The latitudinal distributions in Devonian-Cretaceous ammonoids were analyzed at the genus level, and were compared with the hatchling sizes (i.e., ammonitella diameters) and the geological durations. The results show that (1) length of temporal ranges of ammonoids effected broader ranges of fossil distribution and paleobiogeography of ammonoids, and (2) the hatchling size was not related to the...

In the Dusina area, which is built up of Lower Palaeozoic metasediments, Devonian carbonate complex and Upper Palaeozoic metarhyolites unconformably overlain by Upper Permian sediments, numerous ore occurrences have been investigated: (a) "stratabound" metamorphic hematite deposits in the pre-Devonian metasediments; (b) epigenetic veins and pipes of barite (& calcite) with accessory Hg-tetrahed...

The NE-trending multiphase Late Devonian Eagle Lake granite (ELG) in southwestern New Brunswick is mineralized, consisting of hypabyssal porphyritic stocks and dikes that intruded Silurian metabasic volcanic rocks; however, its various phases, ages, associations with notable stockwork Cu–Mo–Au mineralization alteration have yet to been studied. ELG suite predominantly composed phenocrysts a mic...

Water and gas samples were collected from (1) nine shallow groundwater aquifers overlying Marcellus Shale in north-central West Virginia before active shale gas drilling, (2) wells producing gas from Upper Devonian sands and Middle Devonian Marcellus Shale in southwestern Pennsylvania, (3) coal-mine water discharges in southwestern Pennsylvania, and (4) streams in southwestern Pennsylvania and ...

Dispersed microfossils (spores and phytodebris) provide the earliest evidence for land plants. They are first reported from the Llanvirn (Mid-Ordovician). More or less identical assemblages occur from the Llanvirn (Mid-Ordovician) to the late Llandovery (Early Silurian), suggesting a period of relative stasis some 40 Myr in duration. Various lines of evidence suggest that these early dispersed ...

Kimberlite in the Mengyin area serves as an excellent medium for studying characteristics and evolutionary processes of Paleozoic mantle. In order to determine age primary calcite within kimberlite, situ carbonate U–Pb dating was conducted area. The results indicate that kimberlite originated approximately 383 ± 18 Ma (MSWD = 6.6). This constraint suggests eruption took place during this period...