Speleology in Kosgala Wawul Guhawa Cave at Ihalawatta in Rathnapura Distric, Sri Lanka

Speleology in Kosgala Wawul Guhawa Cave at Ihalawatta in Rathnapura Distric, Sri Lanka

Weliange W.S¹, Pathmakumara Jayasinghe², Dandeniya A.S³, Prageeth Elgiriya¹, Dinesh D. Dewage⁴, Duminda Aalahakoon A.M⁵ & Nilupul Hettiarchchi⁶

¹Postgraduate Institute of Archaeology, 407, Bauddhaloka Mawatha, Colombo 7, Sri Lanka.

²Research Laboratory, Central Cultural Fund, No 11, Colombo 07, Sri Lanka

³BGJF Consultancy Services, 35A ½, Sunethradewi Road Kohuwala, Nugegoda, Sri Lanka.

⁴Department of Archaeology, University of Kelaniya, Sri Lanka.

⁵132, Track 5, Rajanganaya, Sri Lanka.

⁶658/52, NewTown , Rathnapura, Sri Lanka

Corresponding author; wasanthaweliange@yahoo.co.uk

Abstract

A vast dark space beneath a huge gneissic rock roof is the definition for the Kosgala Wavul Guhawa Cave and it is an underground tunnel cave. This cave was located in (06°43' 31.5'' N, 80°20' 34.6'' E) Ihalawatta in Rathnapura district, 486 ft above msl. This particular cave was studied in November 2009 under the Speleology project carried out by the Post Graduate Institute of Archaeology of the University of Kelaniya. In order to get the spatial distribution of the cave, mapping was done and cave mouth, plan and sections were drawn. Special geological features, speleotherms and cave fauna were studied and photographed. As a result of weathering of bed rock and consequent erosion, Cave has been formed. Carving features due to abrasion of water disclose further support in formation of the cave. A pot hole in southeast chamber evidences action of water on bed rock erosion. Morphological studies reveal that the cave space is spread over an area of 110 m to 90 m and it is divided into two chambers as the northeast chamber and northwest chambers. Northeast chamber is characterized by flat ground surface, high roof and a space of 75 m long and 25 m wide at the widest point. 100 m long northwest chamber has a steep slope (45⁰) of ground and a lower roof. Cave mouth is oriented towards the south. Ground of the cave is composed of geometrical shaped boulders (3-5 m in size), pebbles, coarse sand derived mainly from physical weathering, bat guano and organic material in the form black soil. The cave is a home for large number of michrochiropterna bats, cockroaches, cave crickets and spiders. Abundant speleotherms is a characteristic feature and stalagmites found in the northeast chamber seem to be still young. Black colored flowstone also was found in several places of the cave. Further exploration would definitely reveals more interesting facts about this cave.

Keywords; bat guano, cave fauna, gneissic roof, michrochiroptera, pot hole, speleothems

Introduction

Sri Lanka is an island with a very high density of caves since the lithology is characterized by mostly Precambrian metamorphic rocks and Miocene limestone in the northern area of the country (Cooray 1994). Caves found in different lithologies in Sri Lanka are of historical, cultural and archaeological significance. Only few caves have been studied in archaeological aspects during the last 50 years in Sri Lanka although people visit caves for other reasons such as religious purposes, collecting guano, having fun and adventure and treasure hunting. Scientific study of a cave with a multidisciplinary approach is known as Speleology.

Open cavities on earth are known as Caves which are wonderful geological formations. Caves are diverse in morphology and genesis and formation of a cave is matter of time, rate of weathering and erosion, climate and type of bed rock (Bosak, 2008; Parmer, 2003; Piccini, 1995; Hill, 2000). Caves have long been interest of archaeologist since they are paleo occupations for prehistoric people (Jankovic et al, 2006; Karkanas et al, 2000) and they preserve extraordinary records of past humans, their evolution and paleo-environmental changes (Goldberg and Nathan, 1975; Spotl and Mangini, 2007; Springer et al, 1997; Yong et al, 2007). Caves are places of mineral resources and people have harvested those resources since long time (Kennedy and Watson, 1997). Recently cave tourism is becoming a popular adventure in the world (Lobo and Moretti, 2009).

adventure in the world (Lobo and Moretti, 2009).

Based on rock formations/lithologies different kinds of caves have been originated (Hill, 2000; Karmen et al, 2001). Most famous caves in the world are Karstic or Limestone caves due to the fact those karstic caves are wonderfully decorated with speleotherms (Baskar et al, 2007) and most of studies have been carried out on those Karstic caves. In addition Sandstone caves were also recorded (Waltham and Chubby, 1997). It seems that genesis of such sedimentary caves is common and known as paragenesis and dissolution (Pasini, 2009). Dissolved materials of the limestone bed rock are precipitated somewhere else to form spleotherms such as Stalgmites and Stalactites which are the natural sculptures of caves (Woo et al, 2005).

Although cave exploration is being done since a long time by adventurous youths proper scientific explorations were started recently. Deraniyagala (1965) has published one publication about cave exploration and the importance of Speleological research. During the last 70 years only very few publications have being done about scientific cave studies among them many are dedicated for cave fauna (Bringoli 1972; Silhavy, 1974; Mauries, 1981; Jayasingha et al, 2009b; Weliange, 2009; Weliange & Namalagamuwa, 2009).