Late Quaternary geologic history of New Jersey middle and outer continental shelf

textAnalysis of high-resolution (1-4 kHz) seismic chirp profiles of the New Jersey mid-outer continental shelf, coupled with sediment samples, reveal the stratigraphic architecture resulting from the last glacio-eustatic cycle: dendritic (fluvial?) channel systems truncated by a transgressive ravinement. Quantitative geomorphologic analysis of these systems provides estimates of paleo-hydrologic parameters needed to link channel morphology to the hydrodynamic setting when these systems were active. These channels were presumably fluvial systems developed on a subaerial shelf during the Last Glacial Maximum (LGM), ~22-20 ka. During ensuing Holocene sea-level rise, these fluvial channels became estuarine/tidal, before erosion and final burial. Mean tidal paleoflow estimates for these systems with flow velocities of 1.0-1.5 m/s and shear stresses sufficient to initiate transport of grains 2-8 mm in diameter (i.e., coarse sand and fine gravel) as bed-load, are consistent with modern tidal creeks of the same dimensions. However, paleo-flow estimates, assuming a fluvial environment with velocities of 1.1-2.0 m/s, and retrodicted fluvial discharge and boundary shear stresses would have been sufficient to transport particles up to ~15 mm in diameter (i.e., gravel) as bed-load. We suggest that either the fluvial drainages never reached equilibrium during high-discharge flows, perhaps due to melt-water pulses following the LGM, or that tidal influences have modified the original fluvial geometry. Imaged and sampled channel-fills reveal a retrogradational shift of four sedimentary facies, in ascending order: 1) fluvial lags, SF1, 2) estuarine mixed sand and muds, SF2, (3) estuary central bay muds, SF3, and 4) redistributed estuary mouth sands, SF4. Three intra-fill transgressive surfaces, B1-3, interpreted as bay flooding surface, intermediate flooding surface and tidal ravinement, respectively, are also either wholly or partly preserved. My study demonstrates that wave- and tide-dominated facies can coexist within channel fills. These fill units are truncated by a morphologic irregular, transgressive wave ravinement surface, the Thorizon, which, in turn, is overlain by Holocene marine sand deposits. A ~10 m bathymetric rise in T forms both the mid-shelf scarp and the base of a smaller Holocene wedge. The modern seafloor of the New Jersey shelf experiences post-transgressive erosion, which is variously expressed.Geological Science

Key Lessons from Tailoring Agile Methods for Large-Scale Software Development

We describe advice derived from one of the largest development programs in Norway, where twelve Scrum teams combined agile practices with traditional project management. The Perform program delivered 12 releases over a four-year period, and finished on budget and on time. In this article, we summarize 12 key lessons on five crucial topics, relevant to other large development projects seeking to combine Scrum with traditional project management.Comment: Accepted for publication in IEEE IT Professiona

Geomorphological and stratigraphic evolution of a fluvial incision in the coastal plain and inner continental shelf in southern Brazil

This paper describes the evolution of a sector of the southern coastal plain of the Pelotas Basin, southern Brazil, between the last Pleistocene sea-level lowstand and the Holocene highstand, based on geomorphology and high-resolution stratigraphy. A fluvial drainage system associated with an incised valley developed during the Last Glacial Maximum (LGM) was identified. Two highresolution 2D and 2.5D geophysical profiles using Ground-Penetrating Radar (GPR) show a Pleistocene fluvial system's former path, starting close to its present mouth inside Mirim Lagoon crossing the coastal barriers and reaching the inner continental shelf, covering some 60 km across the coastal plain. During the LGM, with the sea-level at −120 to −130 m and the coastline positioned close to the shelf edge (distant 200 km from the present coastline), the fluvial system excavated a ~31.5-m deep channel. Two cores, 36 and 32 m long, show that the paleochannel was filled with sedimentary deposits after 19.4 ka BP, and the facies succession represents the transition from fluvial, to estuarine, to the coastal barrier, and finally to inner shelf depositional environments, generated by processes connected to LGM and the Postglacial Marine Transgression (PMT). The study region behaved as a sediment by-pass zone, connecting the adjacent coastal plain's inner portion with the inner continental shelf. The studied area presents an unusual record of the LGM at a coastal plain domain

Incised valley paleoenvironments interpreted by seismic stratigraphic approach in Patos Lagoon, Southern Brazil

<div><p>ABSTRACT: The Rio Grande do Sul (RS) coastal plain area (33,000 km 2 ) had its physiography modified several times through the Quaternary, responding to allogenic and autogenic forcings. The Patos Lagoon covers a significant area of RS coastal plain (10,000 km 2 ), where incised valleys were identified in previous works. About 1,000 km of high resolution (3.5 kHz) seismic profiles, radiocarbon datings, Standard Penetration Test (SPT) and gravity cores were analyzed to interpret the paleoenvironmental evolution as preserved in incised valley infills. Seismic facies were recognized by seismic parameters. The sediment cores were used to ground-truth the seismic interpretations and help in the paleoenvironmental identification. Key surfaces were established to detail the stratigraphical framework, and seismic facies were grouped into four seismic units, which one classified in respective system tracts within three depositional sequences. The oldest preserved deposits are predominantly fluvial and estuarine facies, representing the falling stage and lowstand system tracts. The Holocene transgressive records are dominated by muddy material, mainly represented by estuarine facies with local variations. The transgression culminated in Late Holocene deposits of Patos Lagoon, representing the highstand system tract. The depositional pattern of the vertical succession was controlled by eustatic variations, while the autogenic forcing (paleogeography and sediment supply) modulated the local facies variation.</p></div

The role of discharge variability in the formation and preservation of alluvial sediment bodies

Extant, planform-based facies models for alluvial deposits are not fully fit for purpose, because they over-emphasise plan form whereas there is little in the alluvial rock record that is distinctive of any particular planform, and because the planform of individual rivers vary in both time and space. Accordingly, existing facies models have limited predictive capability. In this paper, we explore the role of inter-annual peak discharge variability as a possible control on the character of the preserved alluvial record. Data from a suite of modern rivers, for which long-term gauging records are available, and for which there are published descriptions of subsurface sedimentary architecture, are analysed. The selected rivers are categorized according to their variance in peak discharge or the coefficient of variation (CVQp = standard deviation of the annual peak flood discharge over the mean annual peak flood discharge). This parameter ranges over the rivers studied between 0.18 and 1.22, allowing classification of rivers as having very low ( 0.90) annual peak discharge variance. Deposits of rivers with very low and low peak discharge variability are dominated by cross-bedding on various scales and preserve macroform bedding structure, allowing the interpretation of bar construction processes. Rivers with moderate values preserve mostly cross-bedding, but records of macroform processes are in places muted and considerably modified by reworking. Rivers with high and very high values of annual peak discharge variability show a wide range of bedding structures commonly including critical and supercritical flow structures, abundant in situ trees and transported large, woody debris, and their deposits contain pedogenically modified mud partings and generally lack macroform structure. Such a facies assemblage is distinctively different from the conventional fluvial style recorded in published facies models but is widely developed both in modern and ancient alluvial deposits. This high-peak-variance style is also distinctive of rivers that are undergoing contraction in discharge over time because of the gradual annexation of the channel belt by the establishment of woody vegetation. We propose that discharge variability, both inter-annual peak variation and “flashiness” may be a more reliable basis for classifying the alluvial rock record than planform, and we provide some examples of three classes of alluvial sediment bodies (representing low, intermediate, and high/very high discharge variability) from the rock record that illustrate this point

Bærekraft i circle k norge

I min bacheloroppgave ønsket jeg å knytte Circle K Norge og bærekraft sammen og se på hvilken betydning dette har for de ansatte. Problemstillingen ble dermed: Hvilken betydning har økt fokus på bærekraftig utvikling for de ansatte i Circle K Norge? Oppgaven vil ta for seg viktigheten av å være bærekraftige både for de allerede ansatte og deres motivasjon, men også for potensielle ansatte og omdømmet til Circle K. Problemstillingen har vært utgangspunktet for oppgaven og blitt underbygd med tre underproblemstillinger som bærekraft, motivasjon og rekruttering, som også er hovedområdene for teoriinnhenting. De mest sentrale teoriene som har blitt brukt er klassisk motivasjonsteori som Maslow og ytre-/indre motivasjon, målsettingsteori, rekrutteringsprosessen og teorier og statistikk om samfunnsansvar og bærekraft. Teorifundamentet ble brukt til å forme en spørreundersøkelse og diskutere resultatene. Dataene jeg har brukt i oppgaven er samlet inn i samarbeid med ansatte på Circle K sitt hovedkontor i Oslo. Spørreundersøkelsen, som ble utført i Qualtrics, fikk 24 respondenter og all data ble analysert i Excel. Funnene i spørreundersøkelsen viser at de ansatte i Circle K Norge er mer opptatt av bærekraft personlig enn på jobb. De ansatte mener også miljøskadelig emballasje og reduksjon av matavfall er de viktigste områdene Circle K kan bli bærekraftige på. Det er mulige psykologiske barrierer som Circle K må bryte ned for å styrke den indre motivasjonen de ansatte har og dermed kan bidra til bærekraftig utvikling. Det er viktig at Circle K involverer de ansatte i målsettingen av bærekraftige for å motivere de og skape engasjement. Dette kan resultere i at bærekraft blir en naturlig del av jobbhverdagen til de ansatte og kan styrke omdømmet til Circle K