Fractal Plate Reconstruction Table 2

Age (Ma)		2.581	6.033	11.040	19.722	26.154	28.715	31.116	33.738	37.771
Latitude		12.395	11.906	11.049	12.850	13.126	13.039	13.032	13.303	14.622
Longitude		41.738	40.366	37.655	32.877	34.052	34.616	34.722	34.352	32.585
Angle		1.001	4.057	6.781	12.168	15.947	17.272	18.670	20.360	22.499
SAF	I	0.4982	0.5018	0.5242	0.5100	0.4970	0.4840	0.4851	0.4983	0.4887
	II	0.4664	0.4408	0.5585	0.5320	0.5254	0.5416	0.5398	0.5177	0.5025
	III	0.4652	0.5000	0.5601	0.5414	0.5302	0.5109	0.5007	0.4965	0.4749
	IV	0.5002	0.5078	0.5083	0.5279	0.5468	0.5502	0.5437	0.5303	0.5000
	V	0.5000	0.5242	0.5000	0.5038	0.5000	0.5000	0.5000	0.5000	0.5000
	VI	0.4890	0.4751	0.4907	0.5039	0.5336	0.5030	0.4863	0.4904	0.5000
	VII	0.5000	0.4730	0.5000	0.5000	0.5000	0.5000	0.5519	0.5000	0.4654
	VIII	0.5000	0.5000	0.5000	0.5000	0.5000	0.5515	0.5343	0.5186	0.5000
	IX	0.5000	0.5000	0.5000	0.5000	0.5000	0.5000	0.5109	0.5576	0.5285
	X	0.5311	0.5343	0.4991	0.5248	0.5449	0.5526	0.5495	0.5370	0.5000
	FZs	0.5000	0.5000	0.5000	0.5000	0.5000	0.5000	0.5000	0.5000	0.5000

Table 2. Final segment rotation parameters and asymmetry factors for magnetic isochron crossing ages, Australian and Antarctic oceanic plates. Partial rotation angle for Antarctic plate to the ridge is the asymmetry factor multiplied by the total rotation angle. For the Australian plate the partial rotation angle to the ridge is (1.0 – the asymmetry factor) multiplied by the total rotation angle. In the absence of data points, asymmetry factor is assumed to be 0.500. 

© 2010 Rex H. Pilger, Jr.
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Fractal Plate Reconstruction Table 1

Age (Ma)	Initial			Final
	Longitude	Latitude	Angle	Longitude	Latitude	Angle
0.000*	41.800	11.300	0.633	--	--	--
2.581	40.300	11.164	1.655	41.738	12.395	1.001
5.000	40.638	11.446	3.192	40.972	12.123	3.151
6.033	40.770	11.591	3.830	40.366	11.906	4.057
10.000	38.728	11.830	6.184	37.759	11.025	6.314
11.040	37.942	11.896	6.790	37.655	11.049	6.781
15.000	35.773	12.481	9.140	37.796	12.082	8.980
19.722	34.370	13.393	12.051	32.877	12.850	12.168
20.000	34.304	13.437	12.225	32.695	12.874	12.356
25.000	33.520	13.840	15.275	33.610	13.141	15.345
26.154	33.556	13.805	15.919	34.052	13.126	15.947
28.715	33.984	13.580	17.319	34.616	13.039	17.272
30.000	34.234	13.466	18.148	34.718	13.015	17.989
31.116	34.377	13.396	18.890	34.722	13.032	18.670
33.738	34.377	13.451	20.495	34.352	13.303	20.360
35.000	34.326	13.666	21.324	33.934	13.599	21.122
37.771	33.475	14.650	22.882	32.585	14.622	22.499
39.464	32.000	15.600	23.300	31.845	15.459	23.506
40.000	31.465	15.924	23.398	33.419	16.267	26.186

Table 1. Initial and final total finite rotation parameters, degrees, Antarctic and Australian plates. Initial parameters are converted to normalized pseudovectors assigned magnitudes equal to total rotation rate for each age and then interpolated in each of the three dimensions via cubic splines at 5 m.y. intervals.
Sources: Cande and Stock (2004, in italics), Müller et al. (2008; 39.424 Ma). Timescale: Gradstein et al. (2004)

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Fractal Plate Reconstruction?

Fractal Plate Reconstructions, Seafloor Spreading Asymmetry, and Kinematics utilizing Fractal Criteria

Summary

Information theory and fractal analysis provide a basis for a new approach to plate reconstructions of magnetic isochrons and fracture zone crossings. The new approach models accretionary boundaries as fractals (via variable binning sizes) and seeks parameter sets that produce a minimum sum of logarithms of bin numbers. Spline interpolation of a trial reconstruction parameter set, including spreading asymmetry along ridge segments, and Monte Carlo modifications to the parameters provide iterative calculation of the full fractal set. Such a method allows for incorporation of all isochron identifications from the plates of interest in a single, iterative calculation set rather than just a few separate, selected individual reconstruction calculations. The splined parameter sets also provide a means for calculating instantaneous rotation rates and asymmetries. More detailed analysis of the fractal results for a number of the “best” solutions also provides alternative approaches to characterization of the uncertainty in the derived reconstruction parameters; more work will be required in this area.

Paleostress maps - updated

The Western United States paleostress maps in a previous post are largely based on a compilation used in Pilger (2003).

The merged data set, including Bird's (2002) data set, mentioned in the immediately previous post, has been used for updating the earlier maps. The s_H1 measurements are in light blue for the first 5 m.y. of each 10 m.y. interval and dark blue for the last 5 m.y. Tangents to calculated instantaneous kinematic small circles (see Pilger, 2003, for a description of methodology) are calculated each 5 m.y. as labeled. (Click graphic to enlarge. Click Back button or icon to return to post.)

0-10 Ma

Merged Paleostress Data Sets

Paleostress data from Peter Bird's (2001) and Rex Pilger's (2003) compilations have been merged: link. References are also included.

It is my intention to continue adding to this data set and maintain its public availability. Please send comments and additional contributions/corrections to rexpilger (at) gmail (period) com.

Paleostress data - asking for more

Most of the paleostress data presented in maps by Pilger (2003) and in earlier webposts (here and here) are available at this link.

The World Stress Map project largely consists of contemporary or at most Recent data, and not paleostress measurements. Peter Bird has compiled a separate, partially overlapping data set with different constraints. Yet, together, the compilations are woefully inadequate, especially outside the US Cordillera. In light of the growing importance of fracture reservoirs for petroleum and gas, knowledge of paleostresses and paleofractures is valuable for exploration and development of such resources.

If you have additional paleostress data, I would welcome the opportunity to add them to the data store. Please email rexpilger (at) gmail (dot) com.

AAPG: Intracontinental Tectonics, Stresses, and Fracture Reservoirs

From Spring, 2010, AAPG Meeting in New Orleans:
http://www.searchanddiscovery.com/documents/2010/40653pilger/ndx_pilger.pdf

Intracontinental Tectonics, Stresses, and Fracture Reservoirs - Clues from Plate Kinematics

Introduction

Now in its sixth decade, plate tectonics has reshaped the understanding of the evolution of the Earth, especially the origin of major earthquakes, ocean basins, mountain belts, and magmatism. Elaboration of the theory relative to hydrocarbon exploration and development has provided insight into the nature of continental margin sedimentary basins, especially in concert with improved understanding of stratigraphic sequencing, fluid pressures and migration, diagenesis, and compaction. Plate tectonics has also provided a framework for understanding compressional thrust belts associated with convergent plate boundaries, both continental to continental and continental to oceanic plate.

Plate Frames in Wordle

Plate Frames in Wordle:

Alien Science

Bloggers are afire with the "news" of a United Nations designated representative for future encounters of humanity with intelligent alien life. So the Sunday Times tell us via the Aussies (link via First Things). Try a Bing search for a hint of the excitement. Alas, Trekkies, it's apparently not so. No, the all-knowing UN hasn't overreached this far, yet.
I recall an episode of Johnny Carson's Tonight Show, years ago, in which the clever host asked his audience the rhetorical question (paraphrased from aging memory): "Why do the UFO's always land in places like Roswell? Why not Central Park?"
I'm a geologist/geophysicist by training and profession. Is the public aware, and have my fellow geoscientists realized, that in the earth's four billion year rock record there have been found no, none, nada, zip, zero... traces of evidence of any extraterrestrial intelligence: fossilized tricorders, abandoned transporter chambers or obsolete stargate molds, detached Enterprise engine imprints?

Organized Science and Its Dirty Little Secret

If there is a recognized deity in the world of organized science, one of its names is “Peer Review”. Before results of any serious scientific investigation are published in a reputable journal, an associate editor farms out the submitted paper to “peers” of the hopeful author(s) (in a few cases the editor may reject a submission without review). Much of the time this process works fairly well; the reviewers provide an evaluation of the would-be contribution: its novelty (has somebody else has produced the same result?), evidence (and further testability), coherence (do the data support the interpretation), and citation of appropriate sources, and makes a recommendation: accept as is (rare), accept with modifications (more common), or go back to the salt mines and here’s why (most common). The editor may solicit numerous reviewers and from the typically one or two returned reviews makes his or her decision on the submission.