The down range geomorphology of MAPCIS (Massive Australian Precambrian/Cambrian Impact Structure) • Background This is the fourth in a series of GSA presentations on MAPCIS. In November of 2007 a 2000km diameter ring was discovered using Google Earth. In 2008 and 2009, the general geomorphology of an oblique impact was described, possible coeval impacts were found and the age was ascertained to be ~545ma. As might be expected from an oblique impact, much of the ejecta and energy are directed down range to form unique and fascinating geomorphology. • Methods Remote imaging and 1: 250,000 GA geology maps defined the surface features. Mining company maps, results from scientific drill cores, magnetic anomaly maps and magnetic intensity maps established a picture of the subsurface, deep structures. These maps were made into overlays to compare and contrast the surface and subsurface geomorphology against models of oblique impacts and other known oblique impact sites. • Results The directly downrange sector is defined by a 62 degree angle opening to the SSW from the impact center to the points where it passes through 100km wide gap between the Petermann Ranges and the Eastern Musgraves. The mountain gap has a signature in both structure (radial ridges/faults) and metamorphic changes. Large pseudotachylite deposits find their furthest distance from the impact within the angle. Significant commercial sulfide deposits of Ni-Cu and PGE’s in the Musgraves are confined to a defined region within the down range angle. Thick non- glacially associated diamictites of early Cambrian age can be found further down range in the Officer Basin. Several circular magnetic anomalies suggest secondary impacts and a SSW ejecta debris flow which continues for over 900km. The lack of a known Acraman Impact 590mya, ejecta layer within the angle completes the picture. • Conclusions The observed geomorphology is consistent with a large oblique impact with a trajectory from NNE to SSW centered at 25°32'55.66"S 131°23'21.50"E dated ~545mya.
At the 2009 GSA NE Meeting in Portland, Maine, a student asked if any minerals associated with impacts were found, (Ni. Cu. or PGEs). I had found none at that time. Research of mining company websites,(BHP Billiton, Rio Tinto, Mithril, Redstone Resources, Pepi Nini and others) found commercial grade strikes of Ni. Cu. Or PGEs., in the following locations.The locations appear to be random and not associated with the impact until……next slide The image at MAPCIS center is the Total Magnetic Intensity Map of the 1:250,000 Ayers Rock geology map. It suggests an excavation from NE to SW before impacting the Musgrave mountains and fanning out.
…..significant impact markers are added. The red angle converges at MAPCIS center and passes through a 100km gap in the Musgrave Range. Yellow(converging radial faults & ridges), Blue(pseudotachylite) Purple(mylonite) Granite and gneiss within the angle are more highly metamorphosed and exhumed from depths of ~45km. Note: 1. The gap is well defined by both geography and rock type. 2. The gap is ~ 60degrees which is consistent with other oblique impacts such as Ries. 3. The bilateral areas of less force on either side of the red angle is consistent with an oblique impact. 4. A downrange overturned flap of lower crust is consistent with models. 5. The Ni, Cu, &PGE enrichment is consistent with an impact and is seen at other sites such as Sudbury 6. The map overlays are 1:250,000 geology maps & Vines 1 is a scientific drill core location.
Mithril fossicking company map shows that claim tenements are widely distributed throughout the Musgrave Province, but commercial grade strikes worth billions are found almost exclusively downrange from MAPCIS. Orange, outlines the main mineral region. Note: Don’t attempt to invest based on these maps, of the companies listed, there are both winners and losers. There is more to making a profit in minerals than just finding them.
In this broader view, we pull back to see further down range. The orange lined mineral zone and pale blue lines of Pt., are our reference points from previous slides. Yellow Neoproterozoic basins form an inner ring. Green, is the Grenville Age, Musgrave Province. Intact Petermann and Musgrave Ranges form blast ejecta shadows, where Minerals are absent and but known sites of 590ma Acraman Impact ejecta survive. Teal, is Cambrian age volcanics. Possible secondary impacts, are located 380 to 650km downrange and are marked by ? marks. Locations of drill holes containing Acraman ejecta are marked with white rings Vines 1 and Empress1/1A do not contain Acraman Ejecta.
Suborbital ejecta Velocities of 10% to 20% of average incoming bolide velocity could travel the distances shown to produce secondary impacts.Simply, it is possible.
Note: 1. The high velocity flow is inline and downrange.2. Empress 1 & Vines 1 drill cores contain diamictite, but no Acraman Ejecta.3. Flows converge at secondary impact sites.4. The area was a shallow sea at the time of impact.5. Massive diamictites were produced in the absence of known glaciations consistent with impact dating.6. The secondary impacts are almost exclusively in the 60 degree downrange angle.7. The secondary impacts cross several distinct geologic domains.6. There is no consensus for explaining either the secondary impact sites or the HVF.
Pg. 75 from “The tectonic history of the Waigen area, western officer Basin, interpreted from geophysical data.” The anomalies/secondary impacts?, cross several domains.
Conclusions: The down range geomorphology is consistent MAPCIS being the result of a huge oblique impact. The economic implications for central Australia are significant. The need for fully funded, academically supported research is the next step. • Coming Spring 2011 • The Gawler Craton: • When did it move? • Where did it move? • Why did it move? • And how is that related to MAPCIS?
References • Johnson David 2004- The Geology of Australia, Cambridge University Press • Glikson, A,Y., and Mernagh, T., 1990, Major pseudotachylite breccia-vein networks, Giles layered basic-ultrabasic complex, western Musgrave Block, central Australia: Jour. Australian Geology and Geophysics, v.11, p. 509-519. • Camacho A., Vernon R.H., Fitzgerald J.D. 1995- Large volumes of Anhydrous pseudotachylite in the Woodroffe Thrust, eastern Musgrave Ranges, Australia, Journal of Structural Geology • Marcus Robert, Melosh H.J., Collins Gareth, 2004 Earth Impact Effects Program: A web based computer program for calculating the regional environmental consequences of a meteoroid impact on Earth, Meteoritics & Planetary Science 40 No. 6, 817-840 (2005) • Hessen Katie Kristine,2008- Oblique Impact Cratering: A comparison of low velocity experiments to high velocity experiments • Reimold Wolf Uwe, Gibson Roger L. 2002- “Pseudotachylites” in large impact structures, • French Bevan M. 1998- Traces of Catastrophe (A Handbook of Shock Metamorphic Effects in Terrestrial Meteorite Impact Structures) Lunar and Planetary Institute • Melosh H.J. 2002- The Mechanics of Pseudotachylite formation in Impact Events, Sweden Impact Conference April 2003. • SEIS-Suspected Earth Impact Sites, Department of Earth and Planetary Sciences,University of Tennessee, Knoxville • Wade B.P, Kelsey D.E., Hand M. and Barovich K.M., 2007- The Musgrave Province: Stitching north, west and south Australia, doi:10.1016/j.precamres.2007.05.007 • Portland, Maine GSA NE Annual meeting(22–24 March 2009) Paper No. 26-4 Presentation Time: 11:40 AM-12:00 PM THE CASE FOR A MASSIVE AUSTRALIAN PRECAMBRIAN CAMBRIAN IMPACT STRUCTURE (MAPCIS). Connelly, Daniel P • Portland, Oregon GSA Annual Meeting (18-21 October 2009) Paper No. 159-4 Presentation Time: 8:35 AM-8:50 AM AGE DATING MAPCIS (MASSIVE AUSTRALIAN PRECAMBRIAN/CAMBRIAN IMPACT STRUCTURE) A MULTI-MODAL INDIRECT APPROACH. Connelly, Daniel P • Portland GSA Annual Meeting (18-21 October 2009) Paper No. 98-4 Presentation Time: 9:00 AM-6:00 PM MAPCIS (MASSIVE AUSTRALIAN PRECAMBRIAN/CAMBRIAN IMPACT STRUCTURE) A POSSIBLE MULTIPLE IMPACT EVENT. Connelly, Daniel P • Andrew C. Hill, Peter W. Haines, Kathleen Grey, and Sebastian Willman-New records of Acraman ejecta in drillholes from the Stuart Shelf and Officer Basin, south Australia, Meteoritics & Planetary Science 42,Nr 11 1883-1891(2007) • C.D. D’Ercole & A.M. Lockwood-The Tectonic history of the Waigen area, western Officer Basin, interpreted from geophysical date. 2003-2004 Annual Review, Geological Survey WA. • H. Zwingmann & DR Nelson- Timing of illite authigenesis in well Empress-1A, Officer Basin, Western Australia. Conference Papers NT Government. • P.W. Haines, R.M. Hocking, K. Grey, M.K. Stevens-Vines 1 revisited: are older Neoproterozoic glacial deposits preserved in Western Australia? April 2008 Australian Journal of Earth Sciences Vol .55 Issue 3 • C.M. Fanning-Prise-Report A96-475 and Report 15- Shrimp U-P zircon geochronology, Petermann Ranges NT
Maps used • Google Earth 2007-2010 • Magnetic Anomaly Map of Australia, 4th Edition 2004 Geosciences Australia • Gravitational Anomaly Map of the Australian Region, 2nd Edition 1997 Commonwealth of Australia • Rock Age Map, Basic geological units of Australia, after Addario et al, created in Arcinfo GIS from public domain geological mapping data, GFDL free use • Cooper, 1st Edition 1970 Sheet SG52-10 Geological Survey of Western Australia • Scott, 1st Edition 1970 Sheet SG52-6 Geological Survey of Western Australia • Mann 1st Edition 1962 Sheet G52-11 Geological Survey of South Australia • Woodruffe 1st Edition 1967 Sheet SG52-12 Geological Survey of South Australia • Petermann Ranges 2nd Ed. 1999 Sheet SG 52-7 Northern Territory Geological Survey • Kulgera 2nd Edition 1992 Sheet SG53-5 Northern Territory Geological Survey • Ayers Rock 2nd Edition 2002 Sheet SG52-8 Northern Territory Geological Survey • Alberga 1st Edition 1959 Sheet G53-9 Geological Survey of South Australia • Ayers Rock, Total Magnetic Intensity Map 2002 Sheet SG52-8 Northern Territory Geological Survey • Company Tenement maps from, Pepi Nini, Redstone Resources, Mithril LTD, BHP Billiton, Goldsearch and others • PIRSA tenement maps for South Australia Timeline from poster Bert Cramer (Alice Springs) writes about the ring in “Sourgrapes & Justice (or 3 comets & a camel)” 1993. deceased 2007. Gene Harvey (Arizona) discovers and reports Google ring, MAM and GAM to scientific community, 2003-2006. Dan Connelly( New Jersey) discovers Google ring, in 2007, and pursues the search for evidence & the wider recognition of MAPCIS to this day.