Wisconsinan stratigraphy of the Cuyahoga Valley in the Erie Basin, northeastern Ohio

1987 ◽  
Vol 24 (2) ◽  
pp. 279-290 ◽  
Author(s):  
John P. Szabo
Keyword(s):  
Clay Minerals ◽  
Carbonate Content ◽  
Glacial Erosion ◽  
Radiocarbon Dates ◽  
The Core ◽  
Lacustrine Deposits ◽  
Organic Debris ◽  
Il Y A ◽  
Proglacial Lake ◽  
Minéraux Argileux

During the Wisconsinan Stage, ice of the Cuyahoga Lobe flowed southward from the Erie Basin through a lowland created by an ancestral Cuyahoga River. The paleovalley of the Cuyahoga River is filled with the pre-Woodfordian tills and lacustrine deposits. The oldest till, the Mogadore Till, overlies proglacial lacustrine deposits. After retreat of Mogadore ice into the Erie Basin, ice readvanced to deposit a previously unnamed till, Northampton Till, over deltaic and lacustrine deposits of Lake Cuyahoga. Northampton ice melted back into the Erie Basin after depositing the core of the Summit County morainic complex. Northampton ice then readvanced over deposits of proglacial Lake Independence and formed the Defiance Moraine. Aside from minor leaching of carbonates and weathering of clay minerals, little evidence of the Farmdalian Substage exists. Woodfordian, Kent, Lavery, and Hiram tills were deposited over pre-Woodfordian deposits.The multiple nature of the pre-Woodfordian tills in the Cuyahoga Lobe is similar to that of the Titusville Till in Pennsylvania and northeastern Ohio. Northampton Till is distinctive in having a significantly different matrix texture and carbonate content from either the Mogadore or the Kent Till. Organic debris suitable for dating from pre-Woodfordian deposits is rare because of glacial erosion and drainage changes. Lack of radiocarbon dates continues to complicate the interpretation of the Pre-Woodfordian stratigraphy.Durant l'épisode wisconsinien, la glace du lobe de Cuyahoga s'écoulait vers le sud à partir du bassin Érié en traversant une plaine créée par l'ancien lit de la rivière Cuyahoga. La paléovallée de la rivière Cuyahoga est comblée de tills et de dépôts lacustres. Le till le plus ancien, Mogadore, recouvre les dépôts lacustres proglaciaires. La régression du glacier de Mogadore fut suivie d'une progression qui édifia un till, jadis sans nom, mais ultérieurement appelé le till Northampton, lequel recouvre les dépôts deltaïques et lacustres du lac Cuyahoga. Le front du glacier de Northampton recula dans le bassin Érié après y avoir déposé la partie centrale du complexe morainique de Summit County. Ensuite, le glacier de Northampton réavança et recouvrit les dépôts du lac proglaciaire Independence et y déposa la moraine Defiance. À part un lessivage mineur des carbonates et une légère altération des minéraux argileux, il y a peu d'indice de l'exitence du sous-épisode farmdalien. Les tills du Woodfordien, Kent, Lavery et Hiram furent ont été mis en place par-dessus les dépôts pré-woodfordiens.

scholarly journals Carbonate sedimentation and effects of eutrophication observed at the Kališta subaquatic springs in Lake Ohrid (Macedonia)

2010 ◽  
Vol 7 (3) ◽  
pp. 4715-4747 ◽  
Author(s):  
M. Matter ◽  
F. S. Anselmetti ◽  
B. Jordanoska ◽  
B. Wagner ◽  
M. Wessels ◽  
...  
Keyword(s):  
Sediment Traps ◽  
Authigenic Carbonate ◽  
Sidescan Sonar ◽  
Carbonate Content ◽  
Carbonate Precipitation ◽  
Lake Ohrid ◽  
Radiocarbon Dates ◽  
North West ◽  
The North ◽  
Spring Area

Abstract. To date, little is known about the role of spring waters with respect to authigenic carbonate precipitation in the shallow lacustrine setting. Lake Ohrid, located in Southeastern Europe, is a large lake fed to over 50% by karstic springs of which half enter subaquatically and influence significantly its ecology and species distribution. In order to evaluate how sedimentological processes are influenced by such shallow-water springs, the Kališta subaquatic spring area in the north west of Lake Ohrid was investigated by a sidescan sonar survey and with sediment traps and three transects of gravity short cores. Results indicate that sedimentation in the spring area is dominated by authigenic carbonate precipitation. High sedimentation rates and evidences for bio-induced precipitation processes were observed in the water column and in the sediments. Two distinct stratigraphic units characterize the shallow subsurface, both composed of carbonate silts with high carbonate contents of up to 96%, but differing in color, carbonate content and diatom content. A chronological correlation of the cores by radiocarbon dates and 137Cs activities places the transition between the two stratigraphic units after ~1955 AD. At that time, coastal sedimentation changed drastically to significantly darker sediments with higher contents of organic matter and more abundant diatoms. This change coincides with the recent human impact of littoral eutrophication.

A Paleoenvironmental and Archaeological Model-Based Age Estimate for the Colonization of Hawai’l

2014 ◽  
Vol 79 (1) ◽  
pp. 144-155 ◽  
Author(s):  
J. Stephen Athens ◽  
Timothy M. Rieth ◽  
Thomas S. Dye
Keyword(s):  
Bayesian Model ◽  
Depositional Model ◽  
Considerable Variability ◽  
Human Settlement ◽  
Posterior Density ◽  
Density Region ◽  
Radiocarbon Dates ◽  
The Core ◽  
Initial Settlement ◽  
Highest Posterior Density

AbstractRecent estimates of when Hawai’i was colonized by Polynesians display considerable variability, with dates ranging from about A.D. 800 to 1250. Using high resolution paleoenvironmental coring data and a carefully defined set of archaeological radiocarbon dates, a Bayesian model for initial settlement was constructed. The pollen and charcoal assemblages of the core record made it possible to identify and date the prehuman period and also the start of human settlement using a simple depositional model. The archaeological and paleoenvironmental estimates of the colonization date show a striking convergence, indicating that initial settlement occurred at A.D. 940–1130 at a 95 percent highest posterior density region (HPD), and most probably between A.D. 1000 to 1100, using a 67 percent HPD. This analysis highlights problems that may occur when paleoenvironmental core chronologies are based on bulk soil dates. Further research on the dating of the bones ofRattus exulans, a Polynesian introduction, may refine the dating model, as would archaeological investigations focused on potential early site locations.

Pre-LGM open-water conditions south of the Drygalski Ice Tongue, Ross Sea, Antarctica

2007 ◽  
Vol 19 (3) ◽  
pp. 373-377 ◽  
Author(s):  
Furio Finocchiaro ◽  
Carlo Baroni ◽  
Ester Colizza ◽  
Roberta Ivaldi
Keyword(s):  
Ross Sea ◽  
Open Water ◽  
Radiocarbon Dates ◽  
The Core ◽  
Bay Area ◽  
Terra Nova Bay ◽  
Insoluble Organic Matter ◽  
Victoria Land ◽  
Marine Isotope Stage 3 ◽  
Raised Beaches

AbstractA marine sediment core collected from the Nordenskjold Basin, to the south of the Drygalski Ice Tongue, provides new sedimentological and chronological data for reconstructing the Pleistocene glacial history and palaeoenvironmental evolution of Victoria Land. The core consists of an over consolidated biogenic mud covered with glacial diamicton; Holocene diatomaceous mud lies on top of the sequence. Radiocarbon dates of the acid insoluble organic matter indicate a pre-Last Glacial Maximum age (>24kyr) for the biogenic mud at the base of the sequence. From this we can presume that at least this portion of the western Ross Sea was deglaciated during Marine Isotope Stage 3 and enjoyed open marine conditions. Our results are consistent with recent findings of pre-Holocene raised beaches at Cape Ross and in the Terra Nova Bay area.

Geochemical aspects of the Santonian Chalk of Ramsgate, England, and the origin of the chert and clay minerals

1979 ◽  
Vol 43 (325) ◽  
pp. 159-164 ◽  
Author(s):  
D. A. Spears
Keyword(s):  
Clay Minerals ◽  
Upper Cretaceous ◽  
Major Element ◽  
Clay Content ◽  
Carbonate Content ◽  
Element Geochemistry ◽  
Carbonate Sedimentation ◽  
Volcanic Debris ◽  
The Mean

SummaryThe mineralogy and major-element geochemistry of thirty-seven samples from a borehole in the Upper Cretaceous Chalk (Santonian) of Kent has been determined. The mean carbonate content is 97% and the carbonate is a low-Mg calcite (0.42 mol % MgCO3). Most of the silica is deduced to be biogenic chert. The total clay content probably varies through the sequence due to changes in the rate of carbonate sedimentation. The clay composition remains relatively constant with smectite more abundant than illite. The smectite and K-feldspar could be formed from volcanic debris whereas illite and quartz are thought to be detrital.

scholarly journals Climatic signals in lacustrine deposits of the Upper Yacoraite Formation, Western Argentina: Evidence from clay minerals, analcime, dolomite and fibrous calcite

Sedimentology ◽  
2020 ◽  
Vol 67 (5) ◽  
pp. 2282-2309
Author(s):  
João Paulo B. Gomes ◽  
Rodrigo B. Bunevich ◽  
Sandra N. Tonietto ◽  
Daisy B. Alves ◽  
Julice F. Santos ◽  
...  
Keyword(s):  
Clay Minerals ◽  
Lacustrine Deposits ◽  
Climatic Signals

scholarly journals Operation of the Harwell UK 14C Data Base and its Expansion Through Data Exchange with Other Laboratories

Radiocarbon ◽  
1990 ◽  
Vol 32 (1) ◽  
pp. 31-36 ◽  
Author(s):  
A J Walker ◽  
R L Otlet ◽  
R A Housley ◽  
Johannes van der Plicht
Keyword(s):  
Data Base ◽  
Data Exchange ◽  
Data Bases ◽  
Computer Data ◽  
Radiocarbon Dates ◽  
Storage And Retrieval ◽  
The Core ◽  
The United Kingdom ◽  
Keyboard Typing ◽  
The Uk

The use of computer data bases for storage and retrieval of 14C data is a logical application for the rapidly expanding numbers of 14C determinations. Harwell has established a data base for all samples originating from sites in the United Kingdom and Eire. The core of the data is the Council for British Archaeology's published Index of Radiocarbon Dates which we are expanding to include all Harwell UK dates released for publication by the submitters plus dates from other laboratories both within and outside the UK. As a demonstration of the feasibility of direct database-to-database communication, cooperation has been sought from Groningen and Oxford to transfer computer files containing 14C results for UK sites. Neither of these laboratories use the same system as Harwell for their in-house data base and this exercise highlights the importance of a transfer language for both the national and international schemes as it is no longer practical to carry out such procedures through keyboard typing.

Sedimentology, Mineral Facies, and Petrofabric of the Meaford–Dundas Formation (Upper Ordovician) in Southern Ontario

1973 ◽  
Vol 10 (12) ◽  
pp. 1790-1804 ◽  
Author(s):  
K. Czurda ◽  
C. G. Winder ◽  
R. M. Quigley
Keyword(s):  
Clay Minerals ◽  
Heavy Minerals ◽  
Carbonate Content ◽  
The South ◽  
Upper Ordovician ◽  
Quartz Content ◽  
Southern Ontario ◽  
The North ◽  
Bedding Planes ◽  
Diffraction Patterns

The Meaford–Dundas Formation in southern Ontario is a medium gray shale with good fissility and resistant interbeds of gray fossiliferous limestones and siltstones. The hard layers are up to 20 cm in thickness and comprise 10 to 20% of the formation. The shale layers vary in thickness from 50 cm to 2 m.The clay minerals are principally illite, iron-chlorite, and small amounts of vermiculite and mixed-layer types. The carbonate content seems constant across the area at about 4 to 5% of the formation, except for the southwestern area where the carbonate increases to 20 or 25%. This increase is chiefly in dolomite content, a feature which reflects such factors as original conditions of deposition and possibly diagenesis subsequent to burial. The quartz content in the shale beds, and especially in the hard interbeds, increases towards the north to an average of 35 to 40% compared with 10 to 15% in the south. Framboids (aggregates of pyrite grains in spheroidal clusters) are a striking feature of the shale beds of the Meaford–Dundas Formation in the Meaford area.Fabric studies by means of X-ray diffraction patterns and scanning electron photomicrographs reveal, in most cases, high parallelism of clay platelets in the bedding planes, resulting in the good fissility of the shale.The principal source rock areas are the Appalachian orogen in the east (Taconic Mountains), which probably supplied most of the clay minerals and some quartz, and the Canadian Shield in the north, which provided the basin of sedimentation in the south with heavy minerals and additional quartz.

Geochemistry and time-series analyses of orbitally forced Upper Cretaceous marl–limestone rhythmites (Lehrte West Syncline, northern Germany)

2005 ◽  
Vol 142 (1) ◽  
pp. 31-55 ◽  
Author(s):  
BIRGIT NIEBUHR
Keyword(s):  
Clay Minerals ◽  
Low Frequency ◽  
Geochemical Data ◽  
Carbonate Content ◽  
Element Geochemistry ◽  
Low Magnesium ◽  
Magnesium Calcite ◽  
High Carbonate ◽  
Time Series Analyses ◽  
End Members

A cyclic marl–limestone succession of Middle–Late Campanian age has been investigated with respect to a Milankovitch-controlled origin of geochemical data. In general, the major element geochemistry of the marl–limestone rhythmites can be explained by a simple two-component mixing model with the end-members calcium carbonate and ‘average shale’-like material. Carbonate content varies from 55 to 90%. Non-carbonate components are clay minerals (illite, smectite) and biogenic silica from sponge spicules, as well as authigenically formed zeolites (strontian heulandite) and quartz. The redox potential suggests oxidizing conditions throughout the section. Trace element and stable isotopic data as well as SEM investigations show that the carbonate mud is mostly composed of low-magnesium calcitic tests of planktic coccolithophorids and calcareous dinoflagellate cysts (calcispheres). Diagenetic overprint results in a decrease of 2% δ18O and an increase in Mn of up to 250 ppm. However, the sediment seems to preserve most of its high Sr content compared to the primary low-magnesium calcite of co-occurring belemnite rostra. The periodicity of geochemical cycles is dominated by 413 ka and weak signals between 51 and 22.5 ka, attributable to orbital forcing. Accumulation rates within these cycles vary between 40 and 50 m/Ma. The resulting cyclic sedimentary sequence is the product of (a) changes in primary production of low-magnesium calcitic biogenic material in surface waters within the long eccentricity and the precession, demonstrated by the CaCO3 content and the Mg/Al, Mn/Al and Sr/Al ratios, and (b) fluctuations in climate and continental weathering, which changed the quality of supplied clay minerals (the illite/smectite ratio), demonstrated by the K/Al ratio. High carbonate productivity correlates with smectite-favouring weathering (semi-arid conditions, conspicuously dry and moist seasonal changes in warmer climates). Ti as the proxy indicator for the detrital terrigenous influx, as well as Rb, Si, Zr and Na, shows only low frequency signals, indicating nearly constant rates of supply throughout the more or less pure pelagic carbonate deposition of the long-lasting third-order Middle–Upper Campanian sedimentary cycle.

Climate change and human disturbance of fynbos vegetation during the late Holocene at Princess Vlei, Western Cape, South Africa

The Holocene ◽  
2011 ◽  
Vol 21 (7) ◽  
pp. 1137-1149 ◽  
Author(s):  
F.H. Neumann ◽  
L. Scott ◽  
M.K. Bamford
Keyword(s):  
Anthropogenic Disturbance ◽  
Late Holocene ◽  
Climate Changes ◽  
Western Cape ◽  
Radiocarbon Dates ◽  
The Core ◽  
Pollen Types ◽  
Hydrological System ◽  
Vegetation And Climate ◽  
Floating Mat

Pollen analysis of a core in Princess Vlei in the Fynbos Biome near Cape Town gives a 4150 year record of vegetation and climate changes followed by disturbance by colonial settlers since c. 300 years ago. Their impact replaced climate as a major factor in changing the vegetation. The chronology is based on eight radiocarbon dates. Pollen types such as Restionaceae, Ericaceae, and Proteaceae reflect changes in fynbos. Pollen indicators at the bottom of the core suggest drier conditions followed by an increase in Morella, Cyperaceae and Carpacoce pollen, which might indicate moist conditions c. 3400–2600 cal. yr BP. Drier conditions prevail c. 2600–1900 cal. yr BP. Apparent light disturbance after c. 2000 cal. yr BP might be attributed to Khoi herders. Deeper water and damp surroundings are indicated c. 1900–1000 cal. yr BP. The top of the core shows an increase of Poaceae while Restionaceae decrease with anthropogenic disturbance, including the introduction of neophytes such as Pinus ( c. 300 years ago) and Zea mays. Charcoal percentages point to intense fires after the arrival of the Europeans. Water between 105 and 75 cm indicates the development of a floating mat resulting from changes in the hydrological system possibly connected to disturbances by settlers.

Mobility of Uranium, Thorium and Lanthanides Around the Bangombe Natural Reactor (Gabon)

1994 ◽  
Vol 353 ◽  
Author(s):  
R. Bros ◽  
F. Gauthier-Lafaye ◽  
P. Larque ◽  
J. Samuel ◽  
P. Stille
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Clay Minerals ◽  
Nuclear Reactor ◽  
Black Shales ◽  
Weathering Profile ◽  
The Core ◽  
Reducing Conditions ◽  
Isotopic Studies ◽  
Textural Evidence

AbstractNew mineralogical and isotopic studies were carried out on samples from the Bangombé natural nuclear reactor. This reactor is located at shallow depth in the weathering profile and has been subjected to severe supergene alteration. Textural evidence indicates partial dissolution of uraninite in the Bangombé ore related to precipitation of Fe-Ti oxi-hydroxides and clay minerals (kaolinite and metahalloysite). As a consequence of the alteration of the uraninite, uranium and f issiogenic rare earth elements were released in the clayey border of the reactor, whereas radiogenic 232Th remained confined in the close vicinity of the core. A retention effect is also evidenced, under reducing conditions, in the black shales located above the reactor.

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