Lawrence H Tanner

Lawrence H Tanner
Le Moyne College · Environmental Science Systems

PhD

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155
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Publications

Publications (155)
Article
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The Skaftafellsjökull is an outlet glacier in southern Iceland that has been retreating since 1890. While multiple studies have examined primary succession on the foreland of this glacier, no study has examined the distribution of woody biomass on the outwash plain. We investigated the distribution of one species, Betula pubescens, that grows on th...
Article
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One of the more visible consequences of anthropogenic climate change is the ongoing retreat of glaciers worldwide. Rates of primary succession in the resulting glacial forelands are commonly calculated from a single measurement set using a single set of measurements across a landscape of varying age, but repeated measurements over decadal scales ma...
Article
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The lithofacies, microfacies, and depositional environments of the Dhruma Formation were studied at the type locality at Khashm adh Dhibi to better understand the sedimentology and depositional history on the Arabian Platform. Twelve lithofacies were identified that can be grouped into four lithofacies associations corresponding to depositional pal...
Article
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Recent anthropogenic climate change has caused both glacial retreat and increased vegetative growth on Arctic and subarctic tundra landscapes resulting in changing albedo and energy budgets. Glacial forelands are topographically and ecologically heterogeneous landscapes comprising ice-contact and outwash deposits subject to primary succession. The...
Article
This study provides a detailed examination of a condensed Cenomanian-Turonian (C-T) succession of two sections (Dokan Dam and Khalakan) in the Kurdistan Region, Northeastern Iraq, based on biostratigraphy (calcareous nannofossils and planktic foraminifera), carbon and oxygen isotope geochemistry, and facies analysis. The C/T boundary in this region...
Article
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The mass extinction at the Cretaceous‐Palaeogene boundary is widely attributed to sudden and severe climate changes forced by bolide impact and/or flood basalt volcanism. In terrestrial depositional settings, these changes may potentially be recorded by palaeosols. To test the ability of pedogenic features to record both long‐term climate and short...
Article
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Background The forelands of retreating glaciers are invaluable natural laboratories in which to explore the processes of primary succession. Numerous studies have been conducted on foreland chronosequences to identify temporal and spatial trends of the successional communities. This study focused on the spatio-temporal distribution of three woody p...
Article
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We document calcareous paleosols from Upper Pennsylvanian (lower Virgilian) strata of the Burrego Member of the Atrasado Formation in the Cerros de Amado of Socorro County, New Mexico. The Burrego paleosols are an excellent example of a scarce, climate-sensitive lithology in the Pennsylvanian strata of New Mexico. These paleosols contain mostly sta...
Article
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Anomalous levels of iridium in sedimentary strata are associated with mass extinction events caused by impact events. In the case of the end-Triassic extinction event, the anomalies as well as the extinctions are linked to the eruption of the Central Atlantic Magmatic Province (CAMP) flood basalts. We report new data on concentrations of iridium in...
Chapter
The use of the carbon isotope composition (δ¹³C) of pedogenic calcite as a proxy for pCO2 was established over three decades ago and remains a primary means of investigating climate history. Over time, an increased understanding of the systematics of pedogenic carbonate precipitation has improved the constraints on interpreting paleoatmospheric com...
Article
The latest Triassic was an interval of prolonged biotic extinction culminating in the end-Triassic Extinction (ETE). The ETE is now associated with a perturbation of the global carbon cycle just before the end of the Triassic that has been attributed to the extensive volcanism of the Circum-Atlantic Magmatic Province (CAMP). However, we attribute t...
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Abstract Introduction Primary succession on glacial forelands is increasingly relevant as rapid glacial retreat is exposing growing land areas to plant colonization. We investigated temporal trends, controls, and outcomes in floral succession on a subarctic glacial foreland. Specifically, we examined changes in community composition (mosses, low sh...
Conference Paper
Full-text available
Use of the stable isotopic composition of pedogenic calcite, both δ 13 C and δ 18 O, as proxies for paleoclimate was established over three decades ago and remains a primary means of investigating climate history. Over time, an increased understanding of the systematics of pedogenic carbonate precipitation has improved the constraints on interpreti...
Conference Paper
Full-text available
The latest Triassic was an interval of prolonged biotic extinction culminated by the end-Triassic Extinction, which is associated with a pronounced perturbation of the global carbon cycle that can be connected to extensive volcanism of the Central Atlantic Magmatic Province (CAMP). Earlier chaotic perturbations of the global carbon cycle can also b...
Article
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Soil organic matter (SOM) is a major reservoir of carbon derived from the biosphere that is returned to the atmosphere largely via microbial decomposition. The potential for feedbacks between climate change and SOM decomposition makes a full understanding of the controls on SOM decomposition rates essential to modeling future climate changes. We me...
Article
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Studies have documented that recent anthropogenic climate change has caused increased vegetative growth on arctic tundra landscapes, resulting in increased carbon storage (in biomass and soil), but decreased albedo and increased energy budgets. The glacial outwash sandplains (sandurs) of Iceland offer an interesting landscape comparison. Here, glac...
Conference Paper
Full-text available
The Late Triassic was a time of elevated extinction rates and low origination rates marked by a series of discrete extinction events. One of the most dramatic was the "Carnian crisis" close to the early-middle Carnian boundary, which included major extinctions of crinoids, echinoids, some bivalves (scallops), bryozoans, ammonoids, conodonts and a m...
Chapter
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The Late Triassic (Carnian to Rhaetian Stages: ca. 237–201 Ma) has a long history of geological research, although controversy remains over the precise definition of key sub-unit boundaries, including those defining the three constituent stages. Within this context, at least five terrestrial bolide impact structures ranging from 9 to 85 km in diame...
Chapter
The Late Triassic was a prolonged episode characterized by high rates of biotic turnover and discrete extinction events due to elevated extinction rates for some biotic groups and low origination rates for many. An end-Triassic mass extinction continues to be cited as one of the “big five” mass extinctions of the Phanerozoic. However, a detailed ex...
Chapter
The majority of paleoclimate evidence, including climate-sensitive lithofacies, paleobotanical evidence and a lack of evidence of glaciation, indicates a climate that was significantly warmer during the Late Triassic than at present. Multiple proxies demonstrate higher atmospheric pCO2 during the Late Triassic as the driver for this warmth. Histori...
Article
Two new chemical abrasion thermal ionization mass spectrometry U/Pb dates establish the age of the top of the Brushy Basin Member, Morrison Formation, at Flat Top (also known as Terrace Hill), north of the Fruita Paleontological Research Natural Area (FP), and of the lower part of the Brushy Basin Member, in the region of the Trail through Time (TT...
Article
The Late Triassic Carnian wet episode was an interval of humid climate evident in the lowermost strata of the Upper Triassic Chinle Group in the western USA. Chinle deposition began with the development of major river systems of the Shinarump Formation and equivalents, laterally equivalent to and/or overlain by floodplain deposits containing kaolin...
Article
The Upper Pennsylvanian to lowermost Permian El Cobre Canyon and Arroyo del Agua formations are well exposed in a 250+ m section in the Chama Basin in northern New Mexico. This is one of the few known successions of fossiliferous red-bed siliciclastic sediments encompassing the Pennsylvanian-Permian boundary in the American Southwest and thus may i...
Book
This volume presents the latest science on all significant geological and paleontological aspects of the Earth during the Late Triassic Period. Rather than presenting a collection of narrowly focused research papers, the volume consists of a series of peer-reviewed chapters on specific aspects of the Late Triassic world (e.g., tectonics, magmatism,...
Article
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The lower Permian (Wolfcampian) Sangre de Cristo Formation of northern New Mexico consists of silty mudstones and laterally discontinuous sandstones deposited on an aggrading alluvial plain. Locally, mudstones display a variety of pedogenic features. Common mudstone fabrics vary from platy to prismatic; some beds display prominent pedogenic slicken...
Article
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Carbonate lithofacies of the lower member of the El Hefhuf Formation (Turonian, Coniasian-Santonian) in the Bahariya Oases, Western Desert of Egypt comprise dolostone, burrowed dolostone, cherty dolostone, calcareous dedolostone, dolomitic quartzose lime-mudstone, and caliche,. The dolostone and cherty dolostone formed in intertidal to supratidal e...
Article
We document the occurrence of Upper Triassic fusain in northern Arizona, southern Utah and northern New Mexico in latest Carnian(?) to Norian-age alluvial strata of the Monitor Butte Formation and the Sonsela and Painted Desert members of the Petrified Forest Formation (Chinle Group). The fusain, identified by standard techniques of macroscopic and...
Article
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We measured carbon stocks at two forest reserves in the cloud forest region of Monteverde, comparing cleared land, experimental secondary forest plots, and mature forest at each location to assess the effectiveness of reforestation in sequestering biomass and soil carbon. The biomass carbon stock measured in the mature forest at the Monteverde Inst...
Article
Samples from strata spanning the Triassic-Jurassic boundary at the GSSP at Kuhjoch and at Kendlbachgraben were studied by NAA, XRF and combustion analysis to determine Ir levels and associated geochemistry. The results are compared to previously determined carbon isotope stratigraphy at these sections. Ir concentrations in the limestones of the Kös...
Article
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The Upper Permian? - Lower Jurassic Newark Supergroup of eastern North America has a strikingly uniform succession of lithologic units. This uniformity is seen regardless of whether these units are characterized on the basis of their lithostratigraphy, allostratigraphy, biostratigraphy, or chemostratigraphy. After deposition, these units were broke...
Article
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The Late Triassic was a prolonged interval of elevated extinction rates and low origination rates that manifested themselves in a series of extinctions during Carnian, Norian and Rhaetian time. Most of these extinctions took place in the marine realm, particularly affecting radiolarians, conodonts, bivalves, ammonoids and reef-building organisms. O...
Article
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In southwestern San Miguel County, New Mexico, the upper Paleozoic Sangre de Cristo Formation is ~300 m thick. Most of the lower-middle parts of the formation are poorly exposed, but the base of the formation crops out as extrabasinal conglomerate resting with evident disconformity on the Middle Pennsylvanian Porvenir Formation. The upper 160 m of...
Article
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Experimental plots were established on severely eroded land surfaces in Iceland in 1999 to study the rates and limits of soil carbon sequestration during restoration and succession. The carbon content in the upper 10 cm of soils increased substantially during the initial eight years in all plots for which the treatments included both fertilizer and...
Article
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Spectral analyses of apparent cyclicity of Triassic-Jurassic strata in the Newark Basin (New Jersey, USA) have been used to generate peak recurrence intervals within the sequence. When calibrated to sedimentation rates derived from varve counts in lacustrine mudstones, these recurrence intervals yield cycles inferred to correspond to orbital forcin...
Article
Natural molds of 165 stems were found in life position in a 1 m-thick sandstone bed, lower Permian (Wolfcampian), Sangre de Cristo Formation, northern New Mexico. The sandstone represents a single flood event of a river sourced in the Ancestral Rocky Mountains. Most of the flood-buried plants survived and resumed growth. The stem affinities are unc...
Conference Paper
Full-text available
in southwestern San Miguel County, New Mexico, the upper Paleozoic Sangre de Cristo Formation is ~300 m thick. Most of the lower-middle parts of the formation are poorly exposed, but the base of the formation crops out as extrabasinal conglomerate resting with evident disconformity on the Middle Pennsylvanian Porvenir Formation. The upper 160 m of...
Article
Full-text available
Study of the pedogenic features of the Upper Jurassic Morrison Formation in western Colorado, USA, shows a clear difference in the types of paleosols between the strata of the lower and upper Brushy Basin Member. Lower Brushy Basin paleosols are mostly calcareous Aridisols with Stage I through Stage III calcrete Bk horizons, abundant root traces, o...
Article
Full-text available
Study of the pedogenic features of the Upper Jurassic Morrison Formation in western Colorado, USA, shows a clear difference in the types of paleosols between the strata of the lower and upper Brushy Basin Member. Lower Brushy Basin paleosols are mostly calcareous Aridisols with Stage I through Stage III calcrete Bk horizons, abundant root traces, o...
Chapter
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An astronomically tuned timescale has been applied successfully to most of the Cenozoic record, but remains problematic for much of the Mesozoic. We examine the reliability of the cyclostratigraphy of the Upper Triassic of the Newark basin and find that a strict application of an astronomic timescale is contradicted by biostratigraphy. The greatest...
Article
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The biochronology based on the global biostratigraphy of tetrapod fos-sils allows the Triassic System to be divided into eight land-vertebrate faunachrons based mainly on the first appearance datums of tetrapod genera. Temporal reso-lution may be improved by subdivision of these faunachrons. We note, however, that this biochronology is undermined b...
Chapter
The biochronology based on the global biostratigraphy of tetrapod fossils allows the Triassic System to be divided into eight land-vertebrate faunachrons based mainly on the first appearance datums of tetrapod genera. Temporal resolution may be improved by subdivision of these faunachrons. We note, however, that this biochronology is undermined by...
Chapter
An astronomically tuned timescale has been applied successfully to most of the Cenozoic record, but remains problematic for much of the Mesozoic. We examine the reliability of the cyclostratigraphy of the Upper Triassic of the Newark basin and find that a strict application of an astronomic timescale is contradicted by biostratigraphy. The greatest...
Article
Full-text available
Received December 31 st , 2013; revised January 31 st , 2014; accepted February 7 th , 2014 Copyright © 2014 Lawrence H. Tanner et al. This is an open access article distributed under the Creative Commons Attribution Li-cense, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited....
Chapter
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The current Triassic chronostratigraphic scale is a hierarchy of three series (Lower, Middle, and Upper) divided into seven stages (Lower = Induan and Olenekian; Middle = Anisian and Ladinian; and Upper = Carnian, Norian, and Rhaetian), further divided into 15 substages (Induan = upper Griesbachian and Dienerian; Olenekian = Smithian and Spathian;...
Data
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The land surface in front of the Skaftafellsjökull in southern Iceland, exposed by ice recession commencing about the start of the twentieth century, constitutes a foreland with a maximum age of about 100 years and a more distal outwash plain. The ages of different surfaces within this sequence are constrained by moraines of known or estimated ages...
Data
Full-text available
Abstract—The most distinctive feature of the Upper Triassic (Carnian) Quaco Formation, coastal New Brunswick, Canada, is the pervasive occurrence of cm-scale circular to elliptical markings and indentations on the cobble surfaces. Also present on many of the cobbles are fractures that radiate from these indentations and spalled clast margins. The s...
Article
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Carbonates of the Ojo Huelos Member of the San Pedro Arroyo Formation include ostracodal lime-stones, brecciated micritic limestones, vuggy, mottled limestones, peloidal graistones/packstones, pisolitic rudstones and nodular limestones. These lithofacies record deposition in lacustrine, palustrine and alluvial environments. Lacustrine (ostracodal)...
Article
Full-text available
The most distinctive feature of the Upper Triassic (Carnian) Quaco Formation, coastal New Brunswick, Canada, is the pervasive occurrence of cm-scale circular to elliptical markings and indentations on the cobble surfaces. Also present on many of the cobbles are fractures that radiate from these indentations and spalled clast margins. The smooth-sur...
Article
Full-text available
Permineralized wood from the middle of the Upper Triassic Petrified Forest Formation in Arizona, in strata correlative with the Sonsela Member, displays various forms of heartwood degradation. Pitting of the wood exhibits two primary morphologies. Elongated cavities are up to several mm long, parallel to the wood grain and may merge to form channel...
Article
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A spectacular example of columnar-jointed basalt occurs at Svartifoss in the Vatnaj¨okull National Park of southern Iceland. The columns are notable for a variety of features on the vertical joint surfaces and the horizontal parting surfaces.The jointed surfaces of the columns display horizontal striations at a spacing of centimeters to decimeters....
Article
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A tetrapod trackway from the Lower Pennsylvanian at the historic section at Joggins, Nova Scotia, preserves 13 pairs of impressions with a possible partial tail drag. Although overstepping and poor preservation obscure many of the diagnostic features, the pes is plantigrade to semi-plantigrade and distinctly pentadactyl, with digit length increasin...
Article
The Upper Triassic (Adamanian LVF) Ojo Huelos Member of the San Pedro Arroyo Formation (Chinle Group) is a distinctive, carbonate-rich unit that occurs in the lower Chinle section of central New Mexico. The mem-ber consists mainly of micritic lime mudstones, ostracodal wackestones to grainstones, peloidal grainstones and distinctive pisolitic rudst...
Article
The Late Triassic timescale is poorly constrained due largely to the dearth of reliable radioisotopic ages that can be related precisely to biostratigraphy combined with evident contradictions between biostratigraphic and magnetostratigraphic correlations. These problems are most apparent with regard to the age and corre-lation of the Carnian–Noria...
Article
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The Yan'an Formation of the Ordos Basin is a sequence of four members, consisting of siliciclastic sediments deposited in alluvial, lacustrine and mire settings during the Middle Jurassic. Samples collected from Members Two and Four contain abundant blackened plant material identified through standard analytical techniques as fusain (fossil charcoa...
Article
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New major and trace element data and 40Ar/39Ar plateau ages constrain the timing, duration and time-related geochemical evolution of the Central Atlantic magmatic province in the U.S.A. (Newark and Culpeper basins) and refine correlations with basaltic lava flows from other Late Triassic-Early Jurassic circum-Atlantic basins. The precise, statistic...
Article
Strata of the Moenave Formation on and adjacent to the southern Colorado Plateau in Utah–Arizona, U.S.A., represent one of the best known and most stratigraphically continuous, complete and fossiliferous terrestrial sections across the Triassic–Jurassic boundary. We present a synthesis of new biostratigraphic and magnetostratigraphic data collected...
Article
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n this paper we present a model for the growth of a maar-diatreme complex in a shallow marine environ- ment. The Miocene-age Costa Giardini diatreme near Sortino, in the region of the Iblei Mountains of southern Sicily, has an outer tuff ring formed by the accumulation of debris flows and surge deposits during hydromagmatic eruptions. Vesicular lav...
Article
The formation of carbonate sediments in continental environments is subject to numerous environmental controls, of which climate is one of the foremost. Consequently, calcareous paleosols and lacustrine, palustrine, speleothem, and tufa carbonates all have been found particularly useful as paleoclimate proxies. Calcareous paleosols, for example, ar...
Article
Full-text available
Strata of the Moenave Formation on and adjacent to the southern Colorado Plateau in Utah-Arizona, USA represent one of the best known and most stratigraphically continuous, complete and fossiliferous terrestrial sections across the Triassic-Jurassic boundary. We present here a synthesis of new biostratigraphic and magnetostratigraphic data collecte...