Earth History Research and News

Impact-related soft-sediment deformation in the UK Triassic?

2007-01-23T08:29:00.000-08:00

In the latest issue of Palaeogeography, Palaeoclimatology, Palaeoecology a new explanation is offered for an extraordinarily widespread horizon of soft-sediment deformation in the lower part of the Cotham Member of the Penarth Group (latest Triassic, Rhaetian). The most parsimonious interpretation is for a major seismic event triggering in situ foundering of poorly consolidated sediments, but its exact cause remains enigmatic. The consistent position of the ‘seismite’ horizon in the lower part of the Cotham Member, the lack of any evidence for more than one deformational event, and the absence of similarly widespread phenomena in contiguous parts of the geological column, favour a single-event scenario. The authors argue that volcanism is unlikely to have been responsible and that the impact of a 2-3 km diameter asteroid offers a more attractive explanation for such a powerful seismic shock. However, no impact crater of the right age has yet been located so the bolide impact interpretation remains speculative.

Simms, M. J., ‘Uniquely extensive soft-sediment deformation in the Rhaetian of the UK: evidence for earthquake or impact?’, Palaeogeography, Palaeoclimatology, Palaeoecology 2007;244(1-4):407-423.

Abstract. The lower part of the Cotham Member in the Penarth Group (latest Triassic, Rhaetian) of the UK incorporates a uniquely extensive metre-scale horizon of soft-sediment deformation. Interpreted as a seismite, it shows evidence for only a single seismic event even at its thickest development. It is recorded from more than forty sites across at least eight discrete sedimentary basins covering > 250,000 km2, and originally must have covered a still larger area. Such a widespread horizon of soft-sediment deformation, unique for the UK Phanerozoic and implying a seismic event of exceptional magnitude, is difficult to account for by conventional terrestrial mechanisms. Contemporaneous volcanism in the Central Atlantic Magmatic Province (CAMP) was too far distant to cause the deformation, and the tectonic setting of the region was not conducive to earthquakes on this scale. Slump fold long axes suggest an epicentre broadly in the southern Irish Sea or St. George's Channel. Impact of a km-scale asteroid here potentially could produce the observed sedimentological effects across the UK, but any late Triassic impact structure would now be concealed by a km or more of younger strata. At its thickest development, in Northern Ireland, the seismite is succeeded by a rip-up breccia and hummocky- and wave-rippled cross stratification. These facies, and their position immediately above the seismite, are consistent with the effects of a tsunami arising directly from the seismic event. Tentative evidence for a tsunamite of this age has also been reported from southern France. The putative tsunamite in Northern Ireland is succeeded by a desiccation-cracked hiatus which may correlate with a similar hiatus truncating the seismite at sites in southern England. The hiatus in southern England correlates closely with a δ13C isotope excursion that has been traced from eastern Europe across to western North America and is associated with significant biotic changes. The ultimate cause of the seismite and associated tsunamite remains unclear. No impact crater of appropriate age or location is currently known and other evidence for impact at this time is at best equivocal. It is considered here that impact of a km-scale asteroid may have caused the observed sedimentological effects in the Lilstock Formation across the UK area, but was not necessarily a significant contributory factor in the generation of either the isotope excursion or of the biotic changes through the Triassic-Jurassic boundary interval.

Green River Formation: articles now on-line

2007-01-10T08:59:00.000-08:00

My blog post for April 19 2006 concerned a debate in the Journal of Creation about whether the Green River Formation (Eocene of Wyoming) was deposited during or after the Flood. Michael Oard argued the case for Flood deposition and John Whitmore argued for a post-Flood lacustrine model. The papers in the debate forum have now been made available on-line. Just follow the link. Each paper can be downloaded as a pdf file.

http://www.creationontheweb.com/content/view/4509/#Forumcontents

Giant tsunami deposits

2007-01-10T08:45:00.000-08:00

Catastrophism is alive and well in the Middle Jurassic of Oman. This paper describes coarse debris flow deposits, incorporating very large floating clasts up to 100 m long. The sediments are interpreted as having been deposited by massive submarine slides, which were then reworked by the resulting tsunami.

Brookfield M. E., Blechschmidt I., Hannigan R., Coniglio M., Simonson B., Wilson G., ‘Sedimentology and geochemistry of extensive very coarse deepwater submarine fan sediments in the Middle Jurassic of Oman, emplaced by giant tsunami triggered by submarine mass flows’, Sedimentary Geology 2006;192(1-2):75-98.

Abstract. Unusual fining upwards coarse conglomerates overlain by sandstones, thin cherts and green shales occur at the top of the deep-water submarine fan deposits of the Oolitic Limestone Member of the Jurassic Guwayza Formation of Oman. They separate the dominantly submarine fan deposits of the Guwayza Formation from the pelagic shales, fine-grained limestones and cherts of the overlying Sidr Formation. The cross-bedded and graded framework conglomerates occur in extensive, tabular units and are dominated by earlier Mesozoic carbonate clasts with sandy oolitic and peloidal grains derived from fault escarpments and shelf sediments far to the southwest. Subordinate inverse grading, very thick beds, very large floating clasts (up to 100 m long in places) indicate deposition from catastrophic debris flows. Though most palaeocurrents indicate flow from off the platform to the southwest, hummocky cross-bedding shows divergent palaeocurrents suggesting movement in part by deep-water waves. The beds are too coarse for antidune formation and the conglomerate to sand hummocks indicate decelerating flow. There are no nearby large objects to deflect turbidity currents to form divergent flows. We consider that the hummocky cross-stratification, like that in shallow water, was formed by interfering waves. That such coarse, tabular conglomerates affected by wave action occur over extensive areas across deep submarine fan environments, suggests deposition by high-velocity seaward-moving debris and grain flows followed by reworking by waves large enough to redistribute coarse sediment in deep water. The only waves large enough are those of giant tsunami. Petrology and geochemistry show no impact or explosive volcanic constituents in the finer units and the waves involved are too large for generation directly by submarine fault displacements. We suggest that the top Guwayza conglomerates were deposited by very large submarine slides which were then reworked by the tsunami generated by them. Such contemporary massive slope failure deposits are present on the adjacent slope and shelf margin.

Rapidly-deposited fine-grained mudflows

2006-09-06T08:19:00.000-07:00

Fine-grained sediments are usually interpreted as accumulating slowly in tranquil environments. However this report of extensive mudflows in the Upper Cretaceous of Madagascar, bearing abundant and well-preserved fossil vertebrates, reminds us that fine-grained sediments can be rapidly deposited.

Rogers R. R., ‘Fine-grained debris flows and extraordinary vertebrate burials in the Late Cretaceous of Madagascar’, Geology 2005;33(4):297-300.

Abstract. Vertebrate fossils are remarkably abundant and exceptionally well preserved within the Upper Cretaceous Maevarano Formation of northwestern Madagascar. The vast majority of these fossils, including all of the currently known bone beds, are entombed within deposits of fine-grained cohesive debris flows. These deposits are typically massive and are characterized by very poor sorting and a significant montmorillonite-dominated silt-clay (mud) fraction ranging from 17% to 46% by weight. Deposition is attributed to recurrent exceptional rainfall events that prompted erosion and flooded ancient channel belts with sediment-laden flows. These extraordinary burial events shielded vertebrate remains from destructive surface processes and also afforded protection for soft tissues. Taphonomic attributes of associated bone concentrations suggest that debris flows had limited transport potential and generally entombed subaerially exposed bone assemblages. The remarkable and recurrent association of bone beds and debris-flow deposits likely reflects marked seasonality in this Late Cretaceous terrestrial ecosystem, with prolonged dry spells prompting mortality and subsequent rains setting debris flows in motion.

Dinosaur trackways in marine limestone

2006-09-04T13:10:00.000-07:00

This report of dinosaur trackways in a marine limestone will be of interest to those developing catastrophist models of Earth history. The two reported track sites are located near the village of Coisia in the French Jura. Both exposures are subvertical bedding planes showing sauropod footprints impressed in a Jurassic (Tithonian) limestone referred to the 'Couches du Chailley' Formation. The Couches du Chailley are bioturbated by Thalassinoides burrows and have yielded ammonites, gastropods, bivalves, algae and foraminifers. Conventionally they represent a subtidal environment such as a lagoon separated from the open sea by a coral reef. The dinosaur footprints are referred to the ichnogenus Parabrontopodus, attributed to sauropods or diplodocoids.These animals evidently left the tracks on a surface temporarily exposed between marine incursions.

Le Loeuff J., Gourrat C., Landry P., Hautier L., Liard R., Souillat C., Buffetaut E., Enay R., ‘A Late Jurassic sauropod tracksite from Southern Jura (France)’, Comptes Rendus Palevol 2006;5(5):705-709.

Abstract. The discovery of sauropod trackways in the Late Jurassic (Tithonian) of the Jura department (eastern France) is reported. More than 170 footprints (pes and manus prints) comprise at least nine trackways. The footprints are referred to the ichnogenus Parabrontopodus, characterized by a narrow-gauge trackway. The locality of Coisia is the most important sauropod tracksite in France.

Surprisingly rapid magma ascent

2006-05-25T01:53:00.000-07:00

Basaltic magmas from southern Patagonia have brought to the surface xenoliths containing olivine grains with rims that are depleted in hydrogen relative to the central core. The hydrogen profiles represent a dehydration process having occurred during ascent in the host magma. Demouchy et al (2006) have used experimental hydrogen diffusion data to fit the observed profiles, constraining the xenolith’s ascent rate. Surprisingly, some of these xenoliths appear to have reached the surface from 60-70 km depth within several hours.

Demouchy S, Jacobsen SD, Gaillard F, Stern CR, ‘Rapid magma ascent recorded by water diffusion profiles in mantle olivine’, Geology 2006;34(6):429-432.

Abstract: Mechanisms and rates of magma ascent play a critical role in eruption dynamics but remain poorly constrained phenomena. Water, dissolved in mantle minerals as hydrogen and partitioned into the magma during ascent, may provide clues to quantifying magma ascent rates prior to eruption. We determined the dehydration profiles in olivine crystals from peridotite mantle xenoliths within the Pali-Aike alkali basalt from Patagonia, Chile. The results demonstrate that the amount of water stored in the uppermost mantle has likely been underestimated due to water loss during transport. Using experimental diffusion data for hydrogen, we estimate that the xenoliths reached the surface from 60-70 km depth in several hours, a surprisingly rapid rise comparable to ascent rates for kimberlite magmas.

Green River Formation: Flood or post-Flood?

2006-04-19T08:54:00.000-07:00

The latest edition of the Journal of Creation (formerly the TJ), published by Answers in Genesis, includes a forum on whether the Green River Formation (Eocene) was deposited during or after the Flood. Michael Oard argues the case for Flood deposition and John Whitmore argues for a post-Flood lacustrine model. These papers are currently not available on-line but here are the citations with abstracts. For what it’s worth, I’m with Whitmore!

Journal of Creation Editors, ‘Introduction to the Forum’, Journal of Creation 2006;20(1):45.

Oard M.J., Whitmore J.H., ‘The Green River Formation of the west-central United States: Flood or post-Flood?’, Journal of Creation 2006;20(1):46-49.

Abstract. Many creationists believe the Genesis Flood was responsible for the bulk of sedimentary rocks and fossils. However, disagreements often arise in trying to determine where the Flood/post-Flood boundary should be placed in the stratigraphic record. This forum is a friendly exchange between two young-earth creationists who hold differing views on the origin of the Green River Formation (GRF). The authors have examined the rocks in the field together. Mike Oard will defend the thesis that the GRF was deposited in the Flood and John Whitmore will defend the thesis that it is a post-Flood lacustrine (lake) deposit. This paper outlines the geological setting of the GRF.

Oard M.J., ‘The case for Flood deposition of the Green River Formation’, Journal of Creation 2006;20(1):50-54.

Abstract. The Green River Formation (GRF) is a controversial formation within creationist earth science. Evolutionary geologists see the GRF as a sequence of about six million varves deposited with other associated formations over a few tens of millions of years of geological time. Furthermore, these geologists also ‘find’ Milankovitch and sunspot cycles in the ‘varves’. A number of creation geologists have found evidence that has convinced them the GRF formed in a post-Flood lake. The several times I have examined the GRF from a geomorphological point of view, I have come to the conclusion that it was formed during the Flood.

Whitmore J.H., ‘The Green River Formation: a large post-Flood lake system’, Journal of Creation 2006;20(1):55-63.

Abstract. Evidence from lithology, sedimentology, paleontology, ecology, taphonomy, geochemistry and structural geology suggests the Green River Formation (GRF) was a large lake system. Certain features – such as multiple horizons of exploded fish, disarticulated fish and stromatolites – suggest the passage of more than the one year of time allowed for by the Genesis Flood. Since these deposits have multiple lacustrine characteristics, are relatively undeformed compared to the underlying basins on which they rest and since the GRF is near the top of the geologic rock record, it is argued that the GRF represents a post-Flood lacustrine deposit.

Oard M.J., ‘Response to the post-Flood lake model for the Green River Formation’, Journal of Creation 2006;20(1):64-71.

Abstract. Lake paleoenvironmental signatures, as discussed by John Whitmore, are equivocal and thus cannot be considered as valuable as the geomorphological evidences. The exploded fish and caddis fly burrows are challenging to a Flood interpretation, however, other features of the fossil fish and caddis fly burrows are anomalous for a post-Flood lake. An early Flood timing can explain many of the features interpreted to be from a post-Flood setting, such as bird and mammal tracks, raindrop impressions, and mudcracks. Furthermore a case can be made for the inorganic deposition of ‘stromatolites’, and ‘evaporites’ claimed in the Green River Formation (GRF) have anomalous features for a post-Flood lake. A Flood model can explain the deposition and features of the GRF.

Whitmore J.H., ‘The geologic setting of the Green River Formation’, Journal of Creation 2006;20(1):72-78.

Abstract. Further evidence is presented that the Green River Formation (GRF) was deposited after the Flood following the tectonic uplift of Psalm 104:8. A shift from continental-wide to regional sedimentation patterns within local basins makes this clear. Additional evidence suggests the GRF was deposited in a warm lacustrine ecosystem over a period of hundreds of years, suggesting the need to re-evaluate post-Flood climate models. Sedimentological, stratigraphic and structural evidence suggests pediments, developed on GRF basin fills, could not have formed until well after the Flood. For now, creationists should abandon the use of paleontological criteria (index fossils) in defining the post-Flood boundary and focus on sedimentological and stratigraphic criteria instead.

Oard M.J., ‘Geomorphology indicates the GRF was deposited in the Flood’, Journal of Creation 2006;20(1):79-80.

Abstract. Many aspects of geomorphology indicate that the Green River Formation (GRF) was deposited during the Flood. The massive deposition and erosion of the GRF immediately suggests the Flood catastrophe and not post-Flood processes. Pediments and the long-distance spread of well-rounded quartzites also points to the Flood. Furthermore, there are many climatic problems if the GRF and associated formations were post-Flood. Based on multiple criteria, it is believed that the Flood/post-Flood boundary is in the ‘late Cenozoic’ over the western [sic – USA?].

Whitmore J.H., ‘Difficulties with a Flood model for the Green River Formation’, Journal of Creation 2006;20(1):81-85.

Abstract. Some problems, though not insurmountable, exist with a lake model for the origin of the Green River Formation (GRF). However, critical evaluation of Oard’s Flood model shows it simply is not supported by field observations. His Flood model raises far more questions than it answers. Instead, the data clearly indicate the GRF was deposited within lakes, after the Flood.

New model for catastrophic slide

2006-03-08T09:53:00.000-08:00

A paper in the latest issue of Geology presents a new model for the emplacement of the Heart Mountain detachment, one of the most spectacular and puzzling gravity slide features on the surface of the Earth. Part of its mystery is its massive size (over 3400 km2) and the low-angle surface (~2°) on which it moved. Aharonov and Anders (2006) suggest that the extensive dyke network associated with the Eocene Absaroka Volcanics heated trapped waters near its base, resulting in overpressuring sufficient to initiate the catastrophic sliding that traversed more than 45 km.

Aharonov E., Anders M.H., ‘Hot water: a solution to the Heart Mountain detachment problem?’, Geology 2006;34(3):165-168.

Abstract. The Heart Mountain block slide of northwestern Wyoming and southwestern Montana is one of the largest slides known to have occurred in Earth’s history. This early Eocene block slide covered an area of over 3400 km2 and moved a minimum of 45 km across open terrain. The initial 2- to 4-km-thick Heart Mountain block slide moved on a slope of about 2°, detaching for half its length on a nondescript bedding plane in the Ordovician Big Horn Dolomite (BHD). Given our current understanding of fundamental mechanics, such a great mass of rock should not have begun sliding on such a gentle slope without some special condition. Here we suggest that a special condition existed during the interval between extensive upper-plate dike injections and the initial movement phase. In our model, the dike injections increased horizontal stresses and heated the surrounding layers. Both the increased stresses and the heat input elevated fluid pressure of water trapped within the BHD. In addition, vertical hydrofracturing was retarded as horizontal stress approached vertical, thus allowing a critical buildup of fluid pressure. Fluid overpressuring is a mechanism that can overcome the mechanical problem of initiating movement on a low-angle surface. Moreover, this mechanism explains the observed fluidized features found along the basal contact of the slide block as well as the observed lack of deformation in the lower plate.

Re-evaluation of 'Spirorbis'

2006-02-23T13:51:00.000-08:00

A paper in the March 2006 edition of the Journal of the Geological Society reinterprets pre-Cretaceous 'Spirorbis' worm tubes as those of microconchids. Whereas modern Spirorbis is a stenohaline polychaete annelid, microconchids are possibly lophophorates and are known from freshwater, brackish and hypersaline environments. This has palaeoenvironmental implications, as well as impacting upon a creationist argument for the marine deposition of coal - as the authors point out: "Creationist literature (e.g. Coffin 1975) has argued for the rapid formation of coal in the sea during the Biblical Flood on the basis of finding marine 'Spirorbis' attached to trees and other terrestrial plants in Carboniferous Coal Measures. This argument becomes untenable with the knowledge that the tube-worms concerned were not stenohaline spirorbid polychaetes." (p.227)

Taylor P.D., Vinn O., 'Convergent morphology in small spiral worm tubes ('Spirorbis') and its palaeoenvironmental implications', Journal of the Geological Society 2006;163:225-228.

Abstract: Calcareous tube-worms generally identified as Spirorbis range from Ordovician to Recent, often profusely encrusting shells and other substrates. Whereas Recent Spirorbis is a polychaete annelid, details of tube structure in pre-Cretaceous 'Spirorbis' suggest affinities with the Microconchida, an extinct order of possible lophophorates. Although characteristically Palaeozoic, microconchid tube-worms survived the Permian mass extinction before being replaced in late Mesozoic ecosystems by true Spirorbis. Recent Spirorbis is stenohaline but spirorbiform microconchids also colonized freshwater, brackish and hypersaline environments during the Devonian-Triassic. Anomalies in the palaeoenvironmental distributions of fossil 'Spirorbis' are explained with the recognition of this striking convergence between microconchids and true Spirorbis.

Thoughts on the pre-Flood/Flood boundary

2006-02-21T08:32:00.000-08:00

In a paper in the latest edition of Origins, published by the Geoscience Research Institute, Kurt Wise and Andrew Snelling interpret a stromatolite-rich horizon in Proterozoic sediments of Grand Canyon as the partial remains of an extensive hydrothermal biome that existed around the margins of the North American continent in pre-Flood times. Here is the abstract of their paper – but follow the link for the full-text version.

Wise KP, Snelling AA, ‘A note on the pre-Flood/Flood boundary in the Grand Canyon’, Origins (Geoscience Research Institute) 2005;(58):7-29.
http://www.grisda.org/origins/58007.pdf

Abstract: The most extensive stromatolite horizon known in Grand Canyon sediments is found in the base of the Awatubi Member of the Kwagunt Formation of the Chuar Group. It is suggested that the greater functionality of growing, compared with fossil, stromatolites indicates that they were formed by secondary process and not directly created by God. The top-heavy upright orientation of the stromatolites in the Awatubi bed suggests they were formed in situ, which in turn suggests that they predate the Genesis Flood and postdate the Day Three Regression, contra earlier suggestions by the authors (Snelling 1991, Wise 1992). On the other hand, it is consistent with Austin and Wise’s (1994) suggestion that the base of the Sixtymile Formation (overlying the Kwagunt Formation) represents the pre-Flood/Flood boundary in Grand Canyon and Austin’s (1994) suggestion that the Chuar Group was formed in antediluvian times. Good preservation of organics and no preservation of higher organisms suggests that Wise’s (2003) hydrothermal fringing reef model for sediments near Death Valley also applies to Grand Canyon’s correlative Chuar Group sediments and contained Awatubi stromatolites. The Awatubi stromatolites thus formed an intertidal “forest” about hot springs in an intertidal region at the edge of the pre-Flood continent, hundreds of kilometers from land.

The accompanying photograph shows stromatolitic laminations in Proterozoic sediments of Grand Canyon.

The mysterious case of the missing loess

2006-02-20T02:25:00.000-08:00

An intriguing paper concerning periglacial loess (aeolian silt) has been published in the February 2006 issue of Earth-Science Reviews. One of the problems discussed in this review is that much less loess is deposited nowadays in periglacial areas than during the last ice age (apart from, possibly, Alaska). Although we might expect a belt of loess to be deposited in front of the present-day ice caps, hardly any significant recent loess is to be found. The standard uniformitarian principle (“the present is the key to the past”) appears not to apply to loess formation. A second problem raised by the review is the almost complete lack of loess deposits from ice ages before the last one (although there are claims of some pre-Pleistocene loessites, not necessarily deposited under periglacial conditions). Removal by erosion during interglacial episodes is said to be inadequate to explain their almost universal absence. Further evidence, perhaps, that there was only one ice age in recent Earth history, consistent with the young-age creation model?

van Loon AJ, ‘Lost loesses’, Earth-Science Reviews 2006;74(3-4):309-316.

Abstract: Loesses form wide belts in front of previously glaciated areas. Their thicknesses may be considerable, changing in Eurasia from maximally a few metres in the west to a hundred metres or more in the east. The Eastern (particularly Chinese) loesses are mostly unrelated to glaciations. The periglacial loesses from China and elsewhere predominantly date from the last Pleistocene glaciation: relatively few comparable occurrences are known from earlier Quaternary glaciations. As it is difficult to imagine that the conditions in front of the land-ice masses during the earlier glaciations differed fundamentally from those of the last one, considerable quantities of loess must have disappeared. This disappearance, which is commonly ascribed to fluvial and eolian erosion, is not easily explained as equivalent deposits that may have the older loesses as a source, are practically absent. A possible explanation might be that loess is recycled during successive glaciations. Some loess disappears during interglacials by erosion, but this quantity is more than compensated by the formation of new silt particles. The implication would be that the loess deposits increase in volume for each new glaciation.

Large-scale trends in Phanerozoic palaeocurrents

2006-02-17T10:57:00.000-08:00

Palaeocurrent data provide fascinating insights into sediment dispersal patterns in the geological past – and some remarkable trends are being revealed by ongoing analysis of a huge database of measurements from across the North American continent. Arthur Chadwick of Southwestern Adventist University has compiled data from over half a million measured palaeocurrent vectors at fifteen thousand locations from the Phanerozoic of North America. His work verifies the stable southwesterly pattern of palaeocurrents across the continent documented by earlier workers and demonstrates its persistence with some variation throughout the Palaeozoic. In the Mesozoic the currents show increasing variability and shift from predominantly westerly to predominantly easterly. By the middle of the Cenozoic there is no discernible continent-wide palaeocurrent pattern, and sedimentation seems to be more basinal. These patterns reflect major changes in global current trends – and any successful model of Earth history needs to be able to account for them.

For more information see:
‘Megatrends in North American paleocurrents’
http://origins.swau.edu/papers/global/paleocurrents/default.html

‘Lithologic, paleogeographic, and paleocurrent maps of the world’
http://geology.swau.edu/paleocurrents_1.html

Petrification of wood takes only “tens to hundreds of years”

2006-02-17T09:27:00.000-08:00

Experimental work by Japanese scientists has confirmed that the petrification of wood can take place rapidly under the right chemical conditions (Akahane et al 2004). Pieces of alder wood placed in an overflow stream from Tateyama Hot Spring in central Japan were almost 40% silicified in seven years. Most petrified wood in the fossil record is associated with volcanic sediments, suggesting that it was formed when hot mineral-laden waters permeated the wood. Indeed, samples of Miocene fossil wood show the same type of mineralization as the experimentally petrified wood, revealing that a similar process was involved in their formation. Significantly, and somewhat unusually, the Japanese study favourably cited an earlier article on the rapid petrification of wood which was published in a creationist journal (Snelling 1995; Snelling 2005).

Akahane H, Furuno T, Miyajima H, Yoshikawa T, Yamamoto S, ‘Rapid wood silicification in hot spring water: an explanation of silicification of wood during the Earth’s history’, Sedimentary Geology 2004;169(3-4):219-228.

Abstract: A hot spring water lake in Tateyama Hot Spring has a high content of silica and readily precipitates silica spheres and deposits of opal. Abundant fragments of naturally fallen wood impregnated with silica were found in the overflow stream of the lake. These silicifications resulted from the precipitation of silica spheres onto split surfaces or cell walls of the fallen wood. The textures of wood tissues are the same as those found on naturally silicified wood formed in the vicinity of volcanic regions in the geological record. These results explain the formation mechanism of certain naturally silicified wood fragments that seem to be formed under the same conditions as those found in the hot spring water. To confirm the silicification process, fresh wood pieces of alder wood (Alnus pendula Matsumura) were placed in the hot spring water stream. Experimental wood fragments were silicified to nearly 40% by weight over a period of 7 years by the deposition of amorphous silica spheres in cell lumina of wood tissue. This study reveals that silicified wood can form under suitable conditions in time periods as short as tens to hundreds of years, and contributes to the understanding of the mechanisms forming silicified wood.

Snelling AA, ‘“Instant” petrified wood’, Creation 1995;17(4):38-40.
http://www.answersingenesis.org/creation/v17/i4/wood.asp

Snelling AA, ‘Rapid petrification of wood: an unexpected confirmation of creationist research, Institute for Creation Research Impact Article #379, January 2005.
http://www.icr.org/index.php?module=articles&action=view&ID=13

Extraordinary fossil whale preservation

2006-02-17T04:17:00.000-08:00

A team of creationist researchers led by Leonard Brand of the Department of Natural Sciences, Loma Linda University, has documented dramatic evidence of rapid diatomite accumulation in the Pisco Formation of Peru. The unusual preservation of numerous baleen whales in the diatomaceous sediments seems to require astonishingly rapid rates of deposition, unlike those observed in the present day. The investigators concluded that the most viable explanation was burial fast enough to cover whales 5-13 m long and about 50 cm thick within a few weeks or months. Their paper made the cover of the February 2004 issue of Geology, a premier publication of the Geological Society of America.

Brand LR, Esperante R, Chadwick AV, Porras OP, Alomia M, ‘Fossil whale preservation implies high diatom accumulation rate in the Miocene-Pliocene Pisco Formation of Peru’, Geology 2004;32(2):165-168.

Abstract: Diatomaceous deposits in the Miocene-Pliocene Pisco Formation contain abundant whales preserved in pristine condition (bones articulated or at least closely associated), in some cases including preserved baleen. The well-preserved whales indicate rapid burial. The 346 whales within 1.5 km2 of surveyed surface were not buried as an event, but were distributed uninterrupted through an 80-m-thick sedimentary section. The diatomaceous sediment lacks repeating primary laminations, but instead is mostly massive, with irregular laminations and speckles. There is no evidence for bioturbation by invertebrates in the whale-bearing sediment. Current depositional models do not account for the volume of diatomaceous sediments or the taphonomic features of the whales. These taphonomic and sedimentary features suggest that rapid burial due to high diatom accumulation, in part by lateral advection into protected, shallow embayments, is responsible for the superb preservation of these whales, leading to a higher upper limit on phytoplankton accumulation rates than previously documented.

Fossil reefs: some selected resources

2006-02-17T03:14:00.000-08:00

Buried structures resembling reefs are found throughout the geological record. Obviously, if these structures grew slowly in the places where we now find them, it would suggest that the sedimentary layers containing them took a long time to form. However, the identification of these structures is often questionable. Most fossil “reefs” are different from present-day reefs, with a different configuration, different kinds of organisms involved in their formation and a notable absence of the rigid biological framework necessary for producing a real wave-resistant reef structure (Hodges 1987; Roth 1995). Some of these structures may not be true reefs at all. Others may be reefs that grew somewhere else and have been transported to where we now find them. Young-age creationists have published reinterpretations of classic “reef” structures – including the Gotland reefs (Scheven 1990), the Thornton Quarry complex (D’Armond 1980) and the Capitan reef (Nevins 1972; Nevins 1974).

The accompanying photograph shows part of the Capitan Reef Complex (Permian) of Guadalupe Mountains National Park, Texas.

References:

D’Armond DB, ‘Thornton Quarry deposits: a fossil coral reef or a catastrophic flood deposit? A preliminary study’, Creation Research Society Quarterly 1980;17(2):88-105.

Hodges LT, ‘Fossil binding in modern and ancient reefs’, Origins (Geoscience Research Institute) 1987;14(2):84-91. www.grisda.org/origins/14084.htm

Nevins SE, ‘Is the Capitan Limestone a fossil reef?’, Creation Research Society Quarterly 1972;8(4):231-248.

Nevins SE, ’Reply to critique by Daniel Wonderly’, Creation Research Society Quarterly 1974;10(4):241-244.

Roth AA, ‘Fossil reefs and time’, Origins (Geoscience Research Institute) 1995; 22(2):86-104. www.grisda.org/origins/22086.htm

Scheven J, ‘The Flood/post-Flood boundary in the fossil record’, pp.247-266 in: Walsh RE, Brooks CL (editors), Proceedings of the Second International Conference on Creationism, Creation Science Fellowship: Pittsburgh, Pennsylvania, 1990.

Was the Coconino Sandstone deposited underwater?

2006-02-16T12:42:00.000-08:00

The Coconino Sandstone (Permian) of Grand Canyon, Arizona, is conventionally thought to have been deposited in a desert environment. However, studies of fossil trackways preserved in the Coconino have caused some geologists to question the traditional aeolian interpretation. A new study of sand-filled cracks penetrating the Hermit Shale at the base of the Coconino also suggests that alternative depositional models should be considered. These cracks have usually been thought to be ‘mudcracks’ caused by desiccation in a terrestrial environment, but there are several features of the cracks that render this interpretation suspect. For more information, here’s the abstract of the new study. A full-text PDF of the article can be downloaded by Creation Research Society members.

Whitmore JH, ‘Origin and significance of sand-filled cracks and other features near the base of the Coconino Sandstone, Grand Canyon, Arizona, USA’, Creation Research Society Quarterly 2005;42(3):163-180.
http://www.creationresearch.org/crsq/abstracts/Abstracts42-3.htm

Abstract: Conventional geology proposes that the Coconino Sandstone formed when wind-blown desert sand migrated over the mud-cracked floodplains of the Hermit Formation. The contact between these two Permian formations was studied along ten trails in the Grand Canyon. Special attention was given to sand-filled cracks that occur at the base of the Coconino penetrating the Hermit, features usually interpreted as mud cracks. The most notable cracks are widest (up to 25 cm) and deepest (up to 10 m) along the Bright Angel Fault on the South Rim. Cracks are always present near major faults, but become narrower, shallower and are sometimes absent altogether as horizontal distance from faults increases and vertical displacement along faults decreases. Vertical laminations within the cracks, U-shaped cracks, cracks that dissipate upwards, slickensides not caused by faulting and other features make the mud crack theory suspect. They might be better explained as clastic dikes (or sand intrusions) which originated by injection during tectonic activity after the deposition of the Coconino Sandstone. Evidence near the base of the Coconino such as load casts, burrows and vertebrate trackways, suggests the Coconino was rapidly deposited in an aqueous environment. Cross-cutting relationships indicate the Bright Angel Fault was active during the Precambrian, then quiescent until the Cenozoic (Miocene to Pliocene). If the clastic dikes were caused by tectonic activity, either the Coconino was unlithified or only partially lithified in excess of 200 million years (unlikely, in a conventional scenario) or that only a short amount of time passed between deposition and faulting, greatly reducing the supposed duration of geologic time.

The accompanying photograph shows the abrupt contact between the Coconino Sandstone (above) and the Hermit Shale (below) exposed along the Bright Angel Trail in Grand Canyon, Arizona.

New monograph on ice cores

2006-02-16T12:23:00.000-08:00

A major objection to the young-age timescale has been the apparent discovery by glaciologists of hundreds of thousands of annual layers in cores taken through the Antarctic and Greenland ice sheets. However, a new technical monograph by meteorologist Michael Oard explores the origin and development of the ice sheets and concludes that long timescales are automatically built into the conventional interpretation of the ice core data. Furthermore, he makes a case for only one ‘ice age’ rather than a succession of Pleistocene ‘ice ages’, and outlines some of the problems with annual layer counting and standard glaciological flow models. This monograph is required reading for anyone seriously interested in exploring the ice core data. Unfortunately I’m not aware of a UK supplier of this 210-page monograph, but it can be ordered from the website of the Institute for Creation Research:

Oard MJ, The Frozen Record: Examining the Ice Core History of the Greenland and Antarctic Ice Sheets, Institute for Creation Research, El Cajon, CA; 2005. ISBN 0-932766-82-X.
http://www.icr.org/store/index.php?main_page=pubs_product_book_info&products_id=2608

Helium diffusion studies survive criticism

2006-02-15T14:49:00.000-08:00

One of the projects undertaken by the RATE (Radioisotopes and the Age of The Earth) team was a study of the high helium retention of ancient crustal rocks:

Humphreys DR, Austin SA, Baumgardner JR, Snelling AA, ‘Helium diffusion rates support accelerated nuclear decay’, pp.175-195 in: Ivey R.L. (editor), Proceedings of the Fifth International Conference on Creationism, Creation Science Fellowship, Pittsburgh, PA; 2003.

Humphreys DR, Austin SA, Baumgardner JR, Snelling AA, ‘Helium diffusion age of 6,000 years supports accelerated nuclear decay’, Creation Research Society Quarterly 2004;41(1):1-16.
http://www.creationresearch.org/crsq/articles/41/41_1/Helium.htm

Two decades ago, there were reports of surprisingly high amounts of nuclear-decay-generated helium in tiny radioactive zircon crystals (embedded in mica) from the Jemez Granodiorite (Precambrian) of New Mexico. Up to 58% of the helium expected from 1.5 billion years of decay was still in the zircons. Why hadn’t the helium diffused out of the zircons and into the atmosphere? Astonishingly, borehole temperatures and measurements of diffusion coefficients indicate that the zircons could have retained the observed levels of helium only if the time scale of diffusion was about 6,000 years. This suggests that a large amount of helium has been generated by nuclear decay but that it was generated so recently that it has not had time to escape from the zircons by diffusion. This is consistent with accelerated nuclear decay in the Earth’s recent past.

A lengthy – and somewhat ‘waffly’ – critique of this work by Kevin Henke appeared on 17 March 2005 on the anti-creationist Talk Origins website:

Henke KR, ‘Young-earth creationist helium diffusion “dates”: archived original version’
http://www.talkorigins.org/faqs/helium/original.html

This soon led to an ongoing web debate between Henke and RATE investigator Russ Humphreys who replied to Henke’s first critique on 27 April 2005:

Humphreys DR, ‘Helium evidence for a young world remains crystal-clear’
http://www.trueorigin.org/helium01.asp

On 24 November 2005, Henke responded by revising and updating his original article:

Henke KR, ‘Young-earth creationist helium diffusion “dates”: fallacies based on bad assumptions and questionable data
http://www.talkorigins.org/faqs/helium/zircons.html

Then, on 6 January 2006, Humphreys replied to Henke’s second attempt to refute the helium data:

Humphreys DR, ‘Helium evidence for a young world overcomes pressure’
http://www.trueorigin.org/helium02.asp

It has been fascinating to see this exchange develop – but it seems to me that Humphreys’ original conclusion, which is that the helium diffusion data point to young age, is still pretty robust. So far, Henke has failed to find a “show-stopping” flaw in the argument. But why not read the articles and see for yourself?

Flood Activated Sedimentation and Tectonics (FAST)

2006-02-15T08:39:00.000-08:00

Following on the success of its RATE (Radioisotopes and the Age of The Earth) research, the Institute for Creation Research has announced its intention to undertake similar initiatives in other fields:

Vardiman L, ‘What comes after RATE?’, Institute for Creation Research Impact Article #387, September 2005.
http://www.icr.org/index.php?module=articles&action=view&ID=2468

One of the proposed initiatives is FAST (Flood Activated Sedimentation and Tectonics), a grouping of several geological subprojects in which Dr Steve Austin and others will be investigating catastrophic processes in Earth history that could seriously challenge conventional geological interpretations. Furthermore, RATE II will continue research on selected subprojects from RATE which need additional documentation. For example, RATE studied only terrestrial rocks, but RATE II will include meteorite data. Also, there is a need to expand the data set collected by RATE on helium diffusion, isochron discordance, carbon-14 in diamonds, radiohalos, fission tracks and potassium-40 in fossil insects.

The accompanying photograph shows one of billions of nautiloids within the Whitmore Wash Member of the Redwall Limestone of Grand Canyon. This extensive mass-kill horizon was discovered by Dr Austin and investigation of the dynamics of the burial process may be one of the new FAST research projects.

New perspectives on granite plutonism

2006-02-15T08:00:00.000-08:00

The last decade or so has seen a revolution in thinking about the origin and emplacement of large granite plutons. What was once thought of as slow and continuous is now regarded as rapid and episodic. Those interested in pursuing this topic may want to read this contribution by J. D. Clemens in the Proceedings of the Geologists' Association:

Clemens JD, 'Granites and granitic magmas: strange phenomena and new perspectives on some old problems', Proceedings of the Geologists' Association 2005;116:9-16.

Abstract: Granitic plutons generally afford pleasant, mostly unchallenging landscapes. However, on closer inspection of some of the outcrops, one may discover some strange, beautiful and baffling examples of patterns produced by geochemical and mineralogical self-organization. Fascinating as they are, these features probably reveal little about the origins of granitic magmas. It is the more usual features that one needs to study and understand, using geophysics, geochemistry, isotope petrology, textural analysis and various kinds of theoretical modelling. Many granites are products of high-temperature melting of continental crust and there is a relationship between upper granulite-facies metamorphism and the generation of granitic magmas. The heat needed for this process commonly comes from mafic magmas intruded into the deep crust and the melting reactions take place in the absence of free fluids. The relatively low viscosity and density of hydrous granitic magmas control the ascent and emplacement processes and the viscosity is not greatly changed during crystallization and cooling, at least for the first few tens of percent crystals. Modelling shows that granite diapirism is slow and inefficient and there is little evidence of it in the geological record. The granitic melt segregates into veins, shears and dykes, eventually forming larger feeder dykes that transport the magma rapidly upward to the emplacement sites. The potential speed of ascent and emplacement mean that even very large granitic plutons probably grow in thousands of years. Experimental data on crystallization rates suggest that many of the large crystals observed in granitic rocks could have grown in a matter of hours – certainly in no more than a few tens of years. Geological processes are commonly thought of as slow and continuous, but many are rapid and episodic. Granitic plutonism is of the latter kind.

The accompanying photograph shows a sample of porphyritic granite from the Shap Pink Quarry, Shap Fell in the English Lake District.

Confirmation of rapid metamorphism of rocks

2006-02-15T06:02:00.000-08:00

Eclogite-grade metamorphism is conventionally thought to involve high temperatures and very high pressures. The usual scenario for eclogite formation is considered to be below 60 km, at the base of a subduction zone, and at a temperature of around 700 °C. However, new work on Norwegian eclogites suggests that spasmodic surges of hot fluids, each lasting ten years or less, and at lower-than-expected temperatures (<400°C) caused eclogitization of the precursor granulites (Comacho et al 2005). These shorter timescales "will make many geologists draw breath" (Kelley 2005).

Furthermore, independent confirmation of these rapid fluid flows has been reported by Snelling (2005; 2006). A sample of related eclogite containing biotite flakes was closely examined and polonium-210 radiohalos were found in it (7 polonium-210 radiohalos in 50 microscope slides, each containing 20-30 biotite flakes). This discovery, the first time any radiohalos have been documented in eclogites, is highly significant. Biotite was not in the precursor granulites, so it had to form as a result of both their metamorphism to eclogite and the fluid flows. Furthermore, because there was no source of either parent uranium-238 or its radioactive decay products within either the eclogites or the precursor granulites, the large quantities of polonium-210 required to generate these radiohalos had to have been transported from external sources into the biotite flakes within these rocks by the hot fluids. But the polonium-210 only has a half-life of 138 days, and the radiohalos would only have formed and survived after the temperature in the rocks fell below 150 °C. So this drastically restricts the duration of the fluid flows and associated eclogite metamorphism even more, perhaps to only a few weeks or months.

References:

Camacho A, Lee JKW, Hensen BJ, Braun J, 'Short-lived orogenic cycles and the eclogitization of cold crust by spasmodic hot fluids', Nature 2005;435:1191-1196. http://www.nature.com/nature/journal/v435/n7046/abs/nature03643.html

Kelley S, 'Geophysics: Hot fluids and cold crusts', Nature 2005;435:1171.

Snelling AA, 'Radiohalos in granites: evidence for accelerated nuclear decay', pp.101-207 (especially Table 4, p.188) in: Vardiman L, Snelling AA, Chaffin EF (editors), Radioisotopes and the Age of the Earth: Results of a Young-Earth Creationist Research Initiative, Institute for Creation Research, El Cajon, CA, and Creation Research Society, Chino Valley, AZ; 2005.

Snelling AA, 'Confirmation of rapid metamorphism of rocks', Institute for Creation Research Impact Article #392, February 2006.http://www.icr.org/index.php?module=articles&action=view&ID=2603