Upright Tree Research Articles

An estuarine model for Pennsylvanian Lagerstätten

Estuaries were important sites of deposition throughout most of the Pennsylvanian in the Midcontinent. Modern estuaries typically occur within flooded river valleys where marine and fresh waters mix. Characteristic estuarine circulation results in locally high rates of deposition of muddy sediment that can lead to good preservation of fossils. Several Pennsylvanian conservat-Lagerstätten are best interpreted as having formed within ancient estuaries. Three types of estuarine deposits have been identified. Type 1 estuarine systems are large-scale transgressive systems that start with fluvial sands overlying an erosional surface. This is overlain successively by middle-estuarine laminated mudstone, and finally marine mudstone and shale. Well-preserved fossils occur in laminated mudstones and siltstones. This sequence may include within in it type 3 estuarine Lagerstätten. An example is the Douglas Group (Missourian, Kansas).Type 2 estuarine Lagerstätten consist of thin estuarine deposits confined to narrow paleochannels. This includes the Garnett (Missourian, Kansas) and Hamilton (Virgilian, Kansas) deposits, both of which contain articulated vertebrates and well-preserved plants. Both channels are filled with mixed siliciclastic and carbonate sediments. Fine grained facies from which the best fossils are recovered in both contain evidence of tidal deposition, although tidal rhythmicity is best developed in the Hamilton channel. Plant assemblages in both are dominated by the conifer Walchia, probably indicating a relatively dry climate.Type 3 estuarine Lagerstätten consist of thick gray-shale wedges that overlie coals. The best-known example is the Francis Creek Shale (Desmoinesian, Illinois). A relatively wet climate is indicated by abundant fern and seed-fern foliage. Laminations in shale facies commonly show well-developed tidal rhythmicity. A typical stratigraphic succession starts with laminated shale overlying coal. This grades upwards into flaser and lenticular bedding to ripple and then large-scale cross-bedded sandstone. Upright trees rooted in the coal indicate rapid burial. Well-preserved fossils are recovered from early-diagenetic siderite concretions from the laminated shale.Preservation of fossils is best in laminated mudstones deposited in middle-estuarine environments where conditions are ideal for good preservation. In all cases so far studied the zones of best preservation are well laminated and have sparse (if any) burrows and sessile benthic fossils. Most of the well-preserved organisms are terrestrial, nektonic, or at least mobile. Brackish and fluctuating salinities restricted scavenging and burrowing organisms that may scatter skeletons. High turbidity and deposition rate may have further discouraged many organisms. Matching bedding rhythmicity with tidal cycles allows calculation of depositional rates of 1 cm or more of compacted sediment per 2-week neap-spring tidal cycle. This is consistent with the high rates of deposition known from modern tidal environments. High depositional rates assured that any organism that fell to the sea floor was buried in a few hours to a few days. Once buried anoxic conditions established around decaying carcasses may have led to early mineralization.

Nodular Remains of Early Tertiary Forests, Bighorn Basin, Wyoming

Orange calcareous nodules are widespread in Lower Tertiary alluvial paleosols in the Bighorn Basin, Wyoming. The nodules are abundant at specific stratigraphic levels where they form distinctive and laterally extensive bands. Many are preserved as erect, crudely shaped cylinders a few centimeters to more than 1 m high and generally 10-30 cm in diameter. At two stratigraphic levels in the sequence, hands of cylindrical nodules occur in close association with upright and well-preserved fossil tree stumps. The stumps, which show a distinctive tree-ring growth pattern, are orange in color and permineralized with calcite. The physical proximity and morphologic similarities between the calcified tree stumps and calcareous nodules suggest that the nodules are simply additional, albeit more poorly preserved, tree stumps. Their widespread occurrence in specific horizons suggests that the nodules are the remains of Tertiary forests that grew on stable land surfaces. Although fossil forests can be readily recognized by the presence of upright permineralized trees, such occurrences are rare. The nodular horizons described here provide a new means of determining the location and stratigraphic position of ancient forests.

Sedimentary Processes, Vertical Stratification Sequences, and Geomorphology of the Roaring River Alluvial Fan, Rocky Mountain National Park, Colorado

ABSTRACT The Roaring River alluvial fan formed on 15 July 1982, in Rocky Mountain National Park, Colorado, by a catastrophic flood that was generated by a dam failure. The fan covers an area of 0.25 square km, has a radial length of 0.7 km, and is up to 14 m thick. Sedimentation occurred in three phases, each producing a distinct fan lobe. Initial sedimentation was by a noncohesive sediment-gravity flow which deposited two levees on the proximal boundaries of Lobe I. The levees consist of a poorly sorted mixture of logs, sand, pebbles, cobbles, and boulders. The first two lobes were built primarily by sheetflooding, which deposited imbricated boulders in trains behind obstacles that formed as jams between boulders or logs and upright trees. Horizontally laminated granule and sand sedimentation took place down-fan from the boulders due to deceleration of the expanding sheetflood. Thin-to-medium interbedded sand and cobble-pebble gravel couplets were deposited by sheetflooding on the third lobe. Gravel was transported as bedload by supercritical flow and deposited locally where antidunes broke. Sand was transported as suspended load and deposited where flood velocity locally decreased due to destruction of antidunes, increased roughness, or flow separation around the low-amplitude gravel bed forms. The flood rechannelized at the distal end of Lobe III due to constriction between the fan and the valley margin. Deposits in the upper rechannelized reaches consist of crudely bedded cobble and pebble gravel, and interstratified pebble gravel and backset-bedded sand. Deposition was by supercritical flow. In the lower reaches, planar-cross-bedded, sandy pebble gravel and climbing ripple, horizontal, trough-cross-bedded, and backset-bedded sand were deposited by supercritical and subcritical flow. The flood deposit was modified during waning flood stage and during the three years following the flood by noncatastrophic discharge events. These events formed braided distributary channels by erosion into the top of the sheet flood deposits. Fan building took place mostly by catastrophic unconfined discharge, whereas much of the present fan surface consists of braided channels that formed by erosion into the sheetflood deposits by noncatastrophic discharge.

Yellowstone fossil forests: New evidence for burial in place

Research Article| March 01, 1984 Yellowstone fossil forests: New evidence for burial in place Richard F. Yuretich Richard F. Yuretich 1Department of Geology and Geography, University of Massachusetts, Amherst, Massachusetts 01003 Search for other works by this author on: GSW Google Scholar Author and Article Information Richard F. Yuretich 1Department of Geology and Geography, University of Massachusetts, Amherst, Massachusetts 01003 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1984) 12 (3): 159–162. https://doi.org/10.1130/0091-7613(1984)12<159:YFFNEF>2.0.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Richard F. Yuretich; Yellowstone fossil forests: New evidence for burial in place. Geology 1984;; 12 (3): 159–162. doi: https://doi.org/10.1130/0091-7613(1984)12<159:YFFNEF>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Evidence from stratigraphic relationships and petrographic analyses indicates that most upright tree stumps at Specimen Ridge in Yellowstone National Park were buried in place. These stumps are commonly rooted in a fine-grained tuffaceous sandstone that shows no petrographic evidence of being deposited by current action; in fact, most sandstones have textures resembling immature soils. Conglomerates that overlie these root-zone sandstones flow around and bury the vertical trunks. Trees were apparently killed in place by either mudflows or rising lake waters, giving rise to discontinuous, localized clusters of preserved trees in a given stratigraphic interval. However, the episodic nature of mudflow sedimentation indicates that these stacked clusters are likely remnants of successive forests with enough time between them to allow for incipient soil development. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Growth Habits of Five Cultivars of Pyrus Calleryana

Callery pears are upright trees with 3 bad crotch angles and 36 branches in the first 5 feet of the crown. High branch density and narrow crotch angels make this plant very prone to storm damage. The cultivar 'Aristocrat' has fewer crotches and a lower branch density, which suggests that this plant may have fewer problems as the plant matures in the landscape. Graphic representations for 5 cultivars are presented and are drawn to scale to allow direct comparison between cultivars for height, width, and habit.

Alluvial fan and lacustrine sediments from the Stephanian A and B (La Magdalena, Ciñera—Matallana and Sabero) coalfields, northern Spain

ABSTRACTVertical sequence analysis within 1500‐2500 m thick coarse‐grained coalfield successions allows six sedimentary associations to be distinguished. These are interpreted in terms of depositional environments on, or related to alluvial fans which fringed a fault bounded source region. (i) Topographic valley and fanhead canyon fills: occurring at the bases of the coalfield successions and comprising sporadically reddened, scree, conglomeratic thinning and fining upward sequences, and fine‐grained coal‐bearing sediments. (ii) Alluvial fan channels: conglomerate and sandstone filled. (iii) Mid‐fan conglomeratic and sandstone lobes: laterally extensive, thickly bedded (1‐25 m) and varying from structureless coarse conglomerates and pebbly sandstones, to stratified fine conglomerates and cross‐bedded sandstones. (iv) Interlobe and interchannel: siltstones, fine‐grained sheet sandstones, abundant floras, thin coals and upright trees. (v) Distal fan: 10 cm‐1.5 m thick sheet sandstones which preserve numerous upright trees, separated by silt‐stones and mudstones with abundant floras, and coal seams. The sheet sandstones and normally arranged in sequences of beds which become thicker and coarser or thinner and finer upwards. These trends also occur in combination. (vi) Lacustrine: coals, limestones, and fine‐grained, low‐energy, regressive, coarsening upward sequences.Proximal fan sediments are only preserved in certain basal deposits of these coalfields. The majority of the successions comprise mid and distal alluvial fan and lacustrine sediments. Mid‐fan depositional processes consisted of debris flows and turbulent streamflows, whilst sheetfloods dominated active distal areas. A tropical and seasonal climate allowed vegetation to colonize abandoned fan surfaces and perhaps resulted in localized diagenetic reddening. Worked coals, from 10s cm‐20 m thick, occur in the distal fan and lacustrine environments.These alluvial fan deposits infill‘California‐like’basins developed and preserved along major structural zones. In many of their characteristics, in particular the occurrence of thinning and fining, and thickening and coarsening upward sequences and megasequences, these sediments have similarities to documented ancient submarine fan deposits.

RATES OF SEDIMENTATION IN THE UPPER CARBONIFEROUS OF BRITAIN

Rate of sedimentation of the Gastrioceras cancellatum marine band (Namurian) is deduced from evidence of shell size, population density, and features of the enclosing sediment. Slowest sedimentation apparently coincided with stagnant water conditions. But in a non-marine succession (Coal Measures) containing trees fossilised upright and rooted in position of growth, the rate of sedimentation (on the evidence of sediments and fossils) is found to be unrelated to degree of water turbulence (sediments and geochemistry). The upright trees were apparently overwhelmed rapidly by sediments deposited from a succession of floods characterised by a wide range of water turbulence.

Narrow Upright Trees in the Arnold Arboretum

Narrow Upright Trees in the Arnold Arboretum

Fossil Plants as Tests of Climate

MR. J. STARKIE GARDNER, in his interesting review of Mr. Seward's valuable essay, makes a statement which I fancy may be misinterpreted at page 268 of NATURE, where he speaks of the fragmentary character of the Arctic tertiary plants, and the inexperience of the collectors. He doubtless is referring to the remains of certain supposed “palms and cycads in the Greenland Eocene,” but those who have not followed this branch of Arctic research would hardly gather from the review that Prof. Heer has determined a magnificent flora of more than 350 species from these northern tertiaries, and that he at once pointed out the absence of tropical and subtropical forms, and the fact that large leaves are not only perfectly preserved up to their edges, but that upright trees associated with their fruits and seeds prove them to have grown on the spot. “Thus of Sequoia Langsdorffi,” he writes, “we see not only the twigs covered with leaves, but also cones and seeds, and even a male catkin”.1

On the Remains of a Reptile (Dendrerpeton Acadianum, Wyman and Owen) and of a Land Shell discovered in the Interior of an Erect Fossil Tree in the Coal Measures of Nova Scotia

Descriptions and sections of the Coal-formation of Nova Scotia, and particularly of the cliffs called the South Joggins, have been published by Messrs. Jackson and Alger*, Mr. Brown†, Dr. Gesner‡, Sir C, Lyell §, and Mr. Logan ∥. In September last (1852) the authors of the present notice re-visited and re-examined the strata in a part of these cliffs, with a view of ascertaining what may have been the particular circumstances which favoured the preservation of so many fossil trees, at so many different levels, in an erect position; such a position being a rare and very exceptional fact in the coal strata of North America generally. We were also desirous of obtaining additional evidence on a point which is still a matter of controversy in the United States and elsewhere (although we ourselves were already satisfied with the evidence adduced by Mr. Binney¶ and others), namely, the relation of Stigmaria , as a root, to Sigillaria . We also directed our special attention to the difference of the deposits enveloping the upright trees, and those which fill the trunks themselves, forming casts within a cylinder of bark now turned to coal, the central wood of the trunk having decayed. We searched diligently for fossils in these stony casts, suspecting that organic bodies preserved in so peculiar a situation might differ from such as are buried in ordinary subaqueous strata. With this object we employed a labourer to dig out many vertical trees from the cliffs, so that we might break them

Description of an upright Lepidodendron with Stigmaria Roots, in the roof of the Sydney Main Coal, in the Island of Cape Breton

Many eminent geologists have long entertained the opinion, that Stigmariæ are nothing more than the roots of Sigillariæ, and this opinion has been supported by so many recorded cases during the last two or three years, amongst which I may include one from the Sydney coal-measures, an account of which appeared in the 8th Number of the Journal of the Geological Society, that I think no further doubts can remain concerning the real nature of those fossils. Since I forwarded to the Society a description of the Sydney Sigillaria about twelve months ago, I have discovered several upright trees in the coal-measures, evidently not Sigillariæ, with roots of Stigmariæ united to them. These trees exhibited so many of the peculiar characteristics of Lepidodendron, that I at once concluded they belonged to that genus; but having never even seen it hinted that Lepidodendron possessed Stigmaria roots, and distrusting my own skill in fossil botany, I determined to wait until I could collect more decisive evidence in confirmation of my opinion. This evidence I have now obtained in another example, fortunately most complete in all its parts, a description of which I hasten to lay before the Society, accompanied with sketches, which I hope will clearly prove that the stem in question is a genuine Lepidodendron united to roots of Stigmaria.