title: Holocene fluctuations of a meromictic Lake in southern British Columbia

authors: Lowe, David J.

abstract: Holocene deposits of Mahoney Lake, a meromictic saline lake located in a closed basin in the semi-arid Okanagan Valley, contain evidence of frequent and marked changes in lake depth (up to >12 m/100¹⁴C yr) probably caused by short-term changes in effective precipitation. We studied a 5.45-m-long core comprising a basal layer of inorganic mud overlain by a succession of layers of calcareous laminated and nonlaminated organic mud, marl, and sand. We used Mazama tephra to adjust nine radiocarbon ages for the hardwater effect. Meromixis developed ca. 9000¹⁴C yr B.P., and the lake has been episodically meromictic for about half the time since. Because of close linkages between sediments and depositional environments in meromictic and saline lakes, we infer that laminated sediments indicate meromictic conditions and high lake levels (>ca. 12 m water depth), whereas thick marl layers and nonlaminated sediments indicate nonmeromictic conditions and thus low lake levels (<ca. 8 m depth). Many of the inferred short-term climatic changes have not been identified in previous studies in northwestern North America, perhaps because of insensitive climatic proxies, inadequate temporal resolution, or discounting of anomalous findings.

text: Holocene fluctuations of a meromictic Lake in southern British Columbia Holocene deposits of Mahoney Lake, a meromictic saline lake located in a closed basin in the semi-arid Okanagan Valley, contain evidence of frequent and marked changes in lake depth (up to >12 m/100¹⁴C yr) probably caused by short-term changes in effective precipitation. We studied a 5.45-m-long core comprising a basal layer of inorganic mud overlain by a succession of layers of calcareous laminated and nonlaminated organic mud, marl, and sand. We used Mazama tephra to adjust nine radiocarbon ages for the hardwater effect. Meromixis developed ca. 9000¹⁴C yr B.P., and the lake has been episodically meromictic for about half the time since. Because of close linkages between sediments and depositional environments in meromictic and saline lakes, we infer that laminated sediments indicate meromictic conditions and high lake levels (>ca. 12 m water depth), whereas thick marl layers and nonlaminated sediments indicate nonmeromictic conditions and thus low lake levels (<ca. 8 m depth). Many of the inferred short-term climatic changes have not been identified in previous studies in northwestern North America, perhaps because of insensitive climatic proxies, inadequate temporal resolution, or discounting of anomalous findings.

year: 1997

title: The geochemistry of soluble salts in the Wright and Taylor Valleys, South Victoria Land, Antarctica

authors: Field, Adrian Bruce

subjects: salt

abstract: Samples of salt deposits, snow, meltwater and soils were collected in the Wright and Taylor Valleys, South Victoria Land, during the summer field season of 1973-74. The primary aim of the work carried out was to demonstrate the application of chemical techniques to geological problems in the Dry Valleys of Antarctica.
Salt samples identified by X-ray diffraction patterns were halite, thenardite and mirabilite. Snow, ice and groundwater samples were analysed for Na⁺, Ca²⁺, Mg²⁺, K⁺. Cl⁻ and SO₄²⁻. The results show that atmospheric transport from the sea is probably the most important source of supply of salts to the Dry Valley system, with saline groundwater flows as important means of transport of salts to the Dry Valley lakes.

text: The geochemistry of soluble salts in the Wright and Taylor Valleys, South Victoria Land, Antarctica Samples of salt deposits, snow, meltwater and soils were collected in the Wright and Taylor Valleys, South Victoria Land, during the summer field season of 1973-74. The primary aim of the work carried out was to demonstrate the application of chemical techniques to geological problems in the Dry Valleys of Antarctica.
Salt samples identified by X-ray diffraction patterns were halite, thenardite and mirabilite. Snow, ice and groundwater samples were analysed for Na⁺, Ca²⁺, Mg²⁺, K⁺. Cl⁻ and SO₄²⁻. The results show that atmospheric transport from the sea is probably the most important source of supply of salts to the Dry Valley system, with saline groundwater flows as important means of transport of salts to the Dry Valley lakes.

year: 1975

title: Verbs in Māori: The problem of definitional criteria

authors: Whaanga, Hēmi

subjects: te reo Māori

abstract: A range of different types of criteria has been applied at different points in the history of the classification of verbs in Māori. These have included syntactic and morphological criteria, semantic criteria and derivational criteria. Unfortunately, these criteria have not always been applied consistently and this has led to considerable disagreement about the classification of verbs in Māori. In this paper, different accounts of verb classification in Māori are critically examined and it is argued that some of the disagreements can be resolved by acknowledging (a) that words in Māori may be assigned to different word classes in different contexts, and (b) that word classes and sub-classes should be determined on the basis of morphological and syntactic criteria with semantic and derivational information playing a role only in so far as they have observable syntactic and/or morphological consequences.

text: Verbs in Māori: The problem of definitional criteria A range of different types of criteria has been applied at different points in the history of the classification of verbs in Māori. These have included syntactic and morphological criteria, semantic criteria and derivational criteria. Unfortunately, these criteria have not always been applied consistently and this has led to considerable disagreement about the classification of verbs in Māori. In this paper, different accounts of verb classification in Māori are critically examined and it is argued that some of the disagreements can be resolved by acknowledging (a) that words in Māori may be assigned to different word classes in different contexts, and (b) that word classes and sub-classes should be determined on the basis of morphological and syntactic criteria with semantic and derivational information playing a role only in so far as they have observable syntactic and/or morphological consequences.

year: 2000-10