Projektteil 05: Report Excavation Grubalacke 2008



A.o. Univ.-Prof. Dr. Walter Leitner


Thomas Bachnetzer Bakk. phil. 
Mag. phil. Beatrix Nutz
Julia Hammerschmied Bakk. phil. 

University of Innsbruck
Institute of Archaeologies
Center for Ancient Cultures
Langer Weg 11
A-6020 Innsbruck

Grabung 2008 


The excavation took place from 3rd to 18th of July under the superintendence of Univ. Prof. Dr. Walter Leitner. Within the project HiMAT -  History of Mining Activities in the Tyrol  - it is aim of the research to explore the Rofan Mountains as a resource region for flint stone. Since a couple of years the region is known due to surface finds of flint tools  to have been hunting ground and pasture for stone age hunters-gatherers and herdsmen from the 7th to 6th millennium B.C. The traces left point on camps being regularly visited during the summer hunting season where production of stone tools took place. The raw material used for these tools comes in large parts from the surrounding area. Several flint stone varieties (radiolarian rock, chert varieties), to some extent of considerable quality, can be found. Doubtless one reason to frequent the Rofan region during the Stone Age was to obtain this useful stone material, whose hardness and elasticity makes it easily worked into sharp-edged implements. In this context we also know the Rofan Mountains of having been – several millennia later – of economic interest when gunflints for flintlock firearms were manufactured and exported in the 16th century (c.f. Tiroler Landreim by Georg Rösch von Geroldshausen in 1557/58). Two areas within the range of the Grubastieg (lot number 188) and the Grubalacke (lot number 186) were chosen for the excavation campaign of 2008.

Reason for the survey in a shallow depression at an open mountain pasture near the Grubastieg was given by charcoal finds who’s C14-dates brought about a result of ca. 2.700 B.C. Unfortunately no further evidence for a Stone Age site could be provided.

So the work focused predominantly on the western shore area at the Grubalacke where Stone Age tools have already been detected on several occasions and red radiolarian rock is found in-situ. In the immediate vicinity of the western lakeside three rectangular areas of 8 sqm each were dug off. In the process weathered radiolarian rock layers on top of the jointed lime formation were located. However this raw material is of little or no use for tool production. On the other hand best quality flint in nodules is found ready to be picked up or easily be quarried out of weathered layers directly beneath the top soil. Thus regular mining was not necessary. This also applies to the chert varieties found in the surrounding area who´s nodules often form large stockpiles. The best nodules were collected, battered and the best pieces then used for the production of flint blades. In the process innumerable stone chips and bad quality cores added to the waste.   Between the brick-red layers exposed in the excavation sections at the Grubalacke a grey colouration could be observed wherein exceedingly many radiolarian chert flakes are imbedded. This layer seems to have slipped off the slanting lakeshore so that the close-up range of a camp respectively a toolmakers workshop can be presumed further up.

All of the spoil was charged with water, spread on canvas cover and searched for artefacts. The remaining material was piled to a cone and added up to almost one cubic metre pure radiolarian chert waste related to the 24 sqm wide - and on average 20 cm deep - excavation area.

In adjacency to the excavation site there are several intentional constructed semicircular and circular stone settings whose purpose are yet unexplained. The archaeological investigations provided no further information. The whole excavation site was surveyed with a theodolite, digital photographs taken and by means of AutoCAD and Photoplan retrificated. With the help of the Institute for Fundamentals of Civil Engineering the position of the excavated area is integrated into the regional coordinates.

First results verify the quantitative and qualitative significant flint resources in the entire Rofan Mountains and their earliest usage by Mesolithic hunters-gatherers. The area around the Grubalacke proves to have notably abundant finds and possibly resembles a central site for the prehistoric utilization of flint resources in the lower Inn valley.        

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