Bedrock Geologic Map of the Northern Half of the Bedford 30- X 60-Minute Quadrangle, Indiana

The Bedrock Geologic Map of the Northern Half of the Bedford 30- X 60-Minute Quadrangle is an Esri File Geodatabase that contains six feature data sets, five geodatabase tables, and two raster data sets detailing the bedrock geology of the northern half of the Bedford 30- X 60-minute quadrangle in Indiana. This data set conforms to "GeMS (Geologic Map Schema)--a standard format for the digital publication of geologic maps." For more information on GeMS please refer to the supplemental information within this metadata.

August Tobler, the Swiss Pioneer of South Sumatra Geological Mapping, 1900-1912

Dr. August Tobler was a well-known Swiss geologist, who, as one of the very first petroleum field geologists in the Netherlands Indies, did more than ten years of geological mapping in the tiger-infested jungles of South Sumatra. He first worked for the Koninklijke/Royal Dutch and Moeara Enim oil companies in South Sumatra from 1900 to 1904. This was followed by six more years of geological mapping in the Jambi basin, as the first non-Dutch geoscientist at the Dienst van het Mijnwezen (Geological Survey). His thoroughly documented monographs and geologic maps of his geological fieldwork in the Palembang and Jambi basins of South Sumatra, as well as the adjacent Barisan Mountains, set new standards for quality and detail.Much of the personal information on Dr. Tobler is from papers by Kugler (1930, 1963), Oppenoorth (1930), Stehlin (1931) and Hottinger (2013). This paper is one of the chapters from a new book that is being prepared by the first author, entitled Pioneers and Milestones of Indonesian Geology (~1820-1960).

Geologic Time

Geologists first unraveled the geologic time scale by relative age-dating, discussed in the last chapter. Once geologists sorted out the order of rock units, subsequent advances in methodologies, detailed in this chapter, by chronometric and numerical means based on radioisotopes, other atomic measures, and quantitative techniques, were employed to measure time. Many minerals and rocks have “clocks” within them that can be used to pin down the actual age of the particular geologic sample or the age of boundaries between formal units of the geologic time scale. This chapter explains how geologists decipher those clocks and determine the ages of rocks by numerical age-dating. The history of radioisotopes is tracked, starting with Ernest Rutherford and Pierre and Marie Curie. The modern geologic time scale is depicted and expanded upon, along with why it is essential for geologic maps and how the time scale can help with people-sized problems and challenges faced on the Earth.

Supplemental Material: Mapping Critical Minerals from The Sky

Item S1: Listing and index of geologic maps used in images and statistical analyses with age correlations for different map unit definitions. Item S2: Visual heavy mineral sand and phosphate content for over 1000 auger samples collected during previous mapping efforts. Item S3: Heavy mineral sand weight percent and economic mineral grade and tonnage estimates by Force et al. (1982) with overlays of sample positions on the new data. Item S4: Radiometric eTh, eU, and K draped over lidar (three PDF files).

Supplemental Material: Mapping Critical Minerals from The Sky

Item S1: Listing and index of geologic maps used in images and statistical analyses with age correlations for different map unit definitions. Item S2: Visual heavy mineral sand and phosphate content for over 1000 auger samples collected during previous mapping efforts. Item S3: Heavy mineral sand weight percent and economic mineral grade and tonnage estimates by Force et al. (1982) with overlays of sample positions on the new data. Item S4: Radiometric eTh, eU, and K draped over lidar (three PDF files).

Gobi Altai, Khangai and Khentii Mountains mapped by a mixed-method cartographic approach for comparative geophysical analysis

Geologic and geophysical mapping has been so far limited to the traditional single-method GIS-based mapping. A new approach combining integrated analysis of data on geology, gravity, topography and geomorphology is presented for regional characterization of the geophysical setting in Mongolia: the Gobi Altai Mountains, the Khangai Mountains and Khentii Mountains with surrounding areas. Nine new maps have been produced from the high-resolution datasets: GEBCO, gravity raster, USGS geological data and SRTM-90 DEM geomorphological grid. Methodology includes three tools for cartographic data visualization: i) Generic Mapping Tools (GMT), ii) R programming language (‘raster’ and ‘tmap’ libraries); iii) QGIS. The results demonstrated strong agreement between the estimated values in gravity and topography grids, distribution of geological units and provinces over the country and geomorphological landforms with respect to the mountain ranges: Altai, Khangai and Khentii Mountains. The highest values in the gravity anomalies correspond to the mountain ranges in the Altai Mountains and Khangai Mountains (<80 mGal); high values correspond to the Khentii Mountains (20–60 mGal). Contrariwise, the basins of the Uvs Nuur and Khyargas Nuur show negative values (<-80 mGal). The NE- to NNE-oriented faulting and rift basins are clearly visible in the geophysical grids and geologic maps. The geomorphometric analysis performed based on the SRTM-90 DEM using R scripting demonstrated (1) slope, (2) aspect, (3) hillshade and (4) elevation models of Mongolia supported by histograms of data distribution and frequency. The study contributed to the cartographic methods and regional geological studies of Mongolia.

Geology of southeastern Barbados

ABSTRACT This chapter presents geological documentation of Quaternary (and perhaps older) event histories of southeastern Barbados. The Barbados Limestone is herein formally defined. A time-stratigraphic division of the Barbados Limestone in southeastern Barbados and the properties of the stratigraphic units are presented. A major finding of this study is that the marine terraces originated wholly by marine erosion, not by reef construction, and evolved in stages over a long duration. The hydrology and thickness data of the Barbados Limestone are discussed, and hypotheses on causes of thickness variations are given. The study domain is divided into seven areas that contain a continuous flight of nine marine terraces preserved in various partial sequences. Discussions of these key seven areas in southeastern Barbados are supported by geologic maps at large scale and cross sections. Sections with VE &gt; 1 display limestone stratigraphy and facies over relatively large lengths. Sections with VE = 1 show true structural configurations over short lengths. Detailed observations and radioisotopic dating of the limestone units permit differentiation and correlation among them.

A statistical framework to analyse the stratigraphy of glaciofluvial terraces from topographic data

&lt;p&gt;Alluvial staircase terraces are typical Quaternary features of mid- to high latitude rivers. Their formation is linked to i) repeated events of increased sediment production, triggered by Quaternary climatic fluctuations and ii) tectonic uplift. Accordingly, terraces may act as important terrestrial archives of climatic and geodynamic information. &amp;#160;Comprehensive stratigraphic and topographic data qualifies the North Alpine Foreland as an ideal study region. Even though it has been subject to extensive investigations for more than a century consistent, basin wide stratigraphic models have not been proposed for more than a century (Penck and Br&amp;#252;ckner, 1909). Advances in local stratigraphy created major stratigraphic inconsistencies between the related parts of Switzerland, Germany and Austria.&lt;/p&gt;&lt;p&gt;In an aim to resolve these inconsistences we focus on foreland-wide high-resolution topographic data by investigating syn- and postdepositional signals behind the hypsometry and morphology of tributary terraces to the rivers Rhine and Danube.&lt;/p&gt;&lt;p&gt;By utilizing data from digital elevation models, geologic maps as well as outcrop information, morphostratigraphic analyses are provided via a new toolset within the framework of the software R. Semiautomatic projection of terrace data on 2D profiles allow to perform statistical analysis (based on slope, relative heights, concavity) of river long profiles and terrace-tops. We show that extracted parameters are highly suitable to make quantitative statements on fluvio-, glacio- and geodynamic processes controlling Quaternary terrace formation.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;Penck, A., &amp; Br&amp;#252;ckner, E. (1909). Die Alpen im Eiszeitalter. Leipzig: Tauchnitz.&lt;/p&gt;

Controls on Streamflow Densities in Semiarid Rocky Mountain Catchments

Developing accurate stream maps requires both an improved understanding of the drivers of streamflow spatial patterns and field verification. This study examined streamflow locations in three semiarid catchments across an elevation gradient in the Colorado Front Range, USA. The locations of surface flow throughout each channel network were mapped in the field and used to compute active drainage densities. Field surveys of active flow were compared to National Hydrography Dataset High Resolution (NHD HR) flowlines, digital topographic data, and geologic maps. The length of active flow declined with stream discharge in each of the catchments, with the greatest decline in the driest catchment. Of the tributaries that did not dry completely, 60% had stable flow heads and the remaining tributaries had flow heads that moved downstream with drying. The flow heads were initiated at mean contributing areas of 0.1 km2 at the lowest elevation catchment and 0.5 km2 at the highest elevation catchment, leading to active drainage densities that declined with elevation and snow persistence. The field mapped drainage densities were less than half the drainage densities that were represented using NHD HR. Geologic structures influenced the flow locations, with multiple flow heads initiated along faults and some tributaries following either fault lines or lithologic contacts.

Using strontium isotopes to determine philopatry and dispersal in primates: a case study from Kibale National Park

Strontium isotope ratios ( 87 Sr/ 86 Sr) allow researchers to track changes in mobility throughout an animal's life and could theoretically be used to reconstruct sex-biases in philopatry and dispersal patterns in primates. Dispersal patterns are a life-history variable that correlate with numerous aspects of behaviour and socio-ecology that are elusive in the fossil record. The present study demonstrates that the standard archaeological method used to differentiate between ‘local’ and ‘non-local’ individuals, which involves comparing faunal isotopic ratios with environmental isotopic minima and maxima, is not always reliable; aspects of primate behaviour, local environments, geologic heterogeneity and the availability of detailed geologic maps may compromise its utility in certain situations. This study instead introduces a different methodological approach: calculating offset values to compare 87 Sr/ 86 Sr of teeth with that of bone or local environments. We demonstrate this method's effectiveness using data from five species of primates, including chimpanzees, from Kibale National Park, Uganda. Tooth-to-bone offsets reliably indicate sex-biases in dispersal for primates with small home ranges while tooth-to-environment offset comparisons are more reliable for primates with larger home ranges. Overall, tooth-to-environment offsets yield the most reliable predictions of species' sex-biases in dispersal.