Re-evaluation of the Mesozoic complexes of
Darnó Hill (NE Hungary) and comparisons with
Neotethyan accretionary complexes of the
Dinarides and Hellenides – preliminary data
Abstract
The Mesozoic complex of Darnó Hill area in NE Hungary, according to well core documentation,
is made up of two units. The upper unit, the Darnó Unit s.s., consists predominantly of blocks of
ophiolitic rocks (pillow and massive basalt, gabbro) and subordinate abyssal sediments (red
radiolarite and red pelagic mudstone of either Ladinian–Carnian or Bathonian–Callovian age, as well
as bluish-grey, sometimes blackish siliceous shale of the latter age). The basalt is geochemically of
MOR type, based on earlier evaluations. However, it comes in two types: reddish or greenish
amygdaloidal pillow basalts with peperitic facies containing reddish micritic limestone inclusions,
and green basalts without any sedimentary carbonate inclusion. The former type is probably MiddleTriassic,
advanced rifting stage-related basalt, whereas the latter is probably of Jurassic age,
corresponding to the Szarvaskõ-type basalt of the western Bükk Mountains. Pre-Miocene presence of
an ultramafic sheet above the complex is indicated by serpentinite pebbles in the Lower Miocene
Darnó Conglomerate.
The lower unit, corresponding to the Mónosbél Unit of the western Bükk Mountains, consists of
lower slope and toe-of-slope type sediments: dark grey shale and bluish-grey siliceous shale of
Jurassic age, both showing distal turbiditic character, with frequently interbedded carbonate
turbidites and debris flow deposits containing cm- to dm-sized limestone and micaceous sandstone
clasts. One to ten m-sized slide blocks of reddish, siliceous Triassic Bódvalenke-type limestone
associated with the above-mentioned reddish, amygdaloidal basalt also occur. In one of the studied
cores a block comprising evaporitic siliciclastics akin to those of the Middle Permian Szentlélek
Formation and black, fossiliferous limestone similar to the Upper Permian Nagyvisnyó Limestone
Formation of the Bükk Mountains, was also encountered.
A preliminary comparison with similar Triassic advanced rifting-type basalt and limestone/
radiolarite of the western ophiolite zone of the Balkan Peninsula is presented (Fig. 1): the Zagorje
region of NW Croatia, the Zlatibor-Zlatar Mountains of SW Serbia, and the North Pindos and Othrys
Mountains, as well as Euboea Island, of Northern Greece. We propose the terms "Loggitsi Basalt" for
such Triassic basalt containing peperitic facies, after the village of Loggitsion located in the central part
of the Othrys Mts, and "Bódvalenke Limestone" for the transitional facies between Hallstatt
Limestone and Triassic red radiolarite, after the village of Bódvalenke located in the Rudabánya Hills.
The northwesternmost occurrence of both of these typical Neotethyan formations can be found in NE
Hungary (Darnó Hill and Bódva Unit of Rudabánya Hills, respectively)