Zemes un vides zinātnes Earth and Environment Sciences - Latvijas ...
Zemes un vides zinātnes Earth and Environment Sciences - Latvijas ...
Zemes un vides zinātnes Earth and Environment Sciences - Latvijas ...
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O.A. Lebedev. A new tetrapod from Russia<br />
81<br />
Fig. 1. Map showing location of the Gornostayevka quarry, marked by an asterisk. Location of<br />
previously known tetrapod site Andreyevka-2 marked by a black diamond.<br />
currents to burial in different environments. The fossiliferous lens <strong>and</strong> pocket are overlain<br />
with a thin layer of plastic reddish-brown clay <strong>and</strong> fine-grained quartz, white <strong>and</strong> brownish<br />
s<strong>and</strong>s containing rare <strong>and</strong> poorly preserved vertebrate fragments. Moloshnikov (2001)<br />
suggested that the site was formed as a result of temporary stream activity within the<br />
shallow-water near-shore zone of an epicontinental basin.<br />
Most of the bones are to some extent eroded, however some of them are intact,<br />
implying different conditions of transport. Bone colour varies from white to brown <strong>and</strong><br />
black depending on the rate of their impregnation with iron <strong>and</strong> manganese oxides <strong>and</strong><br />
salts. The hardness of the bone is also influenced by mineral impregnation, making<br />
white <strong>and</strong> yellowish bone very fragile <strong>and</strong> dark-brown <strong>and</strong> black ones extremely solid.<br />
The amo<strong>un</strong>t of iron <strong>and</strong> manganese oxides <strong>and</strong> salts may suggest former proximity to<br />
denudation areas (Tolstikhina 1952). Thus, it is not clear how much of the bone was<br />
brought from upl<strong>and</strong>s by streams <strong>and</strong> how much was deposited in situ.