Unusual Isolated Large Clasts from the Periphery of the Lagonaki Highland, Western Caucasus: New Evidence of Classification and Origin

Abstract

Large clasts are in focus of the modern geoscience research, but their broadly-accepted classification is absent and specialists tend to over-emphasize on clasts of coastal zones. New field investigations in the Western Caucasus have permitted the finding of isolated large clasts of carbonate composition that occur above the Early-Middle Jurassic shale sequence and that are covered by modern soils. These clasts can be determined either as large boulders or megaclasts (blocks) depending on the preferred classification. Their shape is chiefly irregular, although smoothened surfaces and rounded angles (resulting from previous karstification) are also registered. These large clasts are located quite far from the natural outcrops of the Late Jurassic carbonates, which are their parent rocks. The origin of these clasts can be linked to collapses of the Pleistocene cliff of a cuesta-type mountain range, which later retreated to its present position. The evidence from the study area implies the size of 1 m or 2 m as a plausible criterion for distinction of boulders and megaclasts, and it also makes claims towards the development of a wider genetic typology of megaclasts.

Aesthetic Value of Colluvial Blocks in Geosite-Based Tourist Destinations: Evidence from SW Russia

“…Big stones occur there either individually or in groups on mountain slopes covered by dense forest. These sedimentary clasts are very typical for the entire mountainous part of Adygeya [12] and result from slope collapse and cliff retreat, i.e., these clasts are colluvial in origin [13]. The objective of the present paper is to provide the first report of the aesthetic properties of colluvial blocks occurring in the Partisan Glade tourist destination.…”

“…The Partisan Glade tourist destination (44 • 05'N, 40 • 10'E) is located to the west of the small town of Guzeripl in the Western Caucasus (Figure 1). The landscape is dominated by mountain ranges ( Figure 2) and valleys of small rivers and streams; the elevation ranges between 600 m and 2000 m. The ranges are either symmetrical, with more or less smoothed slopes (e.g., the Inzhenernyy Range and the Skazhennyy Range), or they are asymmetrical, cuesta-type ranges, with one very gentle slope and the other a steep, cliffed slope (e.g., the Kamennoe More Range) [13]. The main rivers are the Zhelobnaya River and its right tributary, namely the Armyanka River.…”

“…Geologically, this tourist destination is fully dominated by the folded and faulted Lower-Middle Jurassic black shales with rare and thin sandstone and siltstone interbeds [13][14][15]. Their lengthy outcrops stretch for many kilometers along the road.…”

“…Their lengthy outcrops stretch for many kilometers along the road. The Upper Jurassic reefal limestones and dolostones are exposed in the uppermost parts of the slopes [13][14][15]. These rocks were formed in a back-arc basin that persisted from the mid-Mesozoic to the mid-Cenozoic [16], and the modern mountains are the direct outcome of the Late Cenozoic (Alpine) orogeny [17][18][19] that have resulted from a plate collision [20].…”

“…The objective of the present paper is to provide the first report of the aesthetic properties of colluvial blocks occurring in the Partisan Glade tourist destination. It is based on new field investigations and does not repeat the previous findings [12,13]. Aesthetic properties of the studiedbig stones are 'projected' on the local scenic beauty.…”