Boron is a biologically important element, but its distribution in the natural environment and its behavior during many geological processes is not fully understood. In most metamorphic and igneous environments, boron is incorporated into minerals of the tourmaline supergroup. In high-grade metamorphic terranes like that of the Adirondack region of northern New York State, uncommon rock compositions combined with unusual and variable geologic conditions resulted in the formation of many additional boron-bearing minerals. This paper reviews the occurrences and geological settings of twelve relatively uncommon boron-bearing minerals in the southern Grenville Province of upstate New York and provides new chemical and Raman spectral data for seven of these minerals. The boron minerals range from relatively simple metal borates (e.g., vonsenite), to chemically complex borosilicates (e.g., prismatine), to a relatively rare borosilicate-carbonate (e.g., harkerite). Some are of primary igneous origin, while others are formed by a variety of prograde and retrograde metamorphic processes or by metasomatic/hydrothermal processes. Most of the boron minerals are formed within, or adjacent to, metasedimentary lithologies that surround the anorthositic massifs of the central Adirondacks. The metasedimentary rocks are thought to be the source of most of the boron, although additional boron isotope studies are needed to confirm this and to constrain the mechanisms of the formation of these unusual minerals.
Octopamine synthesized in vitro from tyramine by Limulus lateral and ventral eyes was located by light microscopic and electron microscopic autoradiography in efferent fibers which innervate ventral photoreceptors and lateral eye ommatidia. Newly synthesized octopamine was released from efferent fibers in response to depolarization in high concentrations of potassium. We propose that octopamine is a neurotransmitter of efferent fibers that may modulate basic retinal processes such as photoreceptor sensitivity, photomechanical movements, and photoreceptive membrane turnover.
Witherite BaCO3 occurs in the mineralized septarian frac'tures of concretions in the Chittenango Member of the Marcellus Formation of the Middle Devonian Hamiltou Croup at three occurrences in Onondaga County, New York. The minerals occurring in the septarian fractures, in order of formation, are, pyrite I and calcite I [(Ca6.e6Mg6.o2Ffo .dcOll, calcite II [(Cae.e6Mg6.e2Fe6.6) CO3J and barite, pyrite II, ferroan dolomite [Ca(Mg0.57Fq.a3XCOl)zl and calcite III, quartz, calcite IV [(Ca6.e3Mgs.s1Fee.or)CO:1, strontianite, witherite, calcite V. Both the calcite matrix [(Can.eMgb.e2Fq.sl)CO3] of the concretions and the mineralization in the septarian fractures contain abundant hydrocarbon. Like other witherite, this witherite formed from the alteration of barite. The geological setting, however, precludes the normal alteration of barite by hydrothermal solutions rich in carbonate. The composition of the stable isotopes of carbon, in witherite from the septarian concretions, is significantly enriched in the heavy isotope l3C (+2.11700<613C .< +14.77y@PDB) compared to wilherite from 26 other worldwide localities (-29.41o/oo s 6l3C s +l.l6o/ffi PDB). These data suggest that this witherite formed as the result of sulfate reduction and methane fermentation by bacteria in anoxic groundwaters. This represents both a new mode of occurrence for witherite and a new mechanism for its formation from barite.
