Northern Cascade Range Research Articles

Flavonol Glycoside Variation in Diploids of the Claytonia perfoliata Complex (Portulacaceae)

Three allopatric, morphologically distinct diploid species and their auto- and allopolyploid derivatives constitute the Claytonia perfoliata complex. Diploid C. rubra synthesizes kaempferol-3-O-glucoside, kaempferol-3-O-arabinosylglucoside, and novel kaempferol-3-O-rhamnosylarabinosylglucoside. Claytonia perfoliata dip- loids yield the same array of glycosides but both kaempferol and quercetin are glycosylated. Unlike the autogamous C. rubra or C. perfoliata, the facultatively xe- nogamous diploid C. parvflora makes abundant diglycosides of kaempferol and quercetin including rhamnosylglucosides, arabinosylglucosides, and a glucosylglu- coside. In all three taxa flavonol-3-O-glycosides show little interpopulational varia- tion and are localized in floral tissue. Flavonoid data support a multi-species general- purpose classification for the C. perfoliata complex. Considerable descriptive information that unravels the morphological and cytological complexity of the myriad of forms attributable to the Claytonia perfoliata complex has been published (Miller 1976, 1978). Dip- loid populations of Claytonia parviflora Hook., C. rubra (T. Howell) Ti- destr., and C. perfoliata Willd. have been clearly distinguished on mor- phological grounds. Each diploid occupies a different, well-defined habitat. Diploid, annual C. perfoliata is autogamous and widely scattered in moist, naturally disturbed sites over a 3000 km geographic range from low elevations in the California Coast, Transverse, and Peninsular ranges, through mid-elevations in the Sonoran Desert mountains of southern Arizona, to high elevation coniferous forests of the Sierra Madre Occidental and Trans-Mexican Volcanic Belt. High polyploids of this species occur as a disjunct population in the Guatemalan Highlands. In contrast, diploids of C. parviflora are facultatively xenogamous annuals that occur sporadically within the foothill woodland belt of the California Sierra Nevada. A third diploid, C. rubra is obligately autogamous and grows in disturbed coniferous and sagebrush woodlands or along water- courses in the western Rocky Mountains, northern Great Basin, Cascade Range, Klamath Mountains, and Sierra Nevada. This species, at the dip- loid level, reaches a southern limit at high elevations on Mt. Pinos in the California Transverse Ranges. This paper presents evidence that each diploid taxon displays a distinct

Corrigenda: Multiple Ice Flow Directions during the Fraser Glaciation in the Lower Skagit River Drainage, Northern Cascade Range, Washington

Corrigenda: Multiple Ice Flow Directions during the Fraser Glaciation in the Lower Skagit River Drainage, Northern Cascade Range, Washington

Multiple Ice Flow Directions during the Fraser Glaciation in the Lower Skagit River Drainage, Northern Cascade Range, Washington

Multiple Ice Flow Directions during the Fraser Glaciation in the Lower Skagit River Drainage, Northern Cascade Range, Washington

Multiple Ice Flow Directions during the Fraser Glaciation in the Lower Skagit River Drainage, Northern Cascade Range, Washington

Multiple Ice Flow Directions during the Fraser Glaciation in the Lower Skagit River Drainage, Northern Cascade Range, Washington

Regional Metamorphism, Metasomatism, and Partial Fusion in the Northwestern Part of the Okanogan Range, Washington

The northwestern part of the Okanogan Range, Washington, (in the vicinity of 49°00 ′N., 120°00′W.) comprises regionally metamorphosed rocks, largely of supracrustal origin, plus igneous rocks ranging in composition from quartz diorite to quartz monzonite. Metamorphic rocks include quartz dioritic to trondhjemitic orthogneisses, biotitic and hornblendic schists, gneisses and hornfelses, amphibolites, and calc-silicate gneisses. Mineral assemblages indicate that the region was metamorphosed more or less uniformly under conditions equivalent to the sillimanite-cordierite-orthoclase-almandine subfacies (cordierite amphibolite facies) with possible local transition to granulite facies. The presence of andalusite plus sillimanite indicates metamorphism of the Abukuma type (andalusite-sillimanite facies series) in contrast to the kyanite-sillimanite facies series in the Northern Cascade Range to the west. A single cycle of synkinematic metamorphism followed by a phase or separate cycle of static recrystallization in essentially the same P-T field is shown by rock textures and mineral assemblages. The parent material of the metamorphic rocks included mafic flows, sills and dikes, intermediate composition volcanic rocks and graywackes, minor amounts of carbonate-rich and pelitic sedimentary rocks plus an indeterminate amount of leucocratic igneous rock. Prior to metamorphism the average composition of the parent material was approximately tonalitic. The igneous rocks include intrusive granodioritic and quartz monzonitic rocks (average composition is granodiorite) of the Cathedral batholith (Daly, 1912) with an apparent age of 94.0 ± 2.8 m.y. (K/Ar date on biotite) and older trondhjemitic to leucogranodioritic rocks. The older igneous series comprises partly gneissose syntectonic intrusive rocks, and directionless late to post-tectonic rocks which lack intrusive contacts. The latter are interpreted as anatectites formed by (partial) fusion of rocks of quartz dioritic to trondhjemitic composition during regional metamorphism. Field and petrographic data indicate that the anatectites have not been deformed. The average chemical composition of the older igneous series is trondhjemitic. A small layered gabbroic pluton, characterized by iron-rich olivine and pyroxene, has intruded the metamorphic series. Its age relative to the Cathedral batholith is not known. The metamorphism was pre-late Cretaceous and, by analogy with surrounding areas, probably was pre-mid Jurassic but post-Paleozoic. The age of the eugeosynclinal rocks, which were parent materials for the metamorphic rocks, is unknown, but a mid- to late-Paleozoic age is suggested by comparison with rocks of known age in adjacent areas. These eugeosynclinal rocks were definitely sialic, their average composition being tonalitic. A comparison between the average chemical composition of the metamorphic rocks and syn-metamorphic plutons and the average composition of eugeosynclinal rocks of the Pacific rim, such as graywackes, suggests that the rocks of the Okanogan Range may have been formed by nearly isochemical metamorphism of eugeosynclinal sedimentary and volcanic rocks.

Mazama and Glacier Peak Volcanic Ash Layers: Relative Ages

Physiographic and stratigraphic evidence supports the regional correlation of two volcanic ash layers with extinct Mount Mazama at Crater Lake, Oregon, and Glacier Peak in the northern Cascade Range of Washington. A radiocarbon age of 12,000 +/- 310 years confirms geological evidence that ash derived from the Glacier Peak eruption is substantially older than ash from the Mazama eruption of 6600 years ago.

COMPOSITE PLEISTOCENE SNOW LINE OF OLYMPIC MOUNTAINS AND CASCADE RANGE, WASHINGTON

A composite Pleistocene snow line for the Olympic and Cascade ranges, based on altitudes of lowest north-facing cirques, increases in altitude inland (east or northeast) in both ranges. In the Cascade Range of southern Washington the rate of inland rise of Pleistocene cirque floors approximately equals that of small alpine glaciers. This relationship suggests that lower temperature may have been the primary factor controlling depression of the snow line during glaciations in this region. In the northern Cascade Range and in the Olympic Mountains, however, the eastward rise of Pleistocene cirque floors is steeper than that of small modern glaciers suggesting that significant reduction in precipitation at glacial maxima in those two areas offset the effects of decreased temperature, and the snow line was depressed differentially. Very likely this reduction in precipitation resulted largely from strong local climatic influences exerted by the Puget Lobe of the Cordilleran Glacier Complex that extended into the lowland between the Olympic Mountains and Cascade Range during successive glaciations.