ABSTRACT Geoheritage documentation is critical for the academic community, and thus incurs an expense to the general public, who may or may not feel the need to fund such an “academic” database. Fortunately, this documentation helps foster appreciation of geosites within a geotouristic framework and can inspire a nationalistic sense of pride, thus bringing about an economic incentive to countries actively involved in geoheritage research and documentation. Yet there remains a prejudice within academia that geoheritage is a descriptive field, is arbitrarily qualitative, and lacks the capacity to create new and important scientific discoveries. We present herein a description and discussion of the results of applying “cutting-edge” science in a geoheritage framework with ample examples from Greece and two case studies of its application. The first of these is The Aliakmon Legacy Project of Northern Greece that necessitated modern documentation to preserve its heritage base when plate tectonic global geoheritage localities were flooded. The second summarizes the geologic history of the Meteora World Heritage Site with an emphasis on how its long complex geologic history ultimately resulted in the Byzantine Monastic community. We propose this paper as a discussion model for the integration of primary geologic research with cultural heritage localities and emphasize that these promise to elevate geoheritage studies to a scale critical for documentation of human civilization itself. It is our opinion that geoheritage is capable of becoming a dynamic field of study in which documentation and preservation expands to integrate renewed multidisciplinary research that in turn comprises the scientific foundation of a “new” cutting-edge geologic field of study.

ABSTRACT The “petrological Moho” recognized in the Jurassic Vourinos Ophiolite (northern Greece) was the first “crust-mantle” boundary described within a fossil oceanic lithosphere. Early observations suggested a Cenozoic brittle-field block rotation of the petrological Moho transition area resulting in an oblique clockwise rotation of ~100°, but a brittle fault system responsible for the mechanism of this rotation was never located. A modern interpretation of research dating from the 1960s to the present documents the occurrence of a diverse set of ductile structures overprinting this primary intra-oceanic feature. The following observations from our original “Moho” studies in the Vourinos complex are still pertinent: the contact between the upper mantle units and the magmatic crustal sequence is in situ and intrusional in nature; high-temperature intragranular ductile deformation (mantle creep at temperatures from around 1200 °C down to ~900 °C) fabrics terminate at the crust-mantle boundary; the overlying oceanic crustal rocks display geochemical fractionation patterns analogous to crustal rocks in the in situ oceanic lithosphere. Since these original studies, however, understanding the mechanisms of ductile deformation and ridge crest processes have advanced, and hence we can now interpret the older data and recent observations in a new paradigm of oceanic lithosphere formation. Our major interpretational breakthrough includes the following phenomena: lower temperature, intergranular deformation of ~900 °C to 700 °C extends from the upper mantle tectonites up into the lower crustal cumulate section; the origin of mineral lineations within adcumulate crustal rocks as remnants of ductile deformation during early phases of magmatic crystallization; syn-magmatic folding and rotation of the cumulate section; the tectonic significance of flaser gabbro and late gabbroic intrusions in the crustal sequence; and the relevance and significance of a cumulate troctolite unit within the crustal sequence. These observations collectively point to an important process of a ductile-field, syn-magmatic rotation of the Moho transition area. The most plausible mechanism explaining such a rotation is proto-transform faulting deformation near the ridge crest. By recognizing and distinguishing structures that resulted from such initial rotational deformation in the upper mantle peridotites of ophiolites, future field-based structural, petrographic, and petrological studies can better document the mode of the initiation of oceanic transform faults.

Abstract The Allchar Au-As-Sb-Tl deposit is situated in the western part of the Vardar zone, the main suture zone along the contact between the Adriatic and the Eurasian tectonic plates. It is spatially and temporally associated with a Pliocene (~5 Ma) postcollisional high-K calc-alkaline to shoshonitic volcano-plutonic center. The Allchar deposit shares many distinctive features with Carlin-type gold deposits in Nevada, including its location near a terrain-bounding fault in an area of low-magnitude extension and intense magmatism. The mineralization is mostly hosted in calcareous sedimentary rocks at intersections of high-angle faults in permeable stratigraphy. The alteration types (carbonate dissolution, silicification, and argillization), ore mineralogy (auriferous arsenian pyrite and marcasite, stibnite, realgar, orpiment, and lorandite), high Au/Ag ratios, and low base metal contents are also typical of Carlin-type gold deposits in Nevada. However, the Allchar deposit differs from Nevada Carlin-type gold deposits as follows: it is an isolated Au prospect with a close spatial and temporal relationship to a shoshonitic volcano-plutonic center in a mineral belt dominated by intrusion-related Cu-Au porphyry, skarn, and hydrothermal polymetallic deposits. The deposit is clearly zoned (proximal Au-Sb to distal As-Tl), it has a significantly higher Tl content, trace elements in pyrite and marcasite are homogeneously distributed, and synore dolomitization is a widespread alteration type. Gold mineralization is most abundant in the southern part of the deposit. It occurs mostly as invisible Au in disseminated pyrite or marcasite and as rare native Au grains. Gold mineralization is accompanied by intense decarbonatization and silicification. Fluid inclusions and the hydrothermal alteration mineral assemblage indicate that Au was deposited from hot (>200°C), saline (up to ~21 wt % NaCl equiv), moderately acidic (pH <5) fluids that carried traces of magmatic H 2 S and CO 2 . In the calcareous host rocks, mixing of such fluids with cool, dilute, near-neutral groundwater triggered deposition of Au and Fe sulfides. In Tertiary tuff, isocon analysis shows that sulfidation of preexisting Fe minerals was a critical factor for deposition of Au and Fe sulfides. Antimony mineralization prevails in the central part of the deposit, and it is mostly associated with dark-gray to black jasperoid. Stibnite, the most common Sb mineral in the Allchar deposit, occurs as fine-grained disseminations in jasperoid and as fine- to coarsely crystalline masses that fill vugs and fracture zones lined with drusy quartz. Fluid inclusions entrapped by stibnite-bearing jasperoid, quartz, and calcite crystals suggest that stibnite was deposited from more dilute and cooled fluids (aqueous-carbonic fluid inclusions: 6.0–3.5 wt % NaCl equiv, T h = 102°−125°C; aqueous fluid inclusions: 14.5 and 17.1 wt % NaCl equiv, T h = 120°−165°C). In contrast to stibnite, As sulfides (orpiment and realgar) and Tl mineralization are associated with argillic alteration. Fluid inclusions hosted by realgar, orpiment, dolomite, and lorandite record deposition from more dilute (2.6–6.9 wt % NaCl equiv) and relatively cold fluids (T H = 120°−152°C) enriched in K. Isocon diagrams show a tight link between Tl and the low-temperature argillic alteration as well as a significant correlation between Tl and K. The spatial relationship of Tl mineralization with dolomite suggests that Tl deposition was also promoted by neutralization of acidic fluids. The δ D and δ 18 O data obtained from gangue minerals and fluid inclusions indicate that magmatic fluid mixed with exchanged meteoric water at deep levels and with unexchanged meteoric water at shallow levels in the system. The δ 13 C and δ 18 O values of carbonate minerals and extracted fluid inclusions suggest mixing of carbonate rock buffered fluids with magmatic and atmospheric CO 2 . The sulfur isotope values of early disseminated pyrite and marcasite show that H 2 S was initially derived from diagenetic pyrite in sedimentary rocks. In contrast, Sb and As mineralization indicate a strong input of magmatic H 2 S during the main mineralization stage. Late-stage botryoidal pyrite and marcasite are depleted in 34 S, which indicates a diminishing magmatic influence and predominance of sulfur from sedimentary sources during the late-mineralization stage. Fractionation of isotopically light sulfide species from isotopically heavy sulfates due to oxidation under increased oxygen fugacity cannot be excluded.