ISSUE 10, 2011

  PDF: /pdf/seka_pdf9531.pdf

Abstract:

Three dye tracing have been carried out in the Nakanai Mountains to determine Berenice spring catchment area and some internal connections inside Muruk Cave. Andromede Cave belongs to Muruk-Berenice system, via Arcturus main drain. Due to special conditions in rainforest with difficult of moving, we made qualitative tracing using charcoal bags.

  PDF: /pdf/seka_pdf9530.pdf

Abstract: Rainfall and runoff data do not exist in Nakanai Mountains, the main range of New Britain Island, Papua New Guinea. We collected field data during a 4 weeks expedition in the rainforest. In the mountain, the annual rainfall may be about 12 m; the soil is able to absorb a 50 mm rainfall, but a 20 mm shower starts runoff if the soil is saturated by a previous rain and gullies sinking in caves are flooded. Flooding propagates at about 1 km/h inside Muruk Cave. The discharge of the main rivers, Matali and Galowe, correspond respectively in low water to 27 and 33 m3 /s. The ratios between low, medium, flood and exceptional flows are respectively 1, 5, 10 and 50.

  PDF: /pdf/seka_pdf9529.pdf

Abstract: The Alecrineiros Shaft is a cave developed in the St. Antonio Plateau, Portugal. This cave develops on a gently dipping monocline structure, along two major fracture families. These discontinuities are sub-vertical and exhibit the following directions: E-W to N70W and N-S to N30E. The shaft presents evidences of several speleogenetic processes compatible with a genesis and development in a vadose regime at the base of the epikarstic zone.

  PDF: /pdf/seka_pdf9528.pdf

Abstract: Muruk is the deepest cave in the Southern Hemisphere (1178 m of depth). It gives an access to go through the Nakanai Mountains and across large galleries, sometimes more than 50 m wide. Considering the important rainfall, the very active uplifting and the presence of a rainforest, Papua can be regarded as a hyperkarst, with large morphological forms evolving very quickly. U/Th and paleomagnetic dating on cave sediments confirm this point of view, assigning a very recent age to this cave system (100 to 200 kyr). Muruk is a model of juvenile systems with a regularly inclined profile and with a monophase evolution excluding any old perched level, unlike usual cave systems. These characteristics are essential for understanding notonly the first speleogenetic phases, but also the more evolved systems found throughout the world

  PDF: /pdf/seka_pdf9525.pdf

Abstract: Blomstrandsøya, at Kongsfjord (780 57’N), Spitsbergen, is within the high arctic, a completely permafrozen zone. The bedrock consists of Paleozoic marbles and has yielded a surprising amount of karst features. Early phases of hydrothermal, possibly Caledonian, speleogenesis and subsequent Devonian karstification with redbed deposits is well documented. 62 active seacaves, and more than 30 relict karst caves were found in the coastal cliffs and in escarpment faces around the island. All caves have very limited extent; they are either quite short, like most of the active sea caves, or they are soon choked by frozen sediments and ground ice after a few meters. The deepest penetration was some 34 m into the surface cliff. Many of the relict caves are scalloped and display well-defined paragenetic wall and ceiling half-tubes, implying that they are indeed conduits, leading further into the rock mass, beyond their present permafrozen terminations. Most of the speleogenetic volume of the relict caves is ascribed to sub-glacial conditions during stadials, when the site was covered beneath thick ice sheets. In many cases, the present caves were formed by reactivation of pre-existing paleokarst voids. Due to the present intense gelifraction and erosion in the littoral zone, and the relatively constant sea level during the past 9.5 kyr, most of the volume of the sea caves can be explained by processes acting during the Holocene.
Keywords: karst; speleogenesis; arctic; permafrost; Quaternary; subglacial