo de Gibóia, no Município de Rio das Pedras. Neste local, as formações Serra Alta e Teresina são substituídas pelos depósitos pelíticos da Formação Corumbataí, que se estende para norte, além do limite do Estado de São Paulo, e pode ser considerada unidade correlata a estas. Neste estudo, são apresentadas seções colunares e caracterizados os contatos da Formação Serra Alta com as formações permianas verticalmente contíguas. É apresentada também detalhada análise de fácies, com a finalidade de caracterizar o sistema deposicional. A análise de perfis de sondagem possibilitou também melhor compreensão dos padrões arquiteturais da Formação Serra Alta, auxiliando na determinação de sua real distribuição e posição estratigráfica na porção centro-sul do estado. A integração das informações obtidas permitiu identificar tendências de empilhamento transgressivo particulares, contribuindo para o detalhamento da sucessão predominantemente regressiva em que se depositaram as unidades permianas da Bacia do Paraná.

SEPRAN: A versatile finite-element package for a wide variety of problems in geosciences

Numerical modelling of geological processes, such as mantle convection, flow in porous media, and geothermal heat transfer, has become quite common with the increase in computing and the availability of usable software. Today modelling these dynamical processes entails the solving of the governing equations involving the mass, momentum, energy and chemical transport. These equations represent partial differential equations and must be solved on powerful enough computers because they require sufficient spatial and temporal resolution to be useful. We describe here the salient and outstanding features of the SEPRAN software package, developed in the Netherlands, as a case study for a robust and user-friendly software, which the geological community can utilize in handling many thermal-mechanical-chemical problems found in geology, which will include geothermal situations, where many types of partial differential equations must be solved at the same time with thermodynamical input parameters.

Geospatial Resources for the Geology Community: The USGS National Map

Geospatial data are a key component of investigating, interpreting, and communicating the geological sciences. Locating geospatial data can be time-consuming, which detracts from time spent on a study because these data are not obviously placed in central locations or are served from many disparate databases. The National Map of the US Geological Survey is a publicly available resource for accessing the geospatial base map data needs of the geological community from a central location. The National Map data are available through a viewer and download platform providing access to eight primary data themes, plus the US Topo and scanned historical topographic maps. The eight themes are elevation, orthoimagery, hydrography, geographic names, boundaries, transportation, structures, and land cover, and they are being offered for download as predefined tiles in formats supported by leading geographic information system software. Data tiles are periodically refreshed to capture the most current content and are an efficient method for disseminating and receiving geospatial information. Elevation data, for example, are offered as a download from the National Map as 1° × 1° tiles for the 10- and 30- m products and as 15′ × 15′ tiles for the higher-resolution 3-m product. Vector data sets with smaller file sizes are offered at several tile sizes and formats. Partial tiles are not a download option—any prestaged data that intersect the requesting bounding box will be, in their entirety, part of the download order. While there are many options for accessing geospatial data via the Web, the National Map represents authoritative sources of data that are documented and can be referenced for citation and inclusion in scientific publications. Therefore, National Map products and services should be part of a geologist’s first stop for geospatial information and data.

A past-millennium maximum in postglacial activity from Volcán Chaitén, southern Chile

Volcan Chaiten (southern Chile, ∼43°S) initiated an historically unprecedented eruption in A.D. 2008, surprising the local inhabitants, Chilean and Argentine authorities, and the geologic community. Available data at the time indicated an absence of explosive eruptions from this rhyolitic volcano since a large-magnitude eruptive event dated at ca. 10,500 yr B.P. We present lake-sediment data from Lago Teo, a small closed-basin lake located in the immediate vicinity of both Chaiten township and the volcano, that spans the past ∼10,000 yr and contains 26 pyroclastic fallout deposits. Glass-shard electron microprobe analyses revealed ten rhyolitic tephras indistinguishable in composition from the 2008 Volcan Chaiten eruption, and ten others potentially derived from the Michinmahuida volcanic complex. Among the rhyolites, we detected three closely spaced tephras deposited between ca. 9460 and 9680 yr B.P., followed by two thick tephras dated at ca. 7700 and ca. 5080 yr B.P. Three other closely spaced tephras occur between ca. 600 and 850 yr B.P., the most recent prehistoric event at ca. 420 yr B.P., and a 3-cm-thick tephra deposited during the 2008 event. We calculate a median recurrence of ∼310 yr between eruptive events from all sources over the past ∼10,000 yr, and ∼200 yr between Volcan Chaiten events over the past millennium. Our results not only challenge the notion of an ∼10,500-yr-long quiescence for Volcan Chaiten activity, but also suggest that the 2008 eruption was an overdue phenomenon in the context of its postglacial eruptive history, illustrating the advantage and absolute necessity of utilizing lake-sediment archives for developing continuous well-dated time series inventories of explosive volcanic events.

Soil science and its interface with the history of geology community

Despite the historical origins of soil science as a geological science, scholarship in the history of soil science remains an outlier with respect to the presently structured history of geological sciences community. The history-oriented activities of the Soil Science Society of America, the European Geosciences Union, and the International Union of Soil Sciences show active efforts to document and extend knowledge of soil science history. An overview of pedology and its numerous links to geomorphology and other geological specialties is presented. Geologists were involved in early soil mapping, soil degradation studies, creation of soil classification systems, and development of the soil geomorphology subfield, each case demonstrating strong historical ties between geology and soil science. Areas of common interest between soil science and geology offer new opportunities for integration and cooperation in Earth science history going forward.

A community-based geological reconstruction of Antarctic Ice Sheet deglaciation since the Last Glacial Maximum

A robust understanding of Antarctic Ice Sheet deglacial history since the Last Glacial Maximum is important in order to constrain ice sheet and glacial-isostatic adjustment models, and to explore the forcing mechanisms responsible for ice sheet retreat. Such understanding can be derived from a broad range of geological and glaciological datasets and recent decades have seen an upsurge in such data gathering around the continent and Sub-Antarctic islands. Here, we report a new synthesis of those datasets, based on an accompanying series of reviews of the geological data, organised by sector. We present a series of timeslice maps for 20 ka, 15 ka, 10 ka and 5 ka, including grounding line position and ice sheet thickness changes, along with a clear assessment of levels of confidence. The reconstruction shows that the Antarctic Ice sheet did not everywhere reach the continental shelf edge at its maximum, that initial retreat was asynchronous, and that the spatial pattern of deglaciation was highly variable, particularly on the inner shelf. The deglacial reconstruction is consistent with a moderate overall excess ice volume and with a relatively small Antarctic contribution to meltwater pulse 1a. We discuss key areas of uncertainty both around the continent and by time interval, and we highlight potential priorities for future work. The synthesis is intended to be a resource for the modelling and glacial geological community.

Gelasian stage and expected stratigraphical units having similar ages in Viet Nam

During recent years (2009-2013), International Commission on Stratigraphy (ICS) has published International Chronostratigraphic Charts with the increasing trend on the quantity of Quaternary. The lower part of Quaternary has supplemented the stage of Gelasian leading to the increasing time of Quaternary from 1,6 - 1,8 million years to 2,588 million years. In Viet Nam, geologists are currently using the time from 1,6 - 1,8 million years to present for Quaternary.In order to integrate into the international geological community, Quaternary in Viet Nam needed to be studied and added more stratigraphical units with the ages of Pliocene to fit the time of 2,588 million years. In this paper, we propose two related scientific idioms:- Exclude the upper Pleistocen of Ha Noi formation of Ha Noi depression, Ba Mieu formation (Nam Can) of Cuu Long river plain, Thach Han formation (Vo Dac) of Central of Viet Nam.In addition, detailed studies on paleontology, sedimentary, paleomagnetic, absolute age, stratigraphical events…needed to be continuously invested for implementation in the future.ReferencesIUGS ratified ICS Recommendation on redefinition of Pleistocene and formal definition of base of Quaternary, June 30th 2009. (Source: www.stratigraphy.org). Tống Dzuy Thanh và Vũ Khúc (chủ biên), 2005. Các phân vị địa tầng Việt Nam. Nhà xuất bản Đại học Quốc gia Hà Nội, 553tr. Nguyễn Địch Dỹ, 1987. Địa tầng và cổ địa lý trầm tích Kainozoi Việt Nam. Luận án Tiến sĩ Khoa học, tiếng Nga, 380tr.

PALAIOS--PRESENT AND FUTURE

After nearly eight years, I am stepping down as coeditor of PALAIOS at the end of December. Serving the paleontology and sedimentary geology communities through SEPM (Society for Sedimentary Geology) has been an honor and a privilege. During my tenure, I have been fortunate to work with coeditors Edith Taylor (2006–2011) and John-Paul Zonneveld (2011–present), as well as welcoming coeditor Thomas Olszewski—who has been serving PALAIOS as an associate editor—to the editorial team as my replacement. I have learned much from them through their scientific specialties, insights into evaluating research submitted for consideration, and ability to discuss reviews and aspects of manuscripts under peer review so that we can arrive at compromise on editorial decisions. Jill Hardesty has taught me much on the day-to-day responsibilities of the review and editorial processes, as well as the value of maintaining high standards of journal editing. She has been the engine driving the continued success of PALAIOS as managing editor by receiving, reviewing, and dispensing review invitations, manuscripts, reviews, and communications between the authors, reviewers, associate editors, and coeditors. I have also learned so much from you, our contributing authors, about the great variety of multidisciplinary, integrative research being conducted worldwide and its applications to answering geological and paleontological questions recorded in Archean, Proterozoic, and Phanerozoic sedimentary deposits. I hope that I have also had a positive influence on all those who have submitted and published their research in PALAIOS . In my final Spotlight as coeditor, I share my reflections on serving as an editor and the role of PALAIOS as an outlet for publishing the highest quality, refereed science at the interface of the disciplines that are contained within sedimentary geology and paleontology. The goal of a journal, which should be shared by all involved in the peer-review, editing, and publication …

Temperature Induced Internal Stress in Carrara Marble

Stone physical weathering, deterioration and damage (e.g. bowing, cracking, microfracturing) represent a serious problem for preservation of sculptural and architectural heritage objects. Although different mechanisms of such degradation might be responsible (e.g. chemical or biogenic), there is an understanding in the geological community that physical reasons for stone degradation and role of stress are of primary importance. In this work Carrara marble was a chosen for investigation: a calcitic type with ~20% of dolomite. Neutron diffraction was used to investigate the phase composition, the texture, and the strain/stress in calcite and dolomite phases in a bulk marble sample. Evolution of the stress state was studied by measuring strains in calcite and dolomite at two temperatures with clear evidence of thermally induced microstresses. Results are discussed in connection to the theory of composite materials and a micro-mechanical explanation of the general problem of marble deterioration is suggested.

The criticality of metals: a perspective for geologists

Abstract The criticality of metals (the quality, state, or degree of being of the highest importance) is of increasing concern as populations and wealth increase and as mineral extraction follows. Many characteristics are involved in determining criticality, and those involving geology are among the most important. We discuss the state of knowledge of mineable resources across the periodic table, and how those determinations factor into criticality evaluations. We then illustrate criticality evaluations of the copper ore group elements for the specific example of the UK. Given the importance of the ore metals over the long term, we argue that efforts on the part of the geological community to update and maintain criticality-related information deserve much more attention than they are now receiving.

The Brazilian Journal of Geology is born. Long life to it!

For the members of the geological community of Brazil, the Revista Brasileira de Geociencias (RBG) has been the most obvious locus to submit their scientific contributions for more than 40 years. With Volume 43, RBG changes not only its title and graphical project, but mainly its focus as it seeks to establish itself among the best international publications in the Earth Sciences. With an open-access electronic version, the Brazilian Journal of Geology (BJG) provides an international medium and a regional reference for publication of matters concerned with all aspects of Geological Sciences in Brazil, neighboring countries and the South Atlantic in general, including Antarctica.

Local communities and young people – the future of geoconservation

Abstract The UK has weakening development controls, limited earth science teaching and reducing financial resources which directly impact the geological community's ability to sustain the conservation of local geodiversity. Geoconservation is becoming a function of interested local people's desire to do something rather than having a formal mandate and paradoxically it is non-geologists who are often best placed to do the practical conservation. Fewer younger people are getting involved in geoconservation which is particularly worrying for the future. Local geology needs to be meaningful and personal to a much wider range of people if we are to achieve a sustained geoconservation outcome. There is a fantastic array of local geodiversity assets to engage new people but perhaps we need to use them in exciting new ways in order to succeed. This paper focuses on some inspirational projects that have engaged local communities and younger people in the Black Country, England, UK.