摘要:

Some recent studies of raised shorelines in western Scotland, which are gaining international acceptance, are assessed in the light of subsequent criticisms. Fieldwork has revealed that there are differences in altitude measurements, interpretations, and conclusions between these studies and the present one in Lorn and eastern Mull. Two short lateglacial shorelines are tentatively suggested, but there is a general abesence of clear, widespread shorelines of this age. The Main Postglacial Shoreline has a gradient of 0.05 m/km, considerably less than found in previous studies in both western and south‐cast Scotland. Subsequently, as relative sea level fell to its present level, two fairly clear shorelines with low gradients were formed together with traces of intermediate ones. The influences of the. Falls of Lora rock bar and of exposure on showline altitude are also examine

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1974.tb00671.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

The formulas for correcting14C measurements are explained. The expected ranges of the δ13C values for some types of samples are given. It is pointed out that the corrections are approximate because of the choice of correction formula, and that all samples arc normalized to wood samples instead of to carbon dioxide of the air. Some results from the Uppsala laboratory for plant materials and carbonates are given

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1974.tb00672.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

The name Mérida Glaciation is proposed to designate the alpine glaciation which affected the central Veneruelan Andes; during the Late Pleistrocenc. Two main morainie levels have been recognired: one between 2600 and 2700 m, and another between 3000 and 3500 m elevation. The snow line during the last glacial advance was lowered approximately 1200 m below the present snow line (3700 m). Rodiocarbon dating indicates that the moraines are older than 10,000 years B.P., and probahly older than 13,000 years B.P. The lower morainie level probably corresponds to the main Wisconsin glacial advance. The upper level probably represents the last glacial advance (Late Wisconsin)

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1974.tb00673.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Subsurface large‐scale patterned ground structures, observed as crop‐marks in cereal fields with spring‐barley and oats have been detected in southwestern Jutland. It is assumed that the structures revealed are fossil ice‐wedge polygons. Mode of origin, time of formation and palneoclimatic significance of ice‐wedge casts are discussed. Texture of poorly layered wedge‐fill materials can be distinguished from that of the stratified materials transected by the wedges, causing stress conditions in crop, in dry summers, seen as differential growth and cereal ripening. The water‐holding capacity is highest in wedge‐fill materials. Plants growing above the ice‐wedge casts arc able to withstand a certain deficiency in precipitation during spring and early summer. Cereals growing outside ice‐wedge casts suffer owing to lack of available moisture, and growth may be restricted, even to the extent that the plants can wither. Consequently, crop‐marks of variable growth appear in the fields. A growth season with high precipitation makes it difficul

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1974.tb00674.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY