Climatic signals in clay mineralogy and grain-size variations in Owens Lake core OL-92, southeast California

1997 ◽  
Author(s):  
Kirsten M. Menking
Keyword(s):  
Grain Size ◽  
Clay Mineralogy ◽  
Owens Lake ◽  
Climatic Signals ◽  
Lake Core

scholarly journals Grain size distribution, clay mineralogy and chemistry of bottom sediments from the outer Thermaikos Gulf, Aegean Sea, Greece

2004 ◽  
Vol 5 (1) ◽  
pp. 43
Author(s):  
K.G. PEHLIVANOGLOU ◽  
G. TRONTSIOS ◽  
A. TSIRAMBIDES
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Clay Minerals ◽  
Grain Size Distribution ◽  
Bottom Sediments ◽  
Clay Mineralogy ◽  
Aegean Sea ◽  
Wide Range ◽  
Differential Settling ◽  
Interstratified Phase

The Thermaikos Gulf constitutes the NW part of the North Aegean Sea and is limited eastward from the Chalkidiki Peninsula and westward from the Pieria Prefecture. Its plateau covers an area of 3,500 km2. The mechanisms responsible for the grain size distribution into the Gulf, the clay mineralogy and the chemistry of some bottom sediments from the outer Thermaikos Gulf, are examined. Source mixing during transportation, flocculation, differential settling processes and organic matter appear to be the main mechanisms for the distribution of clay minerals in shallow waters. All grain size fractions studied present a wide range of values confirming the extreme variations of the discharged load and the variability in marine processes. Plagioclases predominate over K-feldspars, while quartz is the most abundant mineral present. In addition, micas, chlorites, amphiboles and pyroxenes exist as primary and/or accessory minerals in all samples. Among clay minerals, illite predominates over smectite and smectite over chlorite (+ kaolinite). The ordered interstratified phase of I/S, with 30-35% S layers, is present in the 2-0.25µm fraction. The randomly interstratified phase of I/S, with 50% S layers, is present in the <0.25& micro; m fraction. On average the clay mineral content of the studied samples is: 48% I, 23% S, 17% Ch (+K) and 12% others for the 2-0.25µm fraction and 50% I, 30% S and 20% Ch (+K) for the <0.25 µm fraction. All these minerals are the weathering products of the rocks from the drainage basins of the rivers flowing into the Gulf, as well as of the Neogene and Quaternary unconsolidated sediments of the surrounding coasts. The terrigenous input, the water mass circulation and, to a lesser extent, the quality of the discharged material and the differential settling of grains, control the grain size distribution within the outer Thermaikos Gulf. The chemical composition of the analysed samples is generally in agreement with their mineral composition and signifies their terrigenous origin presenting discretely clastic character.

Sediment (grain size and clay mineralogy) and organic matter quality control on living benthic foraminifera

2009 ◽  
Vol 52 (1) ◽  
pp. 75-84 ◽  
Author(s):  
Éric Armynot du Châtelet ◽  
Viviane Bout-Roumazeilles ◽  
Armelle Riboulleau ◽  
Alain Trentesaux
Keyword(s):  
Grain Size ◽  
Quality Control ◽  
Organic Matter ◽  
Benthic Foraminifera ◽  
Clay Mineralogy ◽  
Sediment Grain Size ◽  
Organic Matter Quality

A mineralogical and geochemical study of turbidite sandstones and interbedded shales, Mam Tor, Derbyshire, UK

Clay Minerals ◽  
1981 ◽  
Vol 16 (4) ◽  
pp. 333-345 ◽  
Author(s):  
D.A. Spears ◽  
M.A. Amin
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Clay Mineral ◽  
Mixed Layer ◽  
Clay Mineralogy ◽  
Lateral Variation ◽  
Size Fractions ◽  
Shore Line ◽  
Geochemical Study ◽  
Size Sorting

AbstractEleven shales and fourteen turbidite sandstones from the Mam Tor Beds were analysed chemically and by XRD. The ratio of kaolinite to illite plus mixed-layer clay was higher in the sandstones than in the shales, size fractions demonstrating that this ratio decreased as the grain size decreased. Shales more basinal in character than those of the Mam Tor Beds contain more illite and mixed-layer clay and less kaolinite and it is suggested that there was a lateral variation in clay mineralogy with distance from the shore line due to particle size sorting and that the character of the clay mineral fraction was retained as the turbidity current transported sediment from a nearshore environment deeper into the basin. Support for this model was obtained from the geochemistry which showed that the sandstone matrix differed compositionally from the shales. Systematic variations occurred in the turbidite sandstones but not in the shales which are therefore considered to be non-turbiditic. Only minor mineralogical changes appear to have occurred during diagenesis.

230Th-excess inventory and distribution in a southern Mendeleev Ridge core (Arctic Ocean): linkage with late Quaternary sedimentological and paleogeographical changes

2020 ◽  
Author(s):  
Tengfei Song ◽  
Claude Hillaire-Marcel ◽  
Yanguang Liu
Keyword(s):  
Grain Size ◽  
Sea Ice ◽  
Arctic Ocean ◽  
Late Quaternary ◽  
Critical Time ◽  
Clay Mineralogy ◽  
Sedimentation Rates ◽  
Central Arctic Ocean ◽  
Sea Levels ◽  
Ice Production

&lt;p&gt;In addition to &lt;sup&gt;14&lt;/sup&gt;C-data, sedimentary excesses in &lt;sup&gt;230&lt;/sup&gt;Th &amp;#160;(&lt;sup&gt;230&lt;/sup&gt;Th&lt;sub&gt;xs&lt;/sub&gt;) in central Arctic Ocean cored sequences yielded critical time constrains and sedimentation rates estimates, at least, at sites characterized by very low sedimentation rates (&lt;&lt; 1cm/ka). Closer to the Russian margin, where higher accumulation rates are recorded based on &lt;sup&gt;14&lt;/sup&gt;C-ages, the setting of a reliable stratigraphy based on &lt;sup&gt;230&lt;/sup&gt;Th&lt;sub&gt;xs&lt;/sub&gt; reveals more challenging, as illustrated here, based on the analysis of &amp;#160;a gravity core raised from the southern Mendeleev Ridge (core ARC7-E25; -179.4&amp;#176;E, 79.0&amp;#176;N; 1200 m water depth; 320 cm long). Subsamples were collected at a 4 to 8 cm interval. Measurements included: AMS &lt;sup&gt;14&lt;/sup&gt;C in foraminifera, grain size, bulk Xray mineralogy, clay mineralogy, geochemistry (C&lt;sub&gt;org&lt;/sub&gt;, C&lt;sub&gt;inorg&lt;/sub&gt;,&lt;sup&gt;13&lt;/sup&gt;C&lt;sub&gt;org&lt;/sub&gt;, &lt;sup&gt;238&lt;/sup&gt;U, &lt;sup&gt;234&lt;/sup&gt;U, &lt;sup&gt;230&lt;/sup&gt;Th, &lt;sup&gt;226&lt;/sup&gt;Ra, &lt;sup&gt;210&lt;/sup&gt;Pb). Data indicate that some sediment were lost at core top. Nevertheless, &lt;sup&gt;14&lt;/sup&gt;C and &lt;sup&gt;230&lt;/sup&gt;Th&lt;sub&gt;xs &amp;#160;&lt;/sub&gt;data allow estimating a mean sedimentation rate of about 6 to 7 mm/ka during the last two climatic cycles. A comparison of the &lt;sup&gt;230&lt;/sup&gt;Th&lt;sub&gt;xs &lt;/sub&gt;inventory and distribution pattern with those from other cores allows identifying important parameters involved in the cycling of the water column-produced &lt;sup&gt;230&lt;/sup&gt;Th in this basin and its sporadic sedimentary accumulation, in particular linkages with sea-ice production over shelves, thus sea-levels, sea-ice rafting routes, grain-size and mineralogy, potential winnowing of fine fractions, role of brines and relative duration of intervals with reduced or nil sedimentation preceding &lt;sup&gt;230&lt;/sup&gt;Th&lt;sub&gt;xs&lt;/sub&gt;-accumulation intervals.&lt;/p&gt;

scholarly journals A continuous 4000-year lake-level record of Owens Lake, south-central Sierra Nevada, California, USA

2018 ◽  
Vol 90 (2) ◽  
pp. 276-302 ◽  
Author(s):  
Steven N. Bacon ◽  
Nicholas Lancaster ◽  
Scott Stine ◽  
Edward J. Rhodes ◽  
Grace A. McCarley Holder
Keyword(s):  
Water Level ◽  
Sierra Nevada ◽  
Lake Level ◽  
Water Levels ◽  
Mono Lake ◽  
Ice Age ◽  
Integrated Analysis ◽  
Owens Lake ◽  
South Central ◽  
Lake Core

AbstractReconstruction of lake-level fluctuations from landform and outcrop evidence typically involves characterizing periods with relative high stands. We developed a new approach to provide water-level estimates in the absence of shoreline evidence for Owens Lake in eastern California by integrating landform, outcrop, and existing lake-core data with wind-wave and sediment entrainment modeling of lake-core sedimentology. We also refined the late Holocene lake-level history of Owens Lake by dating four previously undated shoreline features above the water level (1096.4 m) in AD 1872. The new ages coincide with wetter and cooler climate during the Neopluvial (~3.6 ka), Medieval Pluvial (~0.8 ka), and Little Ice Age (~0.35 ka). Dates from stumps below 1096 m also indicate two periods of low stands at ~0.89 and 0.67 ka during the Medieval Climatic Anomaly. The timing of modeled water levels associated with 22 mud and sand units in lake cores agree well with shoreline records of Owens Lake and nearby Mono Lake, as well as with proxy evidence for relatively wet and dry periods from tree-ring and glacial records within the watershed. Our integrated analysis provides a continuous 4000-yr lake-level record showing the timing, duration, and magnitude of hydroclimate variability along the south-central Sierra Nevada.

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